| University of Bielefeld - Faculty of technology | |
|---|---|
|
Networks and distributed Systems
Research group of Prof. Peter B. Ladkin, Ph.D. |
|
Prepared November 6, 1996
[Preparer's Note: Footnote markers are written in square brackets, e.g., [22], and footnotes appear denoted by the same figures in brackets at the bottom of the same page, separated from the page contents by a dashed line. Typographical errors have been retained in the original as far as possible, except for occasional double full stops at the ends of some paragraphs. PBL]
AERONAUTICA CIVIL
of THE REPUBLIC OF COLOMBIA
SANTAFE DE BOGOTA, D.C. - COLOMBIA
AIRCRAFT ACCIDENT REPORT
CONTROLLED FLIGHT INTO TERRAIN
AMERICAN AIRLINES FLIGHT 965
BOEING 757-223, N651AA
NEAR CALI, COLOMBIA
DECEMBER 20, 1995
Final Report of Aircraft Accident
American Airlines flight 965, December 20, 1995
| 1. | FACTUAL INFORMATION | |
| 1.1 | History of Flight | 1 |
| 1.2 | Injuries to Persons | 5 |
| 1.3 | Damage to Aircraft | 5 |
| 1.4 | Other Damage | |
| 1.5 | Personnel Information | 5 |
| 1.6 | Airplane Information | 9 |
| 1.7 | Meteorological Information | 10 |
| 1.8 | Aids to Navigation | 11 |
| 1.9 | Communications | 11 |
| 1.10 | Aerodrome Information<11> | |
| 1.11 | Flight Recorders | 12 |
| 1.12 | Wreckage and Impact Information | 13 |
| 1.13 | Medical and Pathological Information | 14 |
| 1.14 | Fire | 15 |
| 1.15 | Survival Aspects | 15 |
| 1.16 | Tests and Research | 15 |
| 1.17 | Organizational and Management Information | 21 |
| 1.18 | Additional Information | 22 |
| 2. | ANALYSIS | |
| 2.1 | General | 28 |
| 2.2 | The Decision to Accept Runway 19 | 29 |
| 2.3 | Situational Awareness | 32 |
| 2.4 | Awareness of Terrain | 35 |
| 2.5 | Automation | 40 |
| 2.6 | Crew Resource Management | 46 |
| 2.7 | Speedbrakes | 48 |
| 2.8 | The Cali Approach Controller | 49 |
| 2.9 | FAA Oversight | 51 |
| 2.10 | GPWS Escape Maneuver | 51 |
| 2.11 | Recording of FMS Data | 54 |
| 3 | CONCLUSIONS | |
| 3.1 | Findings | 55 |
| 3.2 | Probable Cause | 57 |
| 3.3 | Contributing Factors | 57 |
| 4 | RECOMMENDATIONS | 58 |
| 5 | APPENDIXES | |
| Appendix | A--Investigation | 62 |
| Appendix | B-- Cockpit Voice Recorder Transcript | 63 |
| Appendix | C--Cali Approach Charts | 64 |
| Appendix | D--American Airlines Ops. Manual page | 65 |
| Appendix | E--Photos of Wreckage | 66 |
| Appendix | F--Route Pages Prior to Impact | 67 |
At 2142 eastern standard time (est) [l], on December 20, 1995, American Airlines Flight 965 (AA965), a Boeing 757-223, N651AA, on a regularly scheduled passenger flight from Miami International Airport (MIA), Florida, U.S.A., to Alfonso Bonilla Aragon International Airport (SKCL), in Cali, Colombia, operating under instrument flight rules (IFR), crashed into mountainous terrain during a descent from cruise altitude in visual meteorological conditions (VMC). The accident site was near the town of Buga, 33 miles northeast of the Cali VOR [2] (CLO). The airplane impacted at about 8,900 feet mean sea level (msl), near the summit of El Deluvio and approximately 10 miles east of Airway W3. Of the 155 passengers, 2 flightcrew members, and 6 cabincrew members on board, 4 passengers survived the accident.
On the previous flight under a different crew, the airplane arrived at MIA from Guayaquil, Equador, at 1438, on December 20, 1996. The Guayaquil to MIA flightcrew reported that there were no significant maintenance or operations-related discrepancies on the airplane. The captain and first officer of AA965 (MIA to SKCL) arrived at the airline's MIA operations office about 1 hour before the proposed departure time of 1640. The operations base manager later stated that
----------------
[1] All times herein are expressed in est, based on the 24-hour clock, unless
otherwise indicated. The Colombian and MIA local time was the same (est).
[2] Very high frequency (VHF) omni-directional radio range.
both the captain and first officer were in his office about 40 minutes before the required check-in time, and appeared to be in good spirits.
According to the AA flight dispatcher at MIA, AA965 was delayed about 34 minutes, waiting for the arrival of connecting passengers and baggage. The flight departed the gate at 1714, and then experienced another ground delay of 1 hour 21 minutes that the flight dispatcher stated was related to gate congestion due to airport traffic. AA965 departed MIA at 1835, with an estimated time enroute to Cali of 3 hour 12 minutes.
AA965 was cleared to climb to flight level (FL) 370 [3]. The route of flight was from MIA through Cuban airspace, then through Jamaican airspace, and into Colombian airspace, where the flight was recleared by Barranquilla Air Traffic Control Center (Barranquilla Center) to proceed from KILER Intersection direct to BUTAL Intersection. The flight then passed abeam Cartegena (CTG). Bogota Center subsequently cleared the flight to fly direct from BUTAL to the Tulua VOR (ULQ)
At 2103, AA965 estimated to Bogota Center that they would cross BUTAL at 2107. As AA965 passed BUTAL, Bogota Center again cleared the flight from its present position to ULQ, and told the flight to report when they were ready to descend. At 2110, AA965 communicated via ACARS [4] with AA's System Operations Control (SOC) center, asking for weather information at Cali. At 2111, Cali weather was reported as clear, visibility greater than 10 kilometers, and scattered clouds. At 2126:16, AA965 requested descent clearance. The flight was initially cleared to FL 240 and then to FL 200. At 2134:04, the flight was instructed to contact Cali Approach Control (Approach).
AA965 contacted Approach at 2134:40. The captain, making the radio transmissions [5] said, "Cali approach, American nine six five." The approach controller replied, "American niner six five, good evening. go ahead." The captain stated, "ah, buenos noches senor, American nine six five leaving two three zero, descending to two zero zero. go ahead sir." The controller asked, "the uh, distance DME [6] from Cali?" The captain replied, "the DME is six three." The controller
----------------
[3] 37,000 feet. Flight levels are expressed in hundreds of feet above msl.
[4]Aircraft Communications Addressing and Reporting System.
[5] Based on the air traffic control (ATC) and cockpit voice recordings (CVR), the captain made the radio communications and the first officer was at the controls of the airplane.
[6]Distance measuring equipment, providing a display in nautical miles.
then stated, "roger, is cleared to Cali VOR, uh, descend and maintain one, fve thousand feet. altimeter three zero zero two.... no delay expect for approach. report uh, Tulua VOR." The captain replied, "OK, understood. cleared direct to Cali VOR. uh, report Tulua and altitude one five, that's fifteen thousand three zero.. zero.. two. is that all correct sir?" The controller stated, "affirmative." The captain replied at 2135:27, "Thank you. At 2135:28, the captain informed the first officer that he had "...put direct Cali for you in there." [7]
At 2136:31, Approach asked AA965, "sir the wind is calm. are you able to [execute the] approach [to] runway one niner?" (see approach charts, appendix C, "VOR DME Rwy 19" and "ILS RWY 01") The captain responded, "uh yes sir, we'll need a lower altitude right away though." The approach controller then stated, "roger. American nine six five is cleared to VOR DME approach runway one niner. Rozo number one, arrival. report Tulua VOR." The captain, replied, "cleared the VOR DME to one nine, Rozo one arrival. will report the VOR, thank you sir." The controller stated, "report uh, Tulua VOR." The captain replied, "report Tulua."
At 2137:29, AA965 asked Approach, "can American airlines uh, nine six five go direct to Rozo and then do the Rozo arrival sir?" The Cali approach controller replied, "affirmative. take the Rozo one and runway one niner, the wind is calm." The captain responded, "alright Rozo, the Rozo one to one nine, thank you, American nine six five." The controller stated, "(thank you very much) [8].... report Tulua and e'eh, twenty one miles ah, five thousand feet." The captain responded, "OK, report Tulua twenty one miles and five thousand feet, American nine uh, six five."
At 2137, after passing ULQ [9], during the descent, the airplane began to turn to the left of the cleared course and flew on an easterly heading for approximately one minute. Then the airplane turned to the right, while still in the descent. At 2139:25, Morse code for the letters "VC" was recorded by navigation radio onto the airplane's CVR. At 2139:29, Morse code similar to the letters "ULQ" was recorded. At 2140:01, the captain asked Approach, "and American uh,
----------------
[7] A reference to the airplane's flight management system (FMS).
[8] "Questionable insertion" transcribed during hearing of the tape by CVR invest1gators.
[9]Position based on ATC and CVR recordings, flight data recorder (FDR) information, time and distance measurements, and reconstructed data from the airplane's flight management computer (FMC). (see section 1.16).
thirty eight miles north of Cali, and you want us to go Tulua and then do the Rozo uh, to uh, the runway, right to runway one nine?" The controller answered, "...you can [unintelligible word] landed, runway one niner, you can use runway one niner. what is (you) altitude and (the) DME from Cali?" The flight responded, "OK, we're thirty seven DME [10] at ten thousand feet." The controller stated at 2140:25, "roger. report (uh) five thousand and uh, final to one one, runway one niner."
The CVR recorded the flightcrew's conversations as well as radio transmissions. At 2140:40, the captain stated, "it's that [expletive] Tulua I'm not getting for some reason. see I can't get. OK now, no. Tulua's [expletive] up." At 2140:49 the captain said, "but I can put it in the box if you want it." The first officer replied, "I don't want Tulua. let's just go to the extended centerline of uh...." The captain stated, "which is Rozo." At 2140:56, the captain stated, "why don't you just go direct to Rozo then, alright?" The first officer replied, "OK, let's...The captain said, "I'm goin' to put that over you." The first officer replied, "...get some altimeters, we'er out of uh, ten now."
At 2141:02, Cali Approach requested the flight's altitude. The flight replied, "nine six five, nine thousand feet." The controller then asked at 2141: 10, "roger, distance now?" The flightcrew did not respond to the controller. At 2141:15, the CVR recorded from the cockpit area microphone the mechanical voice and sounds of the airplane's ground proximity warning system (GPWS), "terrain, terrain, whoop, whoop." The captain stated, "Oh [expletive]," and a sound similar to autopilot disconnect warning began. The captain said, "...pull up baby." The mechanical voice and sound continued, "...pull up, whoop, whoop, pull up." The FDR showed that the flightcrew added full power and raised the nose of the airplane, the spoilers (speedbrakes) that had been extended during the descent were not retracted. The airplane entered into the regime of stick shaker stall warning, nose up attitude was lowered slightly [11], the airplane came out of stick shaker warning, nose up attitude then increased and stick shaker was reentered. The CVR ended at 2141 :28.
The wreckage path and FDR data evidenced that the airplane was on a magnetic heading of 223 degrees, nose up, and wings approximately level, as it struck trees at about 8,900 feet msl on the east side of El Deluvio. The airplane
----------------
[10] 37 DME north of the Cali VOR (CLO) places the airplane 6 miles
south of ULQ and 28 miles north of the approach end of runway 19 at
SKCL.
[11] From FDR data.
continued over a ridge near the summit and impacted and burned on the west side of the mountain, at 3 degrees 50 minutes 45.2 seconds north latitude and 76 degrees 6 minutes 17.1 seconds west longitude. Approach unsuccessfully attempted to contact AA965 several times after the time of impact (see appendix D, two photographs of the accident site).
| Injuries | Flightcrew | Cabincrew | Passengers | Total |
| Fatal | 2 | 6 | 151 | 159 |
| Serious | 0 | 0 | 4 | 4 |
| Minor | 0 | 0 | 0 | 0 |
| None | 0 | 0 | 0 | 0 |
| Total | 2 | 6 | 155 | 163 |
The airplane was destroyed.
None. Impact was in tree-covered mountainous terrain.
The captain and first officer were certified by the U.S. Federal Aviation Administration (FAA) to hold their respective positions in the Boeing 757 (B-757) and each possessed a current first class medical certificate. FAA records showed that neither had been involved in an accident, incident, or enforcement action.
| Pilot In Command | First Officer | |
| Age | 57 | 39 |
| Date of Birth | 11/17/38 | 6/24/56 |
| Date of Hire with American Airlines | 9/22/69 | 10/11/86 |
| First Class Medical Certificate | Issued 12/7/95 |
| Approximate Total Flying Time | 13,000 hrs | 5,800 hrs |
| Total on Type (B757/B767) | 2,260 hrs | 2,286 hrs |
| Total hrs last 90 Days | 182: 13 | 163 :40 |
| Total hrs last 60 Days | 104: 14 | 101 :55 |
| Total hrs last 30 Days | 60:13 | 19:50 |
| Total Last 7 Days | 12:19 | 13:22 |
| Accident Flight hrs (est.) | 4:38 | 4:38 |
| Hours On Duty Prior to Accident | 5:58 | 5:58 |
| Hours Off Duty Prior to Work Period | 120+ (5 days) | 120+(5 days) |
The captain began flying as a civilian student pilot in September 1963. He then joined the U.S. Air Force, became an Air Force pilot and flew a variety of military airplanes including fighters and 4-engine transport airplanes in domestic and foreign operations through 1969. He became employed by AA on September 22, 1969. Employment records at AA indicated that he had acquired about 2,698 flight hours before being hired, and all except 36 hours were with the U.S. Air Force. His service at AA began as a B-727 flight engineer. As flew as captain on the B-727, -757 and -767 [12].
The captain underwent his last proficiency check in a flight simulator on April 28, 1995. AA referred to this check as the "R2" check or the "simulator check." The check ended a S-day training and checking sequence in which other annual requirements were also met, including training regarding security and hazardous materials, crew resource management (CRM), and international operations. The captain completed annual line checks, administered by an AA FAA-approved check airman on November 9, 1995 (domestic) and on December 9, 1995 (international). In the line check on December 9, 1995, he flew as captain on AA965 from MIA to SKCL. Including flights to SKCL on December 9, and December 14, 1995, the captain flew a total of 13 times into Cali before the accident flight.
----------------
[12] The FAA awards common type ratings to pilots qualifying on the B-757 and -767 because of the similarities between the two airplanes. B-757/767 type rated pilots for AA and other airlines may serve on both airplane types equally, without need of additional certification.
The captain's last medical examination was on December 7, 1995, when his Class I medical certificate was renewed. His certificate bore the following limitation: "Holder shall wear lenses that correct for distant vision and possess glasses that correct for near vision while exercising the privileges of this airman certificate."
The captain was described by his colleagues as a non-smoker, avid tennis player, in exemplary health, and respected for his professional skills, including his skill in communicating with crewmembers and passengers. Company records contained numerous letters from passengers and company employees that reflected outstanding and courteous performance. The captain was married and had two adult children who lived outside of the home.
On the day of the accident, December 20, 1995, the captain arose around 0500. His wife began to prepare for a trip in her capacity as an AA flight attendant. She was later not sure whether the captain had returned to sleep after she departed their home at 0600. She estimated that he departed from home about 1200 for the drive to MIA.
The day prior to the accident, December 19, the captain awoke about 0700, and spent the day relaxing around the house and then playing tennis about l 1/2 hours with his wife. They returned home about 2130. From December 15 through 18, the captain and his wife visited his family in New Jersey, on what was described as an enjoyable Christmas visit that they took early because of the scheduled trips.
The first officer began his flying eareer as a college undergraduate by enrolling in the U.S. Air Force Reserve Officer Training Corps. He began pilot training with the Air Force in 1979, flying a variety of aircraft, including trainers and F-4E fighters, through 1986. He served as an instructor in ground school, in flight simulators, and in airplanes, and in 1985 was awarded Air Force Instruetor of the Year.
The first officer beeame employed by AA on Oetober 11, 1986. Company reeords indicated that he had accumulated a total of 1,362 flight hours when hired. He began as a flight engineer on the B-727. Later duties included first
officer on the B-727, McDonnell Douglas (MD) 11, and B-757 and -767. He possessed type ratings in the MD 11 and B757/B767.
The first officer attended the AA 5-day qualification and recurrence course and satisfactorily completed the required annual simulator check on November 27, 1995. As part of that sequence, annual recurrent requirements also ineluded training regarding security, hazardous materials, CRM, and international operations. The first officer's annual line cheek was aeeomplished on August 31, 1995.
The first offieer's Class 1 medical certificate was renewed on June 21, 1995, with no limitations.
The first officer had never flown into Cali. However, he had flown to other destinations in South America as an internationally qualified B-757/767 first officer.
The first officer was described by his colleagues as professionally competent, and appropriately assertive as a flightcrew member. He was married and the father of three young children who lived at home.
On the day of the accident, the first officer arose about 0700, and had breakfast with his family. Around 0830, he worked with his wife to prepare for their children's home schooling aetivities. He later exercised. He visited with his father and family around midday and, around 1230, left for the airport at Orlando, Florida, for the flight to MIA.
On the day prior to the accident, December 19, the first officer arose about 0700, and had an 0830, appointment with an aviation medical examiner (AME) for a flight physical [13]. Afterwards, the first officer visited with his brother at his brother's place of business, and later the two had lunch. The first officer returned home at 1530, and played basketball with his children. The family had dinner about 1730, and at 1900, he, his wife, and children attended a basketball game where their son was playing. The family returned home about 2015, and at 2115 the first officer helped put the children to bed. He and his wife watched television briefly and retired about 2330.
----------------
[13] The AME later stated that the first officer was found in excellent health.
On December 18, the first officer arose about 0715, and after breakfast exercised at the local YMCA. He assisted his wife in home schooling their children and then had lunch with his wife. After shopping for holiday gifts, they took the children to a restaurant for dinner and returned home about 2100.
The airplane, a Boeing 757-223, serial no. 24609, was operated by AA since new on August 27, 1991. The airplane was owned by Meridian Trust Company of Reading, Pennsylvania, U.S.A., and leased to the airline.
Before the accident flight, the airplane accumulated 13,782 flight hours and 4,922 cycles. The airplane was equipped with two RB-211 535E 4B Rolls Royce turbofan engines. The left engine, serial no. 31146, accumulated 10,657 hours and 3,768 cycles. The right engine, serial no. 31042, had accumulated 13,274 total hours and 4,966 cycles.
There were no malfunctions or outstanding maintenance items on the airplane prior to its departure from MIA on December 20, 1995. The airplane received a B-level maintenance check (B-check) in November 1995, and all subsequent required maintenance checks were performed. In addition, there was no record of repetitive navigation or flight control system anomalies.
The airplane weight and balance was determined by AA's dispatch center at Dallas/Ft. Worth International Airport (DFW), Texas, U.S.A. The airplane was loaded with 43,300 pounds of fuel for takeoff from MIA on December 20, 1995. Its takeoff gross weight was calculated as 209,520 pounds. The airplane's center of gravity (c.g.) at takeoff was determined to be 25.2 percent mean aerodynamic chord (MAC). The gross weight and c.g. were within limits for takeoff.
Estimated flight plan calculations indicated that the airplane consumed 26,620 pounds of fuel prior to impact. Its impact gross weight was 182,900 pounds and its c.g. was 23.8 percent MAC. The final gross weight and c.g. were within landing limits.
The B-757 and -767 are flight management system (FMS)-equipped airplanes. The accident airplane incorporated an FMS that included an flight management computer (FMC), a worldwide navigation data base that contained radio frequencies, and latitude and longitude coordinates of relevant navigation aids as well as coordinates of airports capable of B-757 operations. The FMC data base also included B-757 performance data which, combined with pilot inputs, governed autothrottle and autopilot functions. The FMS monitored the system and engine status and displayed the information, as well as airplane attitude, flightpath, navigation, and other information, through electronically-generated cathode ray tube (CRT) displays [14].
Pilot input into the FMS could be performed either through a keyboard and associated cathode ray tube (CRT), known as a control display unit (CDU), or through more limited FMS input via controls on the glareshield (see section 1.16, regarding post-accident testing of FMS components).
The flight crew received the following AA terminal weather forecast for Cali in the flight dispatch records:
Cali at 0606 universal coordinated time (utc) [15]: Winds calm, visibility more than 10 kilometers, clouds scattered at 2,500 and 10,000 feet
Temporary change (Cali) from 0900 to 1300 utc: 8000 meters visibility, rain showers in the vicinity, clouds scattered at 2,000, broken at 8,500 feet
Temporary change (Cali) from 2000 through 0200 utc: Winds 360 degrees at 05 knots, rain showers in the vicinity, clouds scattered at 2,000 feet and broken at 8,000 feet
The flight departure paper recorded the weather at 1500 est as: Winds calm, visibility more than 10 kilometers, clouds scattered at 2,000 and 12,000 feet,
----------------
[14] On the instrument panel before each pilot
[15] Universal coordinate time. Est is 5 hours behind utc.
temperature 28 centigrade, dew point 18 degrees centigrade (C.), altimeter (QNH) 29.94 inches of mercury
The flight crew received an updated weather message via the ACARS. The weather was for 1700 est and was reported as:
(Cali): Winds 340 degrees at 06 knots, visibility more than 10 kilometers, rain showers in the vicinity, clouds scattered at 1,700 feet and broken at 10,000 feet, temperature 28 degrees C., dew point 18 degrees C., altimeter (QNH) 29.98 inches of mercury
Enroute, the flight crew requested the Cali weather via ACARS at 2050 est. The company replied at 2051, via ACARS, that there was "no current data."
At 2110 est, the flightcrew requested, again, the weather for Cali. At 2111, the flightcrew received via the uplink, the following weather information for 2000 local at Cali: Winds 160 degrees at 04 knots, visibility more than 10 kilometers, clouds scattered at 1,700 and 10,000 feet, temperature 23 degrees and dew point 18 degrees C., altimeter (QNH) 29.98 inches of mercury. This was the last request and uplink of weather recorded.
There were no difficulties with aids to navigation.
There were no difficulties with communications equipment.
Alfonso Bonilla Aragon Airport (SKCL) in Cali, is located in a long, narrow valley oriented north to south. Mountains extend up to 14,000 feet msl to the east and west of the valley. The airport is located approximately 7.5 miles north of CLO, at an elevation of 3,162 feet msl.
At the time of the accident, the airport control tower operated 24 hours a day, controlling departing and arriving traffic to runways 01 and 19. The runway was hard surfaced, 9,842 feet long, and 148 feet wide, with a parallel taxiway running the full length. Runway 01 had instrument landing system (ILS) CAT 1 and VOR/DME approaches available. The ILS has a 2.5 degree glide slope, with precision approach path indicator (PAPI) visual glide path lighting to match the 2.5 degree electronic glide slope. Runway 19 had a VOR/DME approach available and the lighting included a PAPI system with a 3.0 degree glide path. Two standard arrivals (STARs) were available, one from the north of the airport (ROZO 1) and one from the east (MANGA 1). There were 12 published departures available.
Radio navigation facilities included the ILS (IPAS), the Cali VOR (CLO), Rozo NDB (R), the middle marker (AS), and the Cali NDB (CLO). The Tulua VOR (ULQ) was approximately 33 nautical miles north of the airfield (43 DME from CLO), and was the initial point depicted on the ROZO 1 arrival.
The airport was served by Cali Approach. No approach control radar was available.
The field report recorded in the AA dispatch records indicated that runways 01 and 19 were open and dry. There were three notices to airmen (NOTAMS) in the flight departure papers, they were:
1. Until further notice, runway 01 LM/AS frequency 240 Mhz ops on test period.
2. Fire and rescue services downgrades to VII cat.
3. Until further notice, MER/NDB 1.685 Khz inop.
The airplane was equipped a Sundstrand digital FDR, serial no. 6707. FDR recorded parameters included: pressure altitude; radio altitude; magnetic heading; computed airspeed; pitch attitude; roll attitude; engine status; navigation mode; indicated airspeed; autothrottle and autopilot parameters; ground proximity warning alerts; and parameters indicating flight control position, including speed
brake deployment. The data were recorded on a continuous 25 hour cycle in which the oldest data were erased and new data recorded.
The FDR was extensively damaged by impact forces. There was no evidence of fire damage to the recorder. The tape recording medium was undamaged. The FDR was brought to the U.S. National Transportation Safety Board's (NTSB's) laboratories in Washington, D.C., U.S.A., and read out.
The airplane was equipped with a Fairchild model A-lOOa CVR, serial no. 59225. Examination in the NTSB CVR laboratory found exterior structural damage. The exterior case was cut away to access the tape medium. The tape did not sustain heat or impact damage. The recording was of good quality and a transcript was prepared of the entire 30:40 minute recording.
The airplane struck near the top of a mountain ridge about 35 miles northeast of Cali. The elevation of the top of the ridge was about 9,000 feet mean sea level. The airplane initially struck trees on the east side of the ridge, and the preponderance of the wreckage, which contained the occupants of the airplane and included both engines, came to rest on the west face of the ridge. There was no indication of in-flight fire or separation of parts before initial impact.
The initial impact area was marked by an area of broken trees, followed by a swath where the trees had been essentially flattened or uprooted. The area of uprooted trees began about 250 feet below the top of the ridge. The initial impact swath was oriented along a heading of about 220°. Wreckage that was found at the beginning of the wreckage path included thrust reverser parts, a fan cowling, an APU tail cone, flap jackscrews, an engine fire bottle, the FDR, and a small section of wing. The pattern of the broken trees indicated that the airplane initially struck at a high nose up attitude.
The main wreckage came to rest on the west side of the ridge, about 400 to 500 feet from the top. In addition to the engines, the largest portion of wreckage included the cockpit, a section of center fuselage about 35 feet long, the CVR, aviation electronics (avionics) boxes, a section of the aft fuselage, and a portion of the wing center section.
The wreckage evidence indicated that both flaps and landing gear were in the retracted position at the time of impact.
Both engines were examined on site. The left engine showed ingestion of soil and foliage as far aft as the inlet guide vanes to the intermediate compressor section. There was a substantial bending of fan blades in a counter-clockwise direction, with some bent clockwise.
The right engine was found slightly buried into the ground. The blade damage that was observable was similar to the damage observed on the left engine. Soil and foliage were found as far aft as the inlet to the intermediate compressor section. Neither engine showed evidence of fire damage.
Numerous cireuit cards and other parts that were onsidered likely to contain non-volatile memory were retrieved from the site, packed in static free material, and shipped to the United States for read out at the facilities of their manufacturers. With the exception of one circuit card from the Honeywell- manufaetured FMC, the material either did not contain non-volatile memory or was too severely damaged to permit data retrieval. Discussion of the data retrieval of the non-volatile memory from the FMC is located in section 1.16, Tests and Research.
The body of the first officer was recovered on the first day after the accident. The body of the captain was retrieved from the crash site on the third day after the accident. The cause of death of each was determined to be blunt force trauma.
Specimens of liver, blood, and vitreous humor were obtained and analyzed by the Colombian Instituto Nacional de Medicina Legal. The samples from the body of the first officer were found to be negative for alcohol and drugs of abuse. The blood and liver samples from the captain were found to be positive for alcohol at 0.074 percent and 0.35 percent blood alcohol levels, respectively, and negative for drugs of abuse. Vitreous specimens were found to be negative for both pilots.
Portions of the liver and blood samples from the bodies of the flightcrew members were then flown to the United States to be further analyzed by
the Forensic Toxicology Laboratory of the U.S. Armed Forces Institute of Pathology. The analysis and subsequent reexamination of the results of the analysis in Colombia indicated that the positive alcohol level derived from post-mortem microbial action, and not from pre-mortem alcohol ingestion.
The was no evidence preimpact fire or explosion. There was limited postimpact fire, where the main fuselage came to rest.
Search and rescue facilities coordinators around the Cali and Buga area were notified of the missing flight at 2150 local time. At 2230, the Civil Defense, Red Cross, Police and Army contingencies were mobilized to the Buga general area where the airplane was last reported. The initial sighting of the crash site was made by a helicopter at 06:30, December 21, 1995. Search teams arrived by helicopter to the crash site within a few minutes of the sighting.
The characteristics and magnitude of the impact and subsequent destruction of the airplane indicated that the accident was non survivable. However, 5 passengers initially survived the crash, having sustained serious injuries. One died later in the hospital.
Postmortem examination of the occupants indicated that the characteristics of the fatal and non fatal injuries varied according to the location of the persons in the crashed airplane. All of the injuries were consistent with deceleration trauma of different intensity consistent with the aircraft's impact and breakdown pattern. Because some passengers were found to have changed seats within the airplane, evaluating individual injuries by seat assignment was not successful.
Follow-up examinations and testing were conducted regarding aircraft systems, operations procedures, and human performance. These were conducted in the United States at Flight Safety International Academy in Miami, Florida; Honeywell Air Transport Systems, in Phoenix, Arizona; Jeppesen Sanderson
Company, in Englewood, Colorado; American Airlines in Fort Worth, Texas; and Boeing Commercial Airplane Group, in Seattle, Washington.
Portions of the FMS, including the FMC, that had been recovered from the wreckage, were examined at Honeywell Air Transport Systems.
After the components were cleaned for laboratory examination, it was found that the FMC contained a printed circuit card that had two non-volatile memory integrated circuits. Data recovered from the integrated circuits included a navigation data base, guidance buffer, built in test equipment (BITE) history file, operational program, and other reference information.
A load test of the FMC memory showed that the operational software and navigational data were current for the time of the accident. The BITE showed that there had been no recorded loss of function during the last 10 flights of the airplane.
The guidance buffer recorded that the FMC-planned route of flight at the point of power loss [16] was from the last passed waypoint, shown as KILER, direct to the next waypoint that had not yet been passed, shown as ULQ. The route beyond ULQ was shown as waypoint R, then CLO, then CLO03 [17], then the stored ILS runway 01 approach of CI01, then FI01, then RW01, then ROZO, then a hold [18] at ROZO.
When the FMC memory was first restored, a modification to the above route was displayed. The modified route was shown as ULQ, a ROUTE DISCONTINUITY message, then R, another ROUTE DISCONTINUITY message, then CLO, then CLO03, then CI01, then FI01, then RW01, then ROZO, then a hold at ROZO.
The FMC was put through a short term (power transient) initialization and the captain's and first officer's CDU displays were identical, as follows:
----------------
[16] Coinciding with the time of impact.
[17] CLO03 was found to be a point-bearing distance location.
[18] BITE provided non volatile memory of FMC activity for previous 10 flights of the accident airplane. Hold indicates routing to a preplanned holding pattern location.
| MOD RTE 1 LEGS | 1/2 | |
| 066° | ||
| R | 268/FL364 | |
| THEN | ||
| IIIIII | ||
| --ROUTE DISCONTINUITY - | ||
| CLO | 237/5510 | |
| 161° | 3NM | |
| CLO03 | 207/5190 | |
| 307° | 2NM | |
| CI01 | 189/5000 | |
| <ERASE | RTE DATA> |
The CLO03 was not seen on a printed format of the route. When the (L4) line select key (LSK) for CLO03 was pressed, the scratch pad area (LSK L6) at the bottom of the screen was displayed:
Pushing the NEXT PAGE button showed:
| MOD RTE LEGS | 2/2 | |
| 013° | 2NM | |
| FI01 | 170/5000 | |
| 013° | 7NM | |
| RW01 | 130/3200 | |
| 013° | 4NM | |
| ROZO | ---/3560A | |
| HOLD AT | ||
| ROZO | ---/5000 | |
| <ERASE | RTE DATA> |
----------------
[19] The font size on the airspeeds and altitudes associated with CLO
and CLO03 were smaller than the font sizes of comparable information
for CI01. These differences indicate that the information for CI01 was
inputted by the pilot whereas the information for CLO were generated
by the FMS.
REF NAV DATA was displayed for the following points:
| IDENT | LAT | LONG | FREQ | MAG |
| VAR ELEV | ||||
| ULQ | N04degO5.8 | W076degl3.6 | 177.70 | W1 |
| CLO | N03deg24.2 | W076deg24.6 | 115.50 | W2 |
| 3300ft | ||||
| CLO03 | N03deg21.4 | W076deg23.6 | ||
| CI01 | N03deg22.5 | W076deg25.0 | ||
| FI01 | N03deg24.5 | W076deg24.7 | ||
| RW01 | N03deg31.6 | W076deg23.2 | LENGTH=9842ft | |
| 3150ft | ||||
| ROZO | N03deg35.8 | W076deg22.5 | ||
| R | N04deg40.7 | W074deg06.3 [20] | ||
| SKCL | N03deg32.8 | W076deg23.1 | ||
| 3160ft | ||||
| KILER | N15deO0.0 | W076deg52.0 |
All of the above points were within 0.1 mile of their location in the ARINC-424 [21] navigational data for December 21, 1995, with the exception of RW01 at SKCL. However, it was found that the FMC display showed the threshold of the runway and the ARINC-424 data showed the touch-down point for the instrument landing system.
During testing at Honeywell Systems, the memory card from the accident airplane was installed into an FMC that was programmed in the AA configuration and run on an engineering simulator. Different route modifications were executed and timed for delays after the EXECUTE button was pushed. Over ULQ, inputting "direct" changes to ROZO from different orientations, as well as to KILER, resulted in execution delays of not more than approximately 2 seconds (see appendix E, Reconstructed Route Pages from accident FMC).
At the completion of the tests, the memory card was returned to the original FMC computer case that had been recovered from the accident site. Dirt
----------------
[20] R refers to an NDB in Bogota, located about 130 miles
east-northeast of Cali.
[21] Aeronautical Radio. Inc. of Annapolis, Maryland).
was vacuumed from the interior of the FMC and brushed from the faces of dirty circuit cards. Although a number of connector pins were found broken from the dented rear face, they were then box mounted into the simulator without difficulty and operated successfully.
The Jeppesen Sanderson Company described that software inputs that are provided by contract to operators of FMS-equipped aircraft are made in accordance with the guidelines of ARINC-424 Chapter 7, "Naming Conventions, " establishes the coding rules of identifiers and Name fields when government source data does not provide these Identifiers or Names within the rules established by International Civil Aviation Organization (ICAO) Annex 11. As stated by the Jeppesen Sanderson Senior Vice President, Flight Information and Technology, in a subsequent letter to the President of the Investigation:
An important item to remember is that all of Jeppesen's navigation data is entered into our database using the ARINC 424 Aeronautical Database Specifications standard. This standard is the result of an effort that began in August 1973 and has been continuously updated and now is in its 14th revision. The ARINC spec is a set of rules that has been established by industry, airlines, avionics manufacturers, FAA, ICAO, international AIS offices, and others to ensure agreement in concept of using aeronautical information in automated systems worldwide.
As one of the first considerations, databases cannot accept duplicate information. There cannot be two names for the same item. Specifically, the Romeo NDB uses the letter R for its identifier. The Rozo NDB also uses the same letter R for its identifier. The letter R was assigned to both of these navaids by the Colombian government.
Both of these navaids are within the same country and therefore have the same ICAO identifier. For enroute facilities, the combination of both the NDB identifier and [emphasis in original] the ICAO code is normally adequate to provide uniqueness for entering data in the database.
When entering navaid information into the database, the navaid identifier is used as the key identifier. This means that the letter R is the default value for the Romeo NDB and the Rozo NDB. Since the Bogota city and airport is larger than Cali, the larger airports are entered sequentially at the beginning to satisfy the greatest amount of users. The letter R was entered for the Romeo NDB as the "key" to the navaid. Therefore, when using most FMSs, entering the letter R when in Colombia will call up the Romeo NDB since it is the identifier for the Romeo NDB.
When the Rozo NDB was entered into the database, the letter R was attempted, but the computer rejected the letter R since it had already been used for the Romeo NDB. According to the ARINC 424 standards, when a duplicate exists, the name of the NDB can be used as the identifier for entry into the database. In the case of Rozo, since the name is four letters or less, the complete name of Rozo was used as the identifier. At Jeppesen, we are not experts on the use of FMSs, but we understand the access to NDBs in most FMSs is via their identifier. In this case, an entry of the single letter R would retrieve Rome since R is the identifier for Romeo. To retrieve the Rozo NDB, the letters ROZO would need to be entered into the FMS since that is the identifier for Rozo.
Under the NavData tab in the Jeppesen Airway Manual, there is an explanation of most of the procedures specified in ARINC 424 as they apply to the user of an FMS....
Following the examinations at Honeywell Systems and the meehngs at Jeppesen Sanderson, tests were conducted at Boeing Commercial Airplane Group, using a B-757 fixed base simulator as well as a CDU/FMS bench-type simulator. Several different displays were used to replicate the flightpath and routing information that was recovered from the accident FMC non volatile memory at Honeywell Systems, and the accident flight's arrival, descent, approach phase, and attempted escape maneuver were replicated as closely as possible on the fixed-base simulator.
It was found that neither the Boeing fixed base simulator nor the CDU/FMS simulator could be backdriven with the data obtained directly from the accident airplane's FDR. Instead, data obtained from the FDR and non volatile memory data from the FMC were input into both simulators, to replicate the flight as closely as possible from 63 miles north of CLO to and including the escape maneuver. It was found that calling up R on the CDU displayed a series of waypoints and their coordinates. They were located north and south of the equator and ordered from top to bottom of the display by their distance from the airplane. Romeo, a non directional radio beacon (NDB) in the City of Bogota, was the first and closest waypoint displayed. Rozo, which was also an NDB, was not displayed, and entering R would not call up Rozo. Rozo could only called up by spelling out ROZO on the CDU.
The Simulations found that when R was entered into the CDU, a white dashed line pointed off the map display towards the east-northeast. When R was "executed," the airplane turned towards R (in the City of Bogota) and the white dashed line turned to a solid magenta colored line on the display.
Investigators also attempted to replicate the GPWS escape maneuver, particularly because wreckage examinations and FDR data indicated that the speedbrakes were not retracted during the escape maneuver. Because the B-757 flight simulators could not be back driven during the tests, it could not be determined with precision whether the airplane would have missed the mountain/tree tops if the speedbrakes had been retracted during the escape attempt.
AA began operating its Latin American routes in July 1991, and the MIA crew base opened at that time. At the time of the accident, the MIA base was third in terms of the number of pilots, behind DFW and Chicago-O'Hare International Airport (ORD). The accident flightcrew members were based at MIA. On AA's Latin American and Caribbean routs, 98.4 percent of the flightcrews were based at MIA.
The MIA base was overseen by a base manager who was a B-757/767 captain in their South American division. He had been a line pilot until approximately one year before the accident. AA's Latin American operations and domestic operations from MIA were each overseen by their own chief pilot.
Pilots based at MIA reported to the base manager. He was supervised by the Assistant Vice President, Line Operations., who reported to the Vice President, Flight Operations. He was supervised by the Executive Vice President, Operations, who reported to the President of AA. The President was responsible to the Chief Executive Officer of the airline.
Upon entering Colombian airspace on December 20, 1995, AA965 was under the control of the Barranquilla Center, and then Bogota Center. Upon exiting the limits of the Bogota Center airspace, the airplane entered the airspace controlled by Cali Approach.
At the time of the accident, the Cali approach control facility was located in the control tower at SKCL. The approach controller was located in a small cab 8 to 10 feet from the tower controller. Flight progress strips were used to keep track of aircraft that were inbound or outbound from the airport, or traversing the Cali airspace. Radar coverage and radar services were not available.
Colombian controllers operate under rules promulgated by the Aeronautica Civil Communications. Pilots are governed by Annex 10 to the Convention on International Civil Aviation, "Aeronautical Telecommunications." The annex establishes the rules under which pilots and controllers, who are not conversant in each other' s native language, can communicate. Section 1.2 of Annex 10 states:
The primary means for exchanging information in air-ground communications is the language of the ground stations, which will in most cases be the national language of the State responsible for the station.
Paragraph 5.2.1.1 2 recommends, that where English is not the language of the ground station the English language should be available on request, thereby, the recommendations of the Annex indicate that the English language will be available as a universal medium for radiotelephone communications.
Section 1.4 of the Annex adds:
That means of assuring safety, however, can hardly be satisfactory in practice. It is always possible that an emergency may require communication with a ground station not foreseen in the original planning, and that the handicapping or prevention of such emergency communications by the lack of a language common to the flightcrew and the ground station could lead to an accident.
In the Latin American Pilot Reference Guide that AA provided to its Latin American division pilots, the following guidance was given:
Because the controller may not understand any comments that are unexpected, out of sequence, or not in the ICAO format, you should use only ICAO accepted radio-telephony terminology.
Colombian rules included the following:
If a clearance given by the air traffic control center is not satisfactory to the pilot of the aircraft, the pilot can request an amended clearance, and if possible, he will receive an amended clearance.
The air traffic controller, who was on duty at the time of the accident, in his first interview indicated to investigators that there were no language difficulties in the communications between himself and the accident flightcrew. However, in a second interview, when asked a specific question regarding his opinion about the effects the difference in native languages between the accident flightcrew and approach control may have had, he stated that he would have asked the pilots of AA965 more detailed questions regarding the routing and the approach if the pilots had spoken Spanish. He stated that he believed that his comprehension of the pilot's transmission was satisfactory and that the pilot also understood him. The controller said that, in a non-radar environment, it was unusual for a pilot to request to fly from his or her present position to the arrival transition. The air traffic controller also stated that the request from the flight to fly direct to the Tulua VOR, when the flight was 38 miles north of Cali, made no sense to him. He said that his fluency in non-aviation English was limited and he could not ask them to elaborate on the request. Rather, he restated the clearance and requested their position
relative to the Cali VOR. He believed that the pilot's response, that AA965 was 37 miles from Cali, suggested that perhaps the pilot had forgotten to report passing the Tulua VOR.
The controller further stated that had the pilots been Spanish-speaking, he would have told them that their request made little sense, and that it was illogical and incongruent. He said that because of limitations in his command of English he was unable to convey these thoughts to the crew.
At the time of the accident, FAA oversight of AA's operations into Latin America was the carried out by its Flight Standards District Office (FSDO) No. 19, based at MIA. The FAA office responsible for overall surveillance of AA was based near the airline's headquarters in at DFW. FSDO 19 was the largest FSDO in the United States, responsible for the oversight of 11 carriers operating under 14 Code of Federal Regulations (CFR) Part 121, 51 carriers under Part 135, 12 flight schools operating under Part 141, 233 repair stations operating under Part 145, as well as several other certificates. FSDO 23, also based at MIA was responsible for surveillance of Part 129 foreign carriers operating into MIA. Under a memorandum of understanding (MOU) with FSDO-19, FSDO-23 accomplished some of the surveillance of U.S. carriers operating into Latin America. FSDO 19 was responsible for performing geographic surveillance of AA surveillance as well as surveillance of United Airlines and Continental Airlines operations into Latin America and the Caribbean. AA management personnel described the FAA presence at MIA as positive and cooperative.
During post accident interviews, FAA personnel indicated that AA conducted about 1,870 of the 7,200 weekly operations at MIA, and that enroute surveillance of operations into South America were often conducted by airworthiness inspectors who were already traveling to Latin America to perform facility inspections. Airworthiness inspectors would plan and conduct enroute inspections on flights to South America, inspect the facility at the destination, and conduct enroute inspections on the return trip. Inspections were planned in this manner to reduce the FAA expenses associated with overseas travel. During interviews, FAA personnel verified that operations inspectors, who perform cockpit enroute checks are given different FAA training than airworthiness inspectors. Airworthiness inspectors specialize in maintenance matters and are not qualified flightcrew operational evaluators.
International Civil Aviation Organization (ICAO) document no. 8335, Chapter 9, part 9.4.1 states:
Ideally a CAA inspector should be at least as qualified as the personnel to be inspected or supervised. To carry out in-flight inspections, a CAA inspector should not only be qualified in the type of aircraft used but also possess appropriate route experience.
Part 9.6.33 states:
The following guidelines are suggested as minimum requirements with respect to the frequency of conducting the various inspections.
| Type | Frequency |
| En-route inspection | quarterly |
Three operations inspectors at FSDO-19 performed 1,807 flight checks, including simulator, oral or actual airplane checks, out of 3,400 requests.
AA provided additional ground school instruction to all flightcrew members who were to begin operations into Latin America. This followed a 2-day ground school for all pilots who were to begin flying international routes. In the Latin America training, the airline also distributed to students a Jeppesen-sized reference guide devoted exclusively to the hazards and demands of flying into Latin America. Pilots also participated annually AA provided CRM training, exclusive to Latin American flight operations. The training and reference guide were not required by Federal Aviation Regulations (FARs).
The following were among the title of topics addressed in both the reference guide and initial ground school training:
In addition, the introduction to the reference guide included the following guidance:
Flights into Latin America can be more challenging and far more dangerous than domestic flying or the highly structured North Atlantic/European operation. Some Latin American destinations have multiple hazards to air operations, and ATC facilities may provide little assistance in avoiding them.
Enroute and terminal radar coverage may be limited or non-existent. Mountains, larger and more extensive than anything you've probably ever seen, will loom up around you during descent and approach, and during departure. Communications, navigation, weather problems, and an Air Traffic Control philosophy peculiar to Latin America may conspire with disastrous consequences.
There are many hazards in this environment, but the greatest danger is pilot complacency. From 1979 through 1989, 44 major accidents involving large commercial aircraft occurred in South America. Of these 44 accidents, 34 were attributable to pilot error, or were pilot-preventable with proper situational awareness (emphasis in original).
The speedbrake system in the B-757 consists of overwing control surfaces that extend and retract at the command of the pilot through the aft and forward movement of the speedbrake control lever located in the top left side of the center control stand. In flight operation of the speedbrake system is manual. Automatic extension and retraction are restricted to the landing phase and is activated upon main wheel touchdown and forward movement of the power levers respectively. Due to the limited aerodynamic effect of the speedbrakes, flightcrews may become unaware that they are in the extended mode. Annunciation of speedbrake deployment only becomes activated in landing configuration and / or below 800 feet. (see appendix D, Aileron and Spoiler Controls)
The Ground Proximity Warning Escape Maneuver procedure was contained in American Airlines B-757 Flight Operations Manual under the section entitled, "Instruments." The procedure addressed the flightcrew actions that must be carried out in order to attain maximum climb performance of the airplane in order to overcome the obstacles ahead of its flight path. These pilot actions include the dlsengagement of autopilot and autothrottle system as well as selecting maximum power and attaining best angle of climb.
There was no evidence of failures or malfunctions in the airplane, its components, or its systems. Weather was not a factor in this accident. Both crewmembers were properly qualified and certificated to operate the airplane on this flight. The specific details of the training history of the accident flightcrew was not available to the accident investigation team, because of the AA policy of maintaining training records which indicate only pass/fail on evaluations. No evidence was found that either crewmember was experiencing a behavioral or physiological impairment at the time that could have caused or contributed to of the accident.
The evidence indicates that AA965 continued on the appropriate flight path until it entered the Cali Approach airspace. After contacting the Cali approach controller, the flightcrew accepted the controller's offer to land on runway 19 at SKCL, rather than runway 01 per the flight planned route. After receiving clearances to descend, lastly to 5,000 feet msl, neither flighterew member made an attempt to terminate the descent, despite the airplane's deviation from the published approach course, in a valley between two mountain ridges. After the flightcrew recognized that the airplane had deviated from the prescribed inbound course, as the first offieer stated less than 1 minute prior to impact, they attempted to turn back to the "extended centerline" of the runway, which as the eaptain then stated, "...is Rozo." The accident occurred following the turn back to the right from a track to the east of the prescribed course and an attempt to fly in a southwesterly heading to directly intercept the extended runway centerline.
The investigation examined flightcrew actions to determine how a properly trained and qualified crew would allow the airplane to proceed off course, and continue the descent into an area of mountainous terrain. In addition, the investigation examined the actions of the Cali approach controller to determine what role, if any, his actions may have had upon the accident. The quality of the FAA surveillance of the AA South American operation was examined. The investigation also assessed survivability issues to determine the extent to which the number of the injuries and fatalities could have been reduced, and the design of the speedbrake, and AA's procedures and training in retracting speedbrakes during GPWS escape maneuvers..
The evidence indicates that the captain and first officer committed a series of operational errors that led to the accident. The errors, which individually were not causal, interacted in a way that caused the accident. The CVR contained the final approximately 30 minutes of cockpit voice recording, but did not contain details of an approach briefing into Cali, and investigators were unable to determine whether or how detailed a flightcrew approach briefing took place before the beginning of recorded information. However, investigators were able to identify a series of errors that initiated with the flightcrew's acceptance of the controller's offer to land on runway 19 rather than the filed approach to runway 01. This expectation was based on the experience of AA pilots operating into Cali, where almost all landings had been on runway 01, and AA's operations office at SKCL had radioed the accident flightcrew about 5 minutes prior to the controller's offer information regarding the active runway. Also, FMC reconstruction found that the ILS approach to runway 01 had been entered into the airplane's FMS.
The CVR indicates that the decision to accept the offer to land on runway 19 was made jointly by the captain and first officer in a 4-second exchange that began at 2136:38. The captain asked: "would you like to shoot the one nine straight in?" The first officer responded, "Yeah, we'll have to scramble to get down. We can do it." This interchange followed an earlier discussion in which the captain indicated to the first officer his desire to hurry the arrival into Cali, following the delay on departure from MIA, in an apparent attempt to minimize the effect of the delay on the flight attendants' rest requirements. For example, at 2126:01, he asked the first officer to "keep the speed up in the descent."
As a result of the decision to accept a straight in approach to runway 19, the flightcrew needed to accomplish the following actions expeditiously:
The evidence of the hurried nature of the tasks performed and the inadequate review of critical information between the time of the flightcrew's acceptance of the offer to land on runway 19 and the flight's crossing the initial approach fix, ULQ, indicates that insufficient time was available to fully or effectively carry out these actions. Consequently, several necessary steps were performed improperly or not at all and the flightcrew failed to recognize that the airplane was heading towards terrain, until just before impact. Therefore, Aeronautica Civil believes that flightcrew actions caused the accident.
Researchers studying decision making in dynamic situations [22] have suggested that experienced persons can quickly make decisions based on cues that they match with those from previous experiences encountered in similar situations. A referenced text refers to this characteristic as Recognition Primed Decision Making, in which a decision maker's rapid assessment of the situation is almost immediately followed by the selection of an outcome. It states:
Our research has shown that recognitional decision making is more likely when the decision maker is experienced, when time pressure is greater, and when conditions are less stable. [23]
It is likely therefore that when previously faced with similar situations, such as the opportunity to execute an approach that was closer to the airplane's
----------------
[22] Klein, G., (1993), Naturalistic Decision Making: Implications for
Design. Wright-Patterson Air Force Base, Ohio: Crew System Ergonomics
Information Analysis Center.
[23] Klein, G., (1993), A recognition primed decision (RPD) model of rapid decision making. In Klein, G. A., Orasanu, J., Calderwood, R., and Zsambok, C. E., (Eds.), Decision Making in Action: Models and Methods. Norwood, New Jersey, Ablex, p. 146.
position than the approach anticipated, the pilots of AA965, each of whom had acquired years of experience as air transport pilots, accepted the offers and landed without incident.
However, recognition primed decision making can present risks to the decision maker if the initial assessment of the situation is incorrect, or if the situation changes sufficiently after the decision has been made but the initial decision is not reconsidered. In this accident, the latter scenario appears to have been the case; there is no evidence that either flightcrew member reconsidered the initial decision to accept the offer to land on runway 19 and all subsequent actions were directed to completing the steps necessary to successfully land.
The evidence suggests that either of two reasons could account for the flightcrew's persistence in attempting to land rather than discontinuing the approach. These include the failure to adequately consider the time required to perform the steps needed to execute the approach and the reluctance of decision makers in general to alter a decision once it has been made.
The CVR transcript indicates that the captain, at 2137:10, gave the only consideration either flightcrew member expressed in reference to the time available, after accepting the offer to land on runway 19, when he asked the first officer, in response to an ATC clearance, "Yeah he did [say the Rozo 1 arrival]. We have time to pull that [approach chart] out?" There is no response to this question, but the CVR records the sound of "rustling pages," likely the approach chart. Despite this comment, there is no evidence that either pilot acknowledged that little time was available to perform the preliminary tasks such as verifying their position relative to the navaids that formed the basis for the approach or to execute the approach.
Once they began to prepare for the approach to runway 19, there is no evidence that the flightcrew revisited the decision, despite increasing evidence that should have discontinued the approach. This evidence, supported by recovered FMC non volatile memory, includes the following:
By not reconsidering that initial decision, the flightcrew acted consistently with the findings of human factors research on decision making that found that decision makers are reluctant to alter a decision after it has been made. For example [24]:
Operators tend to seek (and therefore find) information that confirms the chosen hypothesis and to avoid information or tests whose outcome ... could disconfirm it. This bias produces a sort of "cognitive tunnel vision" in which operators fail to encode or process information that is contradictory to or inconsistent with the initially formulated hypothesis. Such tunneling seems to be enhanced particularly under conditions of high stress and workload.
Thus, in addition to simply being too busy to recognize that they could not properly execute the approach, once the decision to land on runway 19 had been made, the course of action taken was to continue the approach, rather to consider discontinuing it.
Once they made the decision to accept the offer to land on runway 19, the flightcrew displayed poor situation awareness, with regard to such critical factors as the following:
The flightcrew's situation awareness was further compromised by a lack of information regarding the rules which governed the logic and priorities of the navigation data base in the FMS.
----------------
[24] Wickens, C. D., (1984), Engineering Psychology and Human
Performance. Columbus, Ohio: Charles E. Merrill, p. 97.
Situational awareness has been defined [25] as the:
...perception of the elements in the environment within a volume of time and space, the comprehension of their meaning, and the projection of their status in the near future.
To airline pilots, situational awareness refers to a flightcrew's understanding of the status and flightpath of the aircraft, and the accuracy of their prediction about its future status and flightpath. Deficiencies in situation awareness can lead to potentially catastrophic failures involving flightpath prediction or comprehension and prediction of system parameters.
The accident CVR indicated that from the beginning of their attempt to land on runway 19, the flightcrew exhibited a lack of awareness of fundamental parameters of the approach. From 2137:11, when the sound of rustling pages can be heard, the flightcrew attempted to both review the approach and determine the airplane's present and predicted position in reference to critical points on the approach. Their inability to effectively do both tasks is evidenced at 2138:49, when the first officer asked, "where are we," followed by a short discussion between both the captain and first officer regarding their position relative to the ULQ VOR. Again at 2139:30, two minutes before impact, neither flightcrew member could determine which navaid they were to proceed towards. The first officer stated, "left turn, so you want a left turn back around to ULQ." The captain replied, "Nawww... hell no, let's press on to..." The first officer stated, "well we're, press on to where though?" The captain replied, "Tulua." The first officer staid, "that's a right u u. The captain stated, "where we goin'? one two.. come to the right. let' go to Cali first of all, lets, we got [expletive] up her didn't we." The first officer replied, "yeah."
The captain established the flightpath that initially led to the deficiency in situational awareness by misinterpreting the Cali approach controller's clearance to proceed to Cali, given at 2134:59, as a clearance "direct to" Cali. The captain's readback of the clearance, "... understood. Cleared direct to Cali VOR. Report Tulua ... " received an affirmative response from the controller. The captain's readback was technically correct because he stated that he was to report Tulua, thus requiring him to report "crossing" the fix first. However, the CVR indicates that the
----------------
[25] Endsley, M R. (1995). Toward a theory of situation awareness in dynamic
systems. Human Factors, 37, 65-84, p. 36.
captain then executed a change in the FMS programmed flightpath to proceed "direct to" the Cali VOR. In so doing he removed all fixes between the airplane's present position and Cali, including Tulua, the fix they were to proceed towards.
There is no evidence in the CVR transcript that either pilot recognized that ULQ had been deleted from the display until they were considerably closer to Cali, and were in fact past ULQ at that time. Consequently, largely as a result of this action, the flightcrew crossed the initial approach fix ULQ, without realizing that they had done so and without acknowledging the crossing to the controller. Aeronautica Civil believes that the logic of the FMS that removed all fixes between the airplane's present position and the "direct to" fix compromised the situational awareness of the flightcrew. In particular, it affected their awareness of the position of the airplane relative to critical fixes and navaids necessary for the approach. Sinee the initial certification of the FMS on the B-757/-767, the Boeing Company has developed and implemented a change to the B-757 software that allowed such fixes to be retained in the display. However, this retrofit, part of a product improvement package for the airplane, had not been incorporated into the accident airplane. Aeronautica Civil believes that the FAA should evaluate all FMS-equipped aircraft and, where necessary, require manufacturers to modify the FMS logic to retain those fixes between the airplane's position and those the airplane is proceeding towards, following the execution of a command to the FMS to proceed direct to a fix.
Deficient situation awareness is also evident from the captain's interaction with the Cali air traffic controller. At 2137:29, the captain asked the controller if AA965 could "go direct to [the non directional beacon] Rozo and then do the Rozo arrival." The controller later stated that this question that made little sense since Rozo was a beacon located just before the approach end of runway, and not an initial or intermediate approach fix located considerably before the runway. The interaction with the controller continued at 2140:01, when the captain asked the controller a similar question. The captain announced his position and properly interpreted the approach when he asked "...You want us to go to Tulua and then do the Rozo ... to the runway?" While this question demonstrated that the captain understood the appropriate flight path necessary to execute the approach, his position report contradicted his statement, because the airplane had already crossed ULQ and therefore would have to reverse course to comply with his statement
In addition to deficiencies in situation awareness already noted, there is no evidence that, before the onset of the ground proximity warning system (GPWS) alert, the flightcrew recognized the proximity of terrain to the airplane's present and future flight path. The evidence suggests several explanations for this deficiency in the flightcrew's situational awareness:
There was evidence that AA provided the captain and first officer of AA965 with the information they needed to be sufficiently alert to the need to maintain constant awareness of proximity to terrain when operating in South America. The training and information that AA provided to its crews on the hazards specific to Latin America addressed many of the issues noted in the investigation of this accident. Following its entry into the South American market, AA developed the information in the reference guide and in training, after making significant effort to identify and address the unique demands of South American flight operations.
Aeronautica Civil believes that AA provided valuable information to its flightcrews regarding flying in South America, including many safety topics and advisories that were overlooked by the crew of AA965. Despite the high quality of the training that AA provided to their flightcrews, this accident demonstrates that the performance of flightcrews in the cockpit may not manifest the attitudes, skills, and procedures that such a training program addresses.
----------------
[26] AA defined airplanes deserving special pre approach briefing criteria.
Both the reference guide and the Latin American training program noted that three South American airports: Bogota, Colombia; Quito, Ecuador; and La Paz, Bolivia, were critical airports because of the effects of their high altitudes on aircraft performance. Pilots were required to meet additional training requirements before being permitted to fly into these cities for the first time. Because Cali, Colombia, was not at high altitude, it was not listed as a special airport and no additional training or checking was required to operate into it. Therefore, because it was not given "special consideration," the accident flightcrew may not have exercised the same level of vigilance when operating into Cali as they would have when operating into the three target airports.
In the years since the flightcrew members received their initial Latin American training, both had operated in South America and the captain had operated into Cali 13 times without incident. Over time, repeated exposure to flight operations into potentially hazardous environments can become routine as pilots acclimate to the environment and their vigilance is diminished. Unless information is presented regularly in a novel and interesting way, pilots may fail to display the lessons of earlier training when those lessons are most needed. The Investigation Team believes that the pilots of AA965 became task saturated and did not recognize that the hazards the airline had warned them about as they were encountered during the accident approach.
In addition, the first officer's lack of experience in the Cali environment served to increase his reliance on the captain for situational awareness. For example, at 2133:25, the first officer asked the captain for the transition level at which altimeter settings were to be changed on approach to Cali. Two minutes later, at 2135:44, he asked the captain whether speed restrictions were required, as well. Throughout the approach, the captain's experience into Cali appears to have reduced the first officer's otherwise assertive role as the pilot flying.
The CVR indicates that the flightcrew had insufficient time to review thoroughly or effectively the approach chart for Cali's VOR DME approach to runway 19. Had more time been available, the flightcrew likely would also have selected the VOR DME runway 19 approach in the FMS. By using the approach chart as the primary reference to execute the approach into Cali, the pilots relied on it as their source for terrain information. High point of the terrain were displayed by several altitude dots on the chart and their associated elevations above msl. Although this method presents the necessary information, it takes pilots time to recognize and understand its significance because of the lack of prominence of this
information. During a high workload period, or when insufficient time may be available to adequately review the chart pilots may not be able to assimilate that information to gain a comprehensive view of the airplane, its flight path, and its adherence to the approach parameters.
Before the accident, the Jeppesen Sanderson Company, the supplier of approach charts and navigation information for electronic navigation data bases, began to change the portrayal of terrain on the charts and maps that it supplied to its customers. In the new method, terrain is portrayed using graphics similar to those used in topographic charts, with colors added to enhance the prominence of terrain and heighten its contrast with other information on the chart. The criteria the company uses to determine whether to display terrain information on approach charts require that terrain is 2,000 feet above the airport within 6 miles of the airport, and on local area charts, that terrain is elevated more than 4,000 feet above the planned view of the airport. Because neither of these criteria was met in the VOR DME runway 19 approach chart, terrain was not graphically presented on it.
the terrain display criteria Jeppesen Sanderson developed were met regarding the local area chart, at the time of the accident the company had not yet converted the Cali local area chart to the new format. The chart that was available displayed terrain high points, but not in the same color graphic portrayal as is used in the newer format. Consequently, the chart used by the flightcrew did not graphically show the high terrain on either side of the descent into Cali. The Investigation Team believes that graphically portraying terrain information on approach charts is an effective means of presenting critical information to flightcrews quickly and without extensive interference with other tasks. Aeronautica Civil appreciates the efforts of Jeppesen Sanderson in upgrading its approach charts in order to present such information in an absence of a requirement to do so. Had this portrayal of terrain been available to the flightcrew, and had they referred to charts containing the information, it may have heightened their awareness of the proximity of terrain in their flightpath and the accident could have been avoided. Therefore, Aeronautica Civil believes that the FAA should require that all approach and navigation charts portray the presence of terrain located near airports, or flight paths.
The evidence from the flightcrew's statements on the CVR and their inability to initially locate ULQ indicates that they did not refer to the local area chart during the flight and only referred to the approach chart. Therefore, during the descent they had no information available that could have quickly informed them of
the proximity of terrain. AA did however, provide the flightcrew with written terrain information on the flightplan. This noted that: "Critical terrain exists durin