Phoenix, AZ, USA
N635AW
Airbus Industrie A320-231
After an asymmetrical deployment of the thrust reversers during landing rollout deceleration, the captain failed to maintain directional control of the airplane and it veered off the runway, collapsing the nose gear and damaging the forward fuselage. Several days before the flight the #1 thrust reverser had been rendered inoperative and mechanically locked in the stowed position by maintenance personnel. In accordance with approved minimum equipment list (MEL) procedures, the airplane was allowed to continue in service with a conspicuous placard noting the inoperative status of the #1 reverser placed next to the engine's thrust lever. When this crew picked up the airplane at the departure airport, the inbound crew briefed the captain on the status of the #1 thrust reverser. The captain was the flying pilot for this leg of the flight and the airplane touched down on the centerline of the runway about 1,200 feet beyond its threshold. The captain moved both thrust levers into the reverse position and the airplane began yawing right. In an effort at maintaining directional control, the captain then moved the #1 thrust lever out of reverse and inadvertently moved it to the Take-Off/Go-Around (TOGA) position, while leaving the #2 thrust lever in the full reverse position. The thrust asymmetry created by the left engine at TOGA power with the right engine in full reverse greatly increased the right yaw forces, and they were not adequately compensated for by the crew's application of rudder and brake inputs. Upon veering off the side of the runway onto the dirt infield, the nose gear strut collapsed. The airplane slid to a stop in a nose down pitch attitude, about 7,650 feet from the threshold. There was no fire. Company procedures required the flying pilot (the captain) to give an approach and landing briefing to the nonflying pilot (first officer). The captain did not brief the first officer regarding the thrust reverser's MEL'd status, nor was he specifically required to do so by the company operations manual. Also, the first officer did not remind the captain of its status, nor was there a specific requirement to do so. The operations manual did state that the approach briefing should include, among other things, "the landing flap setting...target airspeed...autobrake level (if desired) consistent with runway length, desired stopping distance, and any special problems." The airline's crew resource management procedures tasked the nonflying pilot to be supportive of the flying pilot and backup his performance if pertinent items were omitted from the approach briefing. The maintenance, repair history, and functionality of various components associated with the airplane's directional control systems were evaluated, including the brake system, the nose landing gear strut and wheels, the brakes, the antiskid system, the thrust levers and reversers, and the throttle control unit. No discrepancies were found regarding these components.
1.1 HISTORY OF FLIGHT On August 28, 2002, at 1844 mountain standard time, an Airbus Industrie A320-231, N635AW, operating as America West Airlines flight number 794, landed on runway 08 at the Phoenix Sky Harbor International Airport, Phoenix, Arizona. While decelerating about midfield, the airplane veered right and exited off the side of the runway. Thereafter, the airplane crossed the apron area east of intersection B8 and experienced the separation of its nose gear strut assembly upon traversing the dirt infield area south of the runway, where it slid to a stop on its nose. The airplane was substantially damaged. On board the airplane there were 2 flight crewmembers, 3 flight attendants, and 154 passengers (including 4 lap children), for a total of 159 occupants. Of the 10 persons injured, 1 of the crewmembers (the captain) sustained a minor injury, 7 passengers and 1 lap child sustained minor injuries, and 1 passenger was seriously injured. The daytime flight was performed under the provisions of 14 CFR Part 121. Visual meteorological conditions prevailed. The 2 hour 41 minute flight departed from Houston, Texas, at 1803 central daylight time. Days earlier, the airplane's #1 thrust reverser had been rendered inoperative (MEL'd). The #1 thrust reverser system had been mechanically locked out by maintenance personnel thereby precluding its usage. The captain of the accident airplane reported to National Transportation Safety Board investigators he had been informed by the captain of the preceding flight, following its arrival in Houston, that the #1 thrust reverser was inoperative and had been MEL'd. At 1840, while approaching Phoenix during the accident flight, a Federal Aviation Administration (FAA) air traffic local controller issued the airplane (call sign Cactus 794) a clearance to land on runway 08. The crew acknowledged the clearance and continued their straight-in visual approach to the runway. FAA recorded radar data indicates that the airplane descended at an approximate 3-degree descent angle from at least 7 miles west of the airport until arriving in the vicinity of the runway threshold. The airplane's captain indicated to the Safety Board's Operations Group Chairman that he was the pilot flying (handling the flight controls). The captain indicated that the airplane's touchdown and his derotation on the runway's centerline was normal. The touchdown occurred about 1,200 feet beyond the threshold, and he initially maintained directional control of the airplane. At 1843:40, the air traffic controller stated to the crew of Cactus 794, "I appreciate the first right turn you can make then a left turn on Bravo and contact ground." In the captain's written statement he reported, in part, that after retarding both thrust levers to the idle position, he engaged the #2 (right side) thrust reverser. Shortly thereafter, the airplane started slowly diverging to the right. The captain reported that he reached down to ensure that the #1 (left side) thrust lever was in idle, and he reduced thrust on #2 while feeding in left rudder steering. The airplane did not respond to the steering input, so he added more pressure to the left brake, which did not correct the airplane's course. The airplane exited off the right side of the runway, and the nose wheel dropped into a ditch. (See the "Airplane Information" section of this report and the "Safety Board Operations Group Chairman's Factual Report" for a description of thrust reverser operation and procedures.) The air traffic controller observed the airplane veer off the runway and traverse the infield. The controller stated to the flight crew, at 1844:35, "there doesn't appear to be any fire coming out of your wings." At 1845:00, the controller said, "ah theres we see no fire or smoke coming out the vehicles are on their way out right now." The crew responded and stated, at 1845:04, "we're going to evacuate the aircraft." 1.2 INJURIES TO PERSONS Fire department personnel reported having evaluated 150 occupants. Five of the occupants were transported to medical facilities; the others were treated locally, as needed. The injuries generally consisted of head, neck, shoulder, and back trauma. 1.3 DAMAGE TO AIRPLANE In pertinent part, the external examination of the airplane revealed lateral skin panel buckling on the sides of the airplane from the aft nosecone area near frame #1, through frame #12, located about 9.5 feet aft. The bottom surface of the airplane's nose was crushed upward a maximum of 12 inches. Regarding interior structure in the vicinity of the nose gear wheel well, the forward pressure bulkhead was found bent and cracked. The rear pressure bulkhead was bent. 1.4 PERSONNEL INFORMATION, FLIGHT CREW The accident occurred on the second day of the flight crew's scheduled 3-day flight sequence, which began on August 27 with a flight from Phoenix, Arizona, to San Diego, California, to Phoenix, and then to Houston, Texas. On August 28, the flight to Phoenix blocked out of the gate about 1744 central daylight time. 1.4.1 The Captain. The captain, age 59, held an airline transport pilot certificate, with an airplane single and multiengine land and rotorcraft helicopter ratings. He held type ratings in the Airbus A320 and the DHC-8. He possessed a first-class aviation medical certificate with the limitation that he must have available glasses for near vision. A review of the captain's FAA records indicated that he had no history of prior accidents, incidents, or enforcement actions. The captain's total flight time was reported at 19,500 hours, of which 7,000 hours were as captain flying an A320. During the preceding 24 hours, 30, and 90 days the captain had flown for 4, 76, and 232 hours, respectively. The captain's last A320 proficiency check was accomplished in July 2002. The captain reported that following his arrival in Houston on August 27, he had a 15-hour layover. He stated that he had sufficient sleep in Houston. On August 28, he had lunch with his first officer prior to reporting for duty. 1.4.2 The First Officer. The first officer, age 40, held an airline transport pilot certificate, with airplane single and multiengine land ratings. He held type ratings in the B-737, BA3100, and SF-340. He possessed a first-class aviation medical certificate with the limitation that he must wear corrective lenses. A review of the first officer's FAA records indicated that he had no history of prior accidents, incidents, or enforcement actions. His total flight time was reported at over 11,000 hours, of which 800 hours were acquired flying an A320. During the preceding 24 hours, 30, and 90 days the first officer had flown for 4, 53, and 173 hours, respectively. The first officer's last A320 proficiency check was accomplished in February 2002. The first officer reported that following his arrival in Houston on August 27, he likewise had a 15-hour layover. He stated that he had sufficient sleep in Houston. He stated that his rest the night before was adequate, sleep was sufficient and normal, and his fatigue level was insignificant. 1.5 AIRCRAFT INFORMATION 1.5.1 Maintenance, General. The airplane, serial number 092, was manufactured in 1990. America West Airlines maintained the airplane on a continuous airworthiness basis following the Airbus maintenance inspection program. The program was reviewed for accomplishment of the prescribed Through-Flight Checks, 4- and 8-Day Checks, A & C Checks, and for compliance with airworthiness directives. According to the FAA participant, the program audit revealed that America West Airlines had followed the approved maintenance program. The last "C" check and "A" checks were accomplished as scheduled on September 27, 2001, and on July 22, 2002, respectively. By the accident date, the airplane had 40,084 total hours and 18,530 cycles. 1.5.2 Landing Gear. The airplane's nose and main landing gear overhaul records indicated that all three gears were last overhauled in October 1999. All three gears were installed on the accident airplane in November 1999. All three gears have 18,262 cycles since new and 3,863 cycles since the last overhaul. No sub-components of the nose landing gear assembly have been replaced since installation. 1.5.3 Thrust Reverser Operation and Service History. The "Landing" section of the America West Airlines "Flight Crew Operations Manual" (FCOM) states the following: "After main gear touchdown, immediately raise the reverse thrust levers to the full reverse position and adjust reverse thrust as necessary. The "Powerplant Controls and Indicators" section of the FCOM provides a description of the airplane's reverser latching levers and thrust levers. In part, the manual indicates that a thrust lever is placed into the reverse position by first pulling up the reverser latching lever that is located on the front of the thrust lever. Thereafter, the thrust lever may be retarded in an aft direction thereby placing it into the reverse thrust position. (See the Safety Board Operations Group Chairman's Factual Report, Attachment 9, for drawings and additional information.) The thrust reverser systems for the two engines function independently of each other. Pursuant to America West Airlines procedures, N635AW could be dispatched with an inoperative (MEL'd) thrust reverser. On August 17, 2002, the #1 thrust reverser failed to deploy on landing in Phoenix. The system was repaired, operationally checked, and was found serviceable. Later on August 17, the #1 thrust reverser failed to deploy again. Maintenance personnel deactivated the reverser and deferred maintenance pursuant to MEL 78-30-01. On August 18, the #1 thrust reverser underwent maintenance. It was satisfactorily operationally checked, and the MEL placard was removed. On August 20, the #1 thrust reverser did not deploy. It was deactivated, and its status was placarded pursuant to the aforementioned MEL. The airplane's operation continued with the MEL'd thrust reverser. On August 27, repair parts were ordered; however, they had not been installed by the time that the flight crew was dispatched on August 28. At dispatch, the #1 thrust reverser continued to be listed as inoperative pursuant to the MEL. The MEL placard was required to be affixed to the throttle quadrant. Following the accident the quadrant area was photographed, and the placard was noted (see photograph). 1.5.4 Flight Operation Procedures, Thrust Reverser, and Callouts. According to the MEL, when a thrust reverser is deactivated "it is recommended not to select reverse thrust on affected engine at landing." The airline's procedures, as indicated by information in its simulator lesson guide for thrust reverser operation and related airspeed callouts (pursuant to the FCOM), is as follows: "Reverse thrust is most effective at high speeds and will always reduce the 'brake only' stopping distance. Reverse thrust is effective down to as low as 60 knots." "After main gear touchdown and with the thrust levers at idle, immediately raise the reverse thrust levers to the full reverse position. The FADEC [Full Authority Digital Engine Control] limits N1 during MAX REVERSE." "Although the FADEC will control the maximum thrust, the PNF should monitor engine operating limits, and call out any engine operational limits being approached, exceeded or any other abnormalities." "Maintain up to the maximum reverse thrust until the airspeed decreases to 80 knots. At 80 knots, the PNF announces '80 KNOTS.'" "After 80 knots, start reducing reverse thrust toward idle reverse to be at idle reverse by 60 knots. At 60 knots, the PNF announces '60 KNOTS.'" 1.5.5 Approach and Landing Briefings. America West Airlines had procedures in effect for the conduct of approach and landing briefings. In pertinent part, the airline's policy indicated that the pilot flying (PF) should initiate the approach and landing briefing. The FCOM specified "the pilot flying will make any callout the non-flying pilot does not make." The airline had guidelines for the role of the pilot not flying (PNF) during the time when the PF briefs the approach. In pertinent part, the crew resource management approach encouraged the PNF to be supportive of the PF, and backup his conduct/performance if he omitted items pertinent to the approach briefing. The FCOM stated that "All approaches have certain basics in common. These are good descent planning, careful review of the approach procedures, accurate flying and good crew coordination." In part, in the FCOM's "Approach Briefing and Planning" section, it stated the following: "The PNF will obtain the airport information as soon as possible and inform the PF of the landing runway currently in use. The PF will brief these items as soon as specific airport conditions are known prior to top of descent: ...The landing flap setting, ...target airspeed...autobrake level (if desired) consistent with runway length, desired stopping distance, and any special problems." (The FCOM was changed following the accident. The following specific briefing item was added: "Crews must also brief any en route failure or MELs that may affect the landing and rollout.") 1.6 METEOROLOGICAL INFORMATION At 1840:11, the local Phoenix Sky Harbor Airport controller reported to Cactus 794 that the wind direction was from 060 degrees, and its speed was 12 knots. About 1843, the wind speed had increased to 16 knots. At 1856, the Phoenix Airport weather was, in part, wind from 090 degrees at 14 knots, with 10 miles visibility. On the accident day in Phoenix, sunset occurred at 1859. The end of civil twilight was at 1924. The ambient light condition inside and outside the airplane was evaluated on September 5. On this date sunset occurred at 1848, about 11 minutes earlier than on the day of the accident. The end of civil twilight occurred at 1914. The America West Airlines Operations Safety Director and the Cabin Safety Manager reported that during their September 5 inspection, which was performed about the time of the accident, there was sufficient light to clearly see. 1.7 AIRPORT AND GROUND FACILITIES Runway 08 is oriented on a magnetic bearing of 078 degrees. In the vicinity of the runway threshold, the elevation is 1,109 feet mean sea level. The runway is 11,490 feet long and 150 feet wide. The runway has a concrete grooved surface, and it was dry at the time of the accident. Design engineering terrain elevation and slope data was received from airport administration personnel. A comparison was made between the provided data and the Safety Board investigation team's observations of the actual terrain. No discrepancies were noted. The terrain has its maximum elevation at the runway crown, and it gradually slopes downward toward the runway edge. Thereafter, the terrain elevation continues to decrease on the taxiway apron and reaches its lowest point in the infield area where the airplane came to rest. No drainage culverts or berms existed along the accident airplane's rollout path. 1.8 FLIGHT RECORDERS The cockpit voice and digital flight data recorders were examined by the Safety Board's Vehicle Recorder Laboratory in Washington, D. C. 1.8.1 Cockpit Voice Recorder. The airplane was equipped with a Fairchild Model A-100A cockpit voice recorder (CVR), serial number 26340, which showed no evidence of structural damage. The interior of the recorder and the tape sustained no apparent heat or impact damage. A Dukane underwater locator beacon (ULB) was installed on the recorder. It was found to be inoperative when tested in the Safety Board's laboratory. A transcript was prepared of the cockpit communications during the latter portion of the flight and accident sequence. The transcript starts at 1813:40 mountain standard time and ends at 1824:58. Thereafter, about 13 minutes of nonpertinent conversation between the pilots was not transcribed. The transcript resumes at 1838:15, as the flight was vectored for landing on runway 08. The transcript covers the captain (pilot flyin
The captain's failure to maintain directional control and his inadvertent application of asymmetrical engine thrust while attempting to move the #1 thrust lever out of reverse. A factor in the accident was the crew's inadequate coordination and crew resource management.
Source: NTSB Aviation Accident Database
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