TUCSON, AZ, USA
N470AA
McDonnell Douglas MD-82
During takeoff/initial climb, the aircraft sustained a contained failure of the left engine turbine section, as well as a tail pipe fire. The flightcrew returned to the airport, made a successful landing, and stopped on the runway, where an evacuation was initiated. The flight deck crew gave the evacuation command and instructed the flight attendants to 'use the right side exits only.' A short time later, Flight 230 asked the tower 'how do I correspond with the folks in the trucks and make sure what's going on with the left engine . . .' The controller replied, 'you go to one two four point four that's the ground control frequency and airport forty six is in charge of the fire rescue.' Review of the transcripts revealed that the crew experienced difficulty in establishing radio contact with the airport CFR vehicles. Postincident engine teardown revealed considerable damage of the stage 1 to stage 4 turbine blades. The 1st stage NGV was found with the outer buttress aft flow guide (angel wing) completely missing. The 1T blade damage was consistent with damage caused by liberated angel wing hardware; however, determination of the initial fracture mode was not possible.
HISTORY OF FLIGHT On April 28, 1997, at 1222 hours mountain standard time, a McDonnell Douglas MD-82, N470AA, sustained a left engine turbine section contained failure and tail pipe fire during the takeoff initial climb from Tucson, Arizona. The aircraft returned to Tucson for a successful landing and stopped on the runway where a partial evacuation was accomplished. The aircraft was operated by American Airlines as Flight 230, a regularly scheduled domestic passenger flight from Tucson to Dallas-Fort Worth, Texas, under 14 CFR Part 121. Visual meteorological conditions prevailed and an IFR flight plan was filed. There were no injuries to the 118 passengers, 3 cabin attendants, and 2 flight crew. The aircraft sustained minor damage, which was confined to the engine and associated nacelle. While several houses under the aircraft's flight track sustained minor damage from falling hot engine parts, there were no ground injuries. Ground witnesses on the airport observed a puff of smoke emanate from the aircraft just after rotation. One passenger stated that he heard what he described as a "compressor stall" after liftoff. According to a preliminary statement from the captain, the aircraft was climbing through 1,800 feet agl when a loud bang was heard followed by the left engine spooling down. The engine was secured and one fire extinguisher bottle was fired. The crew returned for an uneventful landing on runway 29R and stopped. CRASH FIRE AND RESCUE RESPONSE Airport Crash Fire Rescue vehicles followed the aircraft and extinguished a tail pipe fire in the left engine after the aircraft came to a stop. As the airport fire department was extinguishing the tail pipe fire, about 16 passengers exited the forward left door via the slide (the only one deployed), and passengers were also climbing onto the wing from the over wing exit hatches on both sides of the aircraft. The CFR personnel stopped the evacuation on the forward slide, prevented the passengers on the wing from jumping to the ground, and talked them into moving back inside the aircraft. The remainder of the passengers and crew were deplaned using portable stairs. An examination of the ATC Transcript, which recorded the conversation between Tucson Air Traffic Control Tower and American Airlines Flight 230, revealed that the flight crew had requested additional information from the control tower about the condition of the left engine. The control tower verified that they observed flames out of the left engine. The flight deck crew gave the evacuation command and instructed the flight attendants to "use the right side exits only." A short time later, Flight 230 asked the tower "how do I correspond with the folks in the trucks and make sure what's going on with the left engine . . ." The controller replied, "you go to one two four point four that's the ground control frequency and airport forty six is in charge of the fire rescue." Review of the transcripts revealed that the crew experienced difficulty in establishing radio contact with the airport CFR vehicles. The number one flight attendant was riding in the forward entry door flight attendant jump seat. In her written statement and during her interview, she said that she heard the evacuation command, but she could barely hear the Captain on the P.A. and did not hear the right side only portion. She stated that she assessed the condition of the left forward entry door and that she saw no fire or smoke. Additionally, she said she saw fire trucks and firemen right outside the door. She said that one fireman "gave me the thumbs up, then I proceeded to open the door" and initiate an evacuation on the left side of the aircraft. One of the first fireman to arrive was from one of the Arizona National Guard units and was interviewed. He stated that the flight attendant had already initiated the evacuation process when he arrived on the scene. He said he gave the "thumbs up" hand signal to stop the evacuation and also attempted to verbally communicate with the flight attendant in order to stop the evacuation. After some difficulty, he succeeded in getting her to stop the evacuation. PERSONNEL INFORMATION The number one flight attendant was hired by American Airlines on December 13, 1990, after receiving her initial training on the MD-82 on December 12, 1990 (American Airlines does not formally offer a prospective flight attendant a job until they have successfully completed the initial flight attendant indoctrination). Her most recent recurrent training in this aircraft type was conducted on November 21, 1996. ENGINE TEARDOWN The engine, a Prattt & Whitney JT-8D, serial number 709843, had undergone a B-check on March 17, 1997. The postincident engine teardown was performed at the American Airlines Tulsa facility on May 30, 1997, under the supervision of the DFW Certificate Management Office of the FAA. The examination revealed that their was considerable damage and failure to stages 1-4 turbine blades. The examining engineers stated that "the 1st stage NGV was found with the outer buttress aft flow guide (angel wing) completely missing." According to the report, a determination of the fracture mode was not possible. A complete summary report of the teardown report is appended. ADDITIONAL INFORMATION Discussions with American's safety department disclosed that the company has been concerned in general for some time about the inability of flight crew's during an emergency to contact CFR units directly. Currently, American is contacting airports they serve and associated CFR units in an attempt to implement a known discrete frequency for their flight crews to communicate with emergency response units. The current chairman of the Air Transport Association (ATA) Flight Incidence Review and Analysis committee stated that "it is the consensus of the ATA members that the dedicated frequency [for flight crews to talk to responding CFR units] is an appropriate tool."
an undetermined failure in the #1 (left) engine turbine assembly, which resulted in a fracture of the first stage nozzle guide vane (NGV) and subsequent damage to the turbine blades.
Source: NTSB Aviation Accident Database
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