FORT LAUDERDALE, FL, USA
CFRYS
Boeing 727-212
On takeoff roll, between 90 and 100 knots, the No. 2 engine sustained an uncontained failure. The flight crew aborted the takeoff and when informed that smoke was emanating from No. 2 engine, the crew brought the airplane to a stop on a taxiway, and the pilot commanded a passenger emergency evacuation. Examination of the engine revealed that one of 12 low pressure compressor (LPC) rear tiebolts fractured at its 4th stage disk land and was separated into the plenum ahead of the LPC. The separated tierod impacted the other 11 tierods until they eventually fractured, causing catastrophic separation of the LPC assembly between the 3rd and 4th stage rotors. Metallurgical examination of the failed tierods revealed the first tierod failed due to fatigue and the other 11 due to stress. It was further revealed that an anti-gallant treatment to the tierods that are used to bolt the 3rd through 6th compressor disks together as a unit was not present. The treatment is applied to the lands of the tierods at manufacture as specified in Pratt & Whitney Service Bulletin No. 5407.
HISTORY OF FLIGHT On March 30, 1998, about 2114 eastern standard time, a Boeing 727-212, Canadian registration C-FRYS, registered to and operated by Royal Aviation, Inc., as flight 311, a Title 14 CFR Part 129, nonscheduled international passenger flight, from Fort Lauderdale, Florida to Toronto, Canada, experienced a failure of No. 2 engine during takeoff roll at Fort Lauderdale-Hollywood International Airport. Visual meteorological conditions prevailed and an instrument flight plan was filed. The airline transport-rated pilot, first officer, flight engineer, 5 flight attendants, and 169 passengers, including 2 lap children, were not injured. Three passengers sustained serious injuries and 14 passengers sustained minor injuries during the emergency evacuation after takeoff was aborted. The flight was originating at the time of the accident. The pilot stated that during takeoff roll from runway 9L, between 90 and 100 knots indicated airspeed, he felt a "thud" and observed an "engine fail" light and No. 2 engine fire warning . At about 110 knots, he aborted the takeoff, brought the airplane to a stop on a high-speed taxiway, and requested that the "engine fire on ground" and "aborted takeoff" check-lists be read and accomplished. When the tower advised that smoke was still emanating from the engine tailpipe, the pilot commanded that a passenger emergency evacuation be accomplished, and that the "emergency evacuation" checklist be read and accomplished. The four fuselage doors and slides were used, as well as the four overwing exits. The aft airstairs were not used. The pilot further stated that the flight attendant's safety brief, including emergency evacuation exits and escape routes had been given to the passengers, according to company procedures. The evacuation took about 3 minutes. Fire rescue personnel stated that upon arrival at the aircraft they observed that some passengers had assembled on-wing at the wing-tips. They were directed back toward the wing root area by the first officer and fire rescue personnel on the ground, and that no one actually jumped from the wing tip area. PERSONNEL INFORMATION Information on the pilot, first officer, and flight engineer is included in this report under First Pilot, in supplement E, and in the attached Pilot/Operator Aircraft Accident Report. AIRCRAFT INFORMATION The aircraft, a Boeing 727-212, had been modified in accordance with Federal Aviation Administration Supplement Type Certificate SA 5938 NM. As part of the modification, the wing-tips had been modified to the winglet type. The trailing edge flaps were limited to 30 degrees from the original 40 degrees, by a blocking device installed on the cockpit flap quadrant. Examination of the aircraft after the accident showed the ground evacuation emergency checklist mounted on the cockpit yoke, and the Royal Airlines printed cockpit checklist called for "FLAPS-40", which was not possible. Examination of the aircraft also showed the passenger seatback pockets contained the Royal Airlines, Boeing 727-200 Safety Card, that depicts the escape route from each emergency escape exit. For additional information, see attached flight manual supplement for Boeing 727-200 series with STC SA 5938 installed under, Other Pertinent Forms and Reports. A copy of the seatback safety card is attached under, Other Pertinent Forms and Reports. METEOROLOGICAL INFORMATION Visual meteorological conditions prevailed at the time of the accident. For additional information, see Weather Information included in this report. FLIGHT RECORDERS The digital flight data recorder was removed from the airplane on April 1, 1998, and sent to the NTSB Vehicle Recorders Laboratory, Washington, D.C. The data extracted confirms the airplane's positioning to runway heading, the 3-engine spool-up to about 1.6 EPR, (engine pressure ratio, the primary thrust setting instrument) for 3 seconds, and the continuous increase of thrust to takeoff EPR of 2.1. The number 2 engine EPR sharply decreases to about 1.0 at an airspeed of 105 knots, followed immediately by the sharp decrease and slight increase of EPR's 1 and 3. (For additional information see the Flight Data Recorder/Specialist's Factual Report of Investigation.) WRECKAGE AND IMPACT INFORMATION Postaccident inspection of the aircraft was conducted by NTSB and FAA personnel on April 1, 1998. The No.2 engine failure was uncontained just aft of the low pressure turbine, (LPT). The engine was cut completely in half just aft of the LPT. The fan exhaust duct was completely severed and the LPT case was completely separated from the remainder of the turbine exhaust case. The LPT containment shield was broken into several pieces. The LPT disks were intact but the blades were all fractured just above their root platforms, and most of them had been liberated. The two fan rotors and the 3rd stage compressor rotor could be rotated as a unit, but rotated independently of the remainder of the low pressure rotor assembly. The aft cowling halves had fire blistered paint and numerous shrapnel perforations just aft of the LPT's plane of rotation. Airframe and engine damage is included on page 3 and page 5 of the attached Powerplants Group Chairman's Factual Report. Teardown inspection of the No. 2 engine by the Powerplants Group showed initial engine component failure was one or more of the 12 low pressure compressor, (LPC) rear tierods. One tierod had failed at its 4th stage compressor disk land and the 11 others failed adjacent to their threaded ends. (For additional information see the Powerplants Group Chairman's Factual Report.) MEDICAL INFORMATION A report from on-scene EMS personnel indicated that 17 passengers were treated at the scene and transported to three area medical centers for further evaluation. Injuries to those passengers included one small arm laceration, one hip trauma, one hypertensive reaction, and 11 with ankle trauma. The serious injuries were three fractured ankles sustained while sliding off the wing flap trailing edge to the ground. TESTS AND RESEARCH The 12 LPC rear tierods, (PN 789550) and pieces of the failed low pressure turbine (LPT) containment shield were removed and shipped to the NTSB Materials Laboratory, Washington, D. C. It was revealed that an anti-gallant treatment to the tierods that are used to bolt the 3rd through 6th compressor disks together as a unit was not present. The treatment is applied to the lands of the tierods at manufacture as specified in Pratt & Whitney Service Bulletin No. 5407. One tierod was fractured transversely across the tierod's 4th stage compressor disk land. The entire fracture face on the tierod had surface corrosion, suggesting that the tierod had been broken for some time. The 11 remaining LPC rear tierods were fractured at their forward ends between the 3rd stage compressor disk lands and the tierod nut threads. These 11 fractures appeared to be overload caused. Pockmarks and bending damage suggest that after initial tierod fracture and liberation of its tierod end/nut, it tumbled around in the cavity at the front of the LPC and impacted the other tierod ends/nuts until they eventually fractured, causing the catastrophic compressor separation. Eleven equally spaced fan exit vanes showed imprints of the tierod ends/nuts on their leading edges, indicating that the 11 remaining tierods fractured nearly simultaneously at engine failure. For additional information see attached, NTSB Poweplants Group Chairman Factual Report and NTSB Materials Laboratory Factual Report. Regarding the discrepancy between printed checklist response of "Flaps 40" for an emergency evacuation flap setting and having the maximum flap setting physically blocked at "Flaps 30", Royal Airlines flight operations personnel stated that the checklists simply had not been updated. Because of the flap extension limitation, the difference between 30 degrees and 40 degrees was measured. Standing on the wing's trailing edge, the difference to an evacuating passenger is visually imperceptible due to the fact that after 30 degrees, additional flap movement is straight down, relative to the aircraft's longitudinal axis. Measured from the ground to the trailing edge of the flap, at 40 degrees, inboard flap is 27 inches, inboard end, to 33 inches, outboard end. At 30 degrees, inboard flap is 42 inches, inboard end, to 47 inches, outboard end. The Boeing Aircraft Company stated that the airplane was designed to the FAA requirements for overwing egress. Design considerations when authorizing flaps 30 as a maximum is within compliance with FAR Part 25.810 which requires that only heights of greater than six feet, (from passenger standing surface to ground level) require additional egress assistance be provided. The Boeing statement is located under, Reports from Parties to the Investigation. The Royal Airlines Flight Attendant Manual's recommended pre-departure safety announcement states the number of exits, their locations, how to identify them, and which ones are equipped with inflatable slides. The announcement makes no mention of the escape path direction once the evacuee steps through the overwing exit and out onto the wing. Excerpts from the manual are located under, Other Pertinent Forms and Reports. ADDITIONAL INFORMATION The aircraft was released by NTSB to the airline's contract ground handler at about 2309 on March 31, 1998. The deployed emergency evacuation slides were removed and the aircraft was towed to a terminal gate for passenger personal effects retrieval. The aircraft was subsequently towed to a hangar ramp area where investigators examined the airplane the next morning. Except for the engine LPC rear tierods and the LPT containment shield pieces, the engine was released to Royal Airlines at the completion of the teardown inspection on April 8, 1998. The tierods were returned to Royal Airlines on August 12, 1998. The pieces of the LPT containment shield were discarded per authorization from Royal Airlines on August 12, 1998. The FDR and CVR were returned to Royal Airlines on December 9, 1998. Additional parties to the NTSB investigation not listed in the factual portion of the report were Dennis Campbell, Transport, Canada, and Pamela Rosnik, Boeing Aircraft Co.
Failure of the No.2 engine low pressure compressor rear tierod. Also contributing to the accident was failure of the manufacturer to apply an antigallant treatment to the tierod's compressor disk lands during manufacture.
Source: NTSB Aviation Accident Database
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