# NTSB FTW94IA321: Mcdonnell Douglas MD-11-F, N603FE, Anchorage, AK, September 29, 1994 - Type: NTSB incident investigation - Classification: Incident · No injuries · Incident investigation · Final report - Date: September 28, 1994, 20:50 local (Sep 29, 1994, 00:50 UTC) - Place: Anchorage, AK - Coordinates: 61.159744, -149.989593 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=61.1597&lon=-149.9896&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report May 4, 1995 - Report: Approved by Office Director - NTSB case key (mKey): 18943 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW94IA321 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/18943/pdf - Page: https://openairdocs.org/ntsb/FTW94IA321 ## Probable cause RIGHT INBOARD FLAP VANE COMPONENT SEPARATION DUE TO UNDETERMINED REASONS. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, approach - flight control,flap - separation (cause) - flight control,flap attachment - sheared (cause) - reason for occurrence undetermined (cause) ## Analysis THE RIGHT HAND INBOARD FLAP VANE DEPARTED THE AIRFRAME WHEN THE AIRPLANE WAS 500 FEET ABOVE THE GROUND ON FINAL APPROACH TO THE RUNWAY. THE VANE TO TRACK SUPPORT, AFT ADJUSTMENT ECCENTRIC, AND THE SPRING CARTRIDGE STOP ASSEMBLY SEPARATED DUE TO TENSILE OVERLOAD; HOWEVER, THE TENSILE PROPERTIES DID NOT APPEAR TO INFLUENCE THE FAILURE OF THE VANE. THE SUPPORT TRACK, THE ROLLER SUPPORT BOLT, AND THE FLAP SUPPORT BUSHING SEPARATED DUE TO SHEAR OVERLOAD. TESTING FAILED TO DETERMINE THE CAUSE FOR THE FAILURE. ## Factual narrative On September 28, 1994, at 2050 Alaska standard time, a McDonnell Douglas MD-11-F, N603FE, received minor damage during approach near Anchorage, Alaska. The crew of two were not injured. Visual meteorological conditions prevailed for Federal Express Flight 81, scheduled Title 14 CFR Part 121 cargo flight to Anchorage, Alaska. Company personnel and Federal Aviation Administration inspectors reported that the right hand inboard wing flap vane departed the airframe when the airplane was 500 feet above the ground on final approach. The airplane landed without further incident and taxied to the gate. The Federal Aviation Administration (FAA) inspector and the airplane manufacturer examined the components and found the right inboard flap vane components: #2 vane to track support (P/N ARC7481-1), aft adjustment eccentric (P/N 2941-503), and the spring cartridge stop assembly (P/N ARC2948- 2), separated due to tensile overload. The tensile properties "did not appear to influence the failure of the vane" (enclosed report). The support track (P/N ARC2700-501), the roller support bolt (P/N ARC3154-1), and the flap support bushing (P/N ARC7495-1) separated due to shear overload. During flight testing the flap system was instrumented using strain gauges. During the testing the manufacturer isolated vibratory loads that were being imparted in a lateral motion on the failed part. They reported that no fatigue was evidenced in the failed parts. Additional testing concluded that part of the assembly (part numbers ARC7481-1 and ARC2941-503) were not manufactured in accordance with the current engineering drawings. A review of these components by the manufacturer's Material Review Board subsequently declared them within the safety requirements. It was also determined that these components, although non-conforming, did not contribute to the failure of the system. ## Aircraft - Registration: [N603FE](https://openairdocs.org/aircraft/N603FE), registered now, S/N 48459, built 1991 (OpenAirDocs) - Reported make and model: MCDONNELL DOUGLAS MD-11-F - Registry model: [Mcdonnell Douglas MD-11F](https://openairdocs.org/model/mcdonnell-douglas-md-11f) (registry code 3023600) (OpenAirDocs) - Registry engine: [GE CF6-80 series](https://openairdocs.org/engine/ge-cf6-80-series) (registry code 30025, turbo-fan) (OpenAirDocs) - Category: Airplane - Serial number: 48459 - Airframe hours: 9642 - Engines: GE CF-6-80C2D1F 6067 lbs thrust turbo fan - Damage: Minor damage - Flight: Part 121 - Operator: Federal Express - Registered owner: Wilmington Trust Co., Trustee - Airworthiness certificate: Special, Experimental (Special); Standard, Transport; Standard, Normal - Departed: EWR, NEWARK, NJ - Destination: ANC, AK - Flight plan: IFR - Airport: ANC, Anchorage International, runway 6R, 10,897 × 150 ft, concrete ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 38; airline transport, foreign, student; airplane ratings: multi-engine land, single-engine sea; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 7,351 total, 503 in this make and model, 3,425 as pilot in command, 142 in the last 90 days, 52 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 20° at 7 knots - Visibility: 60 statute miles - Lowest ceiling: none - Temperature: 55 °F, dew point 37 °F - Altimeter: 30.00 inHg From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.