# NTSB FTW02FA003: Fokker F28 Mk 0100, N1448A, DFW Airport, TX, October 3, 2001 - Type: NTSB accident investigation - Classification: Accident · No injuries · Field investigation · Final report - Date: October 3, 2001, 08:36 local (13:36 UTC) - Place: DFW Airport, TX - Coordinates: 32.891109, -97.035835 - Nearby events: https://openairdocs.org/map.md?lat=32.8911&lon=-97.0358&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 86 uninjured - Status: Completed, report August 26, 2003 - Report: Approved by Office Director - Parties: Federal Aviation Administartion, American Airlines Inc., Messier Services, Inc., Stork (Fokker Services) - NTSB case key (mKey): 53565 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW02FA003 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/53565/pdf - Page: https://openairdocs.org/ntsb/FTW02FA003 ## Probable cause The collapse of the nose landing gear as a result of the failure of company maintenance personnel to follow the proper procedures for a towing the airplane with an unsafe nose landing gear indication. Contributing factors were the inadequate communication between the company maintenance personnel, the inaccurate instructions provided to the maintenance crew, and the failure of the nose landing gear's locking mechanism. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, approach - landing gear,nose gear assembly - inoperative (contributing factor) - landing gear,gear locking mechanism - failure (contributing factor) - Gear collapsed, taxi - pushback/tow - procedures/directives - not followed, company maintenance personnel (cause) - landing gear,nose gear - communications - inadequate, company maintenance personnel (contributing factor) - instructions,written/verbal - inaccurate, company maintenance personnel (contributing factor) ## Analysis While on final approach to the runway the captain received an unsafe nose landing gear indication on the multi function display unit (MFDU) in the cockpit. The captain abandoned the approach and "recycled the gear per procedures to no avail." Subsequently, the airplane landed on runway 13R, rolled out, and came to a stop on the runway. An evacuation of the airplane was not initiated. A maintenance crew met the airplane on the runway and placed locking pins in the gear. Multiple simultaneous communications/conversations ensued between the maintenance crew, a maintenance supervisor, a maintenance crew chief and the flight crew. During the communications, the flight crew questioned maintenance personnel on whether or not it was necessary to strap the gear, the supervisor searched the maintenance manuals and didn't find any reference to strapping the gear, and informed the maintenance crew that it was not necessary to strap the gear prior to towing. Review of the maintenance manual found numerous warnings regarding towing the airplane with an unsafe nose landing gear indication. Meanwhile, a maintenance crew chief was informing the maintenance personnel that strapping of the gear was required; however, there was no strap at the airport. Despite a placard, located on the nose landing gear door, the maintenance crew attempted to tow the airplane without strapping the nose landing gear. Subsequently, the nose landing gear collapsed and the nose of the airplane came to rest on the towbar. The passengers were then deplaned and transported to the terminal by a bus. Examination of the nose landing gear did not reveal the reason for the down-lock plunger to engage when the nose landing gear was extended. ## Factual narrative HISTORY OF FLIGHT On October 3, 2001, at 0836 central daylight time, a Fokker F28 Mk 0100 (F-100) airplane, N1448A, operating as American Airline's (AA) flight 535, was substantially damaged while being towed to the gate at the Dallas-Fort Worth International Airport (DFW), DFW Airport, Texas. The airplane was registered to and operated by American Airlines Inc., of Fort Worth, Texas. The captain, who held an airline transport pilot certificate, the first officer, who also held an airline transport pilot certificate, two cabin attendants, and 82 passengers were not injured. Visual meteorological conditions prevailed, and an instrument flight rules flight plan was filed for the 14 Code of Federal Regulations Part 121 scheduled passenger flight. The flight originated from the Tulsa International Airport, Tulsa, Oklahoma, at 0712, and was destined for DFW. According to AA, the flight was the first flight following a light "C" maintenance check. According to the captain, while on final approach to runway 13R at DFW he received an unsafe nose landing gear indication on the multi function display unit (MFDU) in the cockpit. The captain abandoned the approach and "recycled the gear per procedures to no avail." Air Traffic Control (ATC) requested that another airplane, a King Air, check the condition of the F-100's nose landing gear. The King Air's flightcrew reported the landing gear appeared to be extended. Subsequently, the airplane landed on runway 13R, rolled out, and came to a stop on the runway. An evacuation of the airplane was not initiated. According to a AA maintenance personnel and the captain, a maintenance crew met the airplane on the runway, placed locking pins in each of the landing gears, connected the towbar, and prepared to tow the airplane to the gate. Prior to commencing the tow, the captain asked the maintenance crew for clarification regarding "strapping" of the nose landing gear prior to towing. A conversation between the maintenance crew at the airplane and the supervisor, who was located a separate location on the airport, via handheld radio ensued. The supervisor informed the maintenance crew he did not see anything regarding strapping of the nose gear in the maintenance manuals. Meanwhile, a maintenance crew chief, located at another location, contacted the captain and informed him that strapping of the nose gear prior to towing the airplane was required. The captain then contacted the supervisor again, and asked if the gear needed to be strapped. The supervisor responded that he was referencing the manuals and would respond in 2-3 minutes. Two minutes later, the supervisor informed the maintenance crew the gear did not need to be strapped. Subsequently, the captain released the airplane brakes, the maintenance crew placed the tug vehicle into low gear, and the nose landing gear collapsed. The nose of the airplane came to rest on the towbar. The maintenance crew reported the tug vehicle did not move forward; the gear collapsed when the brakes were released and the tug vehicle was placed into low gear. Following the maintenance supervisor's communication with the maintenance crew, he was contacted by the maintenance crew chief and was informed that strapping of the nose landing gear was required; however, the strap was not available at DFW. The passengers were deplaned and transported to the terminal by bus. The nose landing gear was removed from the airplane for further examination. PERSONNEL INFORMATION On January 5, 2000, the captain was issued an airline transport pilot certificate. He was type rated in the F-100 and had accumulated a total of 7,109.0 flight hours, of which 5,286.4 hours were in the F-100. On February 6, 2001, he underwent his most recent FAR Part 121 proficiency check. On August 11, 1997, the first officer was issued an airline transport pilot certificate. He was type rated in the F-100 and had accumulated a total of 413.27 flight hours, all of which were in the F-100. On October 24, 2000, he underwent his most recent FAR Part121 proficiency check. AIRCRAFT INFORMATION The Fokker F28 Mk 0100 airplane (serial number 11457) was delivered new to American Airlines, and had accumulated a total of 20,758 flight hours at the time of the accident. The airplane was maintained in accordance with American Airline's FAA approved airworthiness inspection program (AAIP). The nose landing gear (NLG) is an oleo-pneumatic shock-absorber, which absorbs loads and gives support to the airplane's nose. The NLG folds forward (toward the direction of flight) when it is retracted. When the landing gear lever in the cockpit is moved to the up (retract) position, a mechanical linkage acts to retract a down-lock plunger from a down-lock bracket in the nose landing gear bay, therefore releasing the nose landing gear from the down-and-locked position. The airplane's most recent light "C" maintenance check was completed on October 3, 2003, 1.1 hours prior to the accident. A review of the repair items, that were accomplished during the check, revealed the down-lock plunger would not fully extend into the down-lock bracket (therefore the NLG was not down-and-locked). Maintenance personnel noted the down-lock plunger clearance was greater than 0.02 inches (acceptable clearance is 0.003 - 0.02 inches). Maintenance personnel accomplished adjustments per the maintenance manual, which consisted of removing an unknown number of down-lock thrust shim plates. It should be noted that removal of the shims would further increase the clearance. However, subsequently the NLG was operated (retracted and extended 2-3 times) and the down-lock plunger was able to fully extend. The Fokker 100 maintenance manual (towing maintenance procedures) outlines steps to follow when towing the airplane with a NLG unsafe indication. The maintenance manual sets forth 4 different methods for towing; 1. Tow the aircraft from the nose landing gear 2. Tow the aircraft from the main landing gear 3. Tow the aircraft by main gear driving 4. Tow the aircraft from the nose landing gear with a towless towing vehicle. Each of these procedures contains a caution statement consisting of the following: DO NOT TOW THE AIRCRAFT IF A NOSE GEAR UNSAFE CONDITION IS GIVEN. THE DOWNLOCK PLUNGER IS NOT FULLY ENGAGED. THE NOSE LANDING GEAR CAN RETRACT. The manual states that a towing bridle (including straps) and tow bar must be available. The procedures further require the bridle be secured to the airplane prior to commencing the tow. The following warning is stated in American Airline's F-100 Operating Manual (Gear Up/Unsafe Ldg Procedure): "If nose gear unsafe indication is still present after landing, do not tow the airplane. Installation of the nose gear locking pin does not protect against nose gear collapse in this condition." DAMAGE TO AIRCRAFT Examination of the airplane, by the NTSB Investigator-In-Charge (IIC), revealed a semi-circular indentation (consistent with the dimensions of the tow bar) which initiated at the nose landing gear wheel well and extended forward, toward the direction of flight. The pressure bulkhead (item 260, according to the Fokker 100 structural repair manual), located forward of the nose landing gear wheel well, was wrinkled and ruptured. Additionally, the forward avionics door and an area of the fuselage, aft of the nose radome, were damaged. AERODROME INFORMATION The DFW Airport is located at north 32 degrees 47.042 minutes latitude and west 097 degrees 15.205 minutes longitude, and at an elevation of 602 feet msl. The airport has two parallel runways on the west side of the airport and three parallel runways on the east side of the airport that are oriented north-south. DFW also has two parallel runways oriented northwest-southeast. Runway 13R is concrete-grooved, and 9,301 feet long and 150 feet wide. METEOROLOGICAL INFORMATION ## Aircraft - Registration: [N1448A](https://openairdocs.org/deregistered/N1448A-2006-02-21), registration cancelled 2006-02-21, S/N 11457, built 1993 (OpenAirDocs) - Reported make and model: Fokker F28 Mk 0100 - Registry model: [Fokker F.28 MK 0100](https://openairdocs.org/model/fokker-f-28-mk-0100) (registry code 4990807) (OpenAirDocs) - Category: Airplane - Serial number: 11457 - Airframe hours: 20578 - Engines: Rolls-Royce TAY-650-1 15100 lbs thrust turbo fan - Damage: Substantial damage - Flight: Part 121 - Registered owner: American Airlines Inc. - Airworthiness certificate: Standard, Transport - Last inspection: Continuous airworthiness, October 2, 2001, 1.11 hours before - Departed: TUL, Tulsa, OK - Destination: DFW, DFW Airport, TX - Flight plan: IFR - Airport: DFW, Dallas-Fort Worth Intl, runway 13R, 9,301 × 150 ft, concrete ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 53; injuries: none; airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; last flight review February 6, 2001; seat: left; flight hours: 7,109 total, 5,286 in this make and model, 994 as pilot in command, 126 in the last 90 days, 71 in the last 30 days, 1 in the last 24 hours - Co-pilot; age 39; injuries: none; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; last flight review October 24, 2000; seat: right; flight hours: 413 total, 413 in this make and model, 92 in the last 90 days, 30 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 190° at 8 knots - Visibility: 8 statute miles - Lowest ceiling: none - Temperature: 64 °F, dew point 61 °F - Altimeter: 30.10 inHg - Observed at: DFW ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20011003037319A](https://openairdocs.org/incident/20011003037319A), Oct 3, 2001: Fokker F28MK0100, Dallas-Ft Worth, TX, No damage. (-23) On October 3, 2001, prior to landing at dfw and following gear extension a message appeared on the mfdu indicating the nose landing gear was unsafe.… 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.