# NTSB DEN05LA077: McDonnell Douglas MD-88, N949DL, Denver, CO, May 14, 2005 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: May 13, 2005, 18:20 local (May 14, 2005, 00:20 UTC) - Place: Denver, CO - Coordinates: 39.790969, -104.700775 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.7910&lon=-104.7008&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 98 uninjured - Status: Completed, report October 27, 2005 - Report: Approved by Office Director - Parties: Denver - NTSB case key (mKey): 61513 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN05LA077 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/61513/pdf - Page: https://openairdocs.org/ntsb/DEN05LA077 ## Probable cause the failure of the nose gear actuator resulted in penetration of the forward pressure bulkhead and a loss of pressurization. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, takeoff - initial climb - landing gear,nose gear assembly - worn - landing gear,nose gear assembly - failure (cause) - Decompression, takeoff - initial climb - fuselage,pressure bulkhead - penetrated (cause) ## Analysis Shortly after takeoff, the pilots heard a loud bang and the cabin lost pressurization. The pilots observed an unsafe nose gear indication. They placed the gear handle in the down position and got three green lights. The control tower confirmed that the landing gear were down when the aircraft performed a low pass. The flight made an uneventful landing at Denver. Post-accident examination by maintenance personnel revealed a hole in the forward pressure bulkhead and broken nose gear actuator. The nose landing gear actuator piston rod had worn threads, and a key locking washer in the gear assembly was sheared. The airline said that this was original equipment. ## Factual narrative On May 13, 2005, approximately 1820 mountain daylight time, a McDonnell-Douglas MD-88, N949DL, operated by Delta Air Lines as flight 664, was substantially damaged when the forward pressure bulkhead was penetrated by the nose landing gear actuator rod during initial climb near Denver, Colorado. Visual meteorological conditions prevailed at the time of the accident. The flight was being conducted on an instrument flight rules flight plan under the provisions of 14 CFR Part 121. The 2 pilots, 3 flight attendants, and 93 passengers were not injured. The flight originated at Denver International Airport (DEN), Denver, Colorado, and was en route to Hartsfield International Airport (ATL), Atlanta, Georgia. Shortly after takeoff, the pilots heard a loud bang and the cabin lost pressurization. The pilots observed an unsafe nose gear indication. They placed the gear handle in the down position and got three green lights. The control tower confirmed that the landing gear were down when the aircraft performed a low pass. The flight made an uneventful landing at Denver Post-accident examination by maintenance personnel revealed a hole in the forward pressure bulkhead and broken nose gear actuator. The nose landing gear actuator piston rod had worn threads, and a key locking washer in the gear assembly was sheared. At the time of the accident, the aircraft had accumulated 41,789.9 hours and 32,669 cycles. According to Delta Air Lines, there was no maintenance history on the actuator, and they believed it was original equipment when the aircraft was delivered in February 1990. An FAA Airworthiness Directive required the material composition of the nose landing gear lock link be determined. Delta Air Lines provided maintenance records proving the aircraft was in compliance with this Directive. ## Aircraft - Registration: [N949DL](https://openairdocs.org/deregistered/N949DL-2022-04-25), registration cancelled 2022-04-25, S/N 49880, built 1990 (OpenAirDocs) - Reported make and model: McDonnell Douglas MD-88 - Registry model: [Mcdonnell Douglas MD-88](https://openairdocs.org/model/mcdonnell-douglas-md-88) (registry code 3023688) (OpenAirDocs) - Registry engine: [Pratt & Whitney JT8D series](https://openairdocs.org/engine/pratt-whitney-jt8d-series) (registry code 52053, turbo-jet) (OpenAirDocs) - Category: Airplane - Serial number: 49880 - Airframe hours: 41789 - Engines: Pratt & Whitney JT8D-219 21000 lbs thrust turbo fan; Pratt & Whitney JT8D-219 21000 lbs thrust turbo fan - Damage: Substantial damage - Flight: Part 121 - Registered owner: On FIle - Airworthiness certificate: Standard, Transport - Last inspection: Continuous airworthiness, May 1, 2005 - Departed: DEN, Denver, CO - Destination: ATL, Atlanta, GA - Flight plan: IFR - Airport: DEN, Denver International ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 45; injuries: none; airline transport, flight engineer; airplane ratings: multi-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review December 1, 2004; seat: left; flight hours: 7,774 total, 681 in this make and model - Co-pilot; age 36; injuries: none; airline transport, flight instructor; airplane ratings: multi-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review July 1, 2004; seat: right; flight hours: 3,101 total, 2,483 in this make and model ## Weather - Conditions: Visual (VMC), Not reported - Wind: 40° at 8 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 63 °F, dew point 30 °F - Altimeter: 30.12 inHg - Observed at: DEN ## 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 20050513008879A](https://openairdocs.org/incident/20050513008879A), May 13, 2005: Doug MD88, Denver, CO, Substantial damage. (-23) Flight crew heard loud bang when retraction was attempted. Nose landing gear would not lock up. Landing gear was placed back into the down position. Got… 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.