# NTSB FTW98IA361: Piper PA-31-350, N66906, Denver, CO, August 18, 1998 - Type: NTSB incident investigation - Classification: Incident · No injuries · Incident investigation · Final report - Date: August 17, 1998, 21:05 local (Aug 18, 1998, 03:05 UTC) - Place: Denver, CO - Coordinates: 39.850383, -104.699645 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.8504&lon=-104.6996&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report May 19, 1999 - Report: Approved by Office Director - NTSB case key (mKey): 43665 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW98IA361 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/43665/pdf - Page: https://openairdocs.org/ntsb/FTW98IA361 ## Probable cause A hydraulic failure due to a ruptured hydraulic line, preventing the extension of the nose and right main landing gear. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, cruise - hydraulic system,line - failure (cause) - gear extension - not possible, pilot in command - Wheels up landing, emergency landing - wheels up landing - performed, pilot in command ## Analysis After departure, the crew noticed a malfunction with the landing gear transition light. They attempted to recycle the landing gear, but the transition light remained illuminated. They circled the area for approximately one hour and thirty-five minutes, but all attempts to lower the gear were unsuccessful. The crew made the decision to divert to Denver International Airport where expanded emergency ground services would be available. The crew declared an emergency, and a gear-up landing was performed. Post accident examination of the aircraft by an FAA inspector revealed that the landing gear sustained a hydraulic failure which was due to a ruptured hydraulic hose located in the right wheel well. The hydraulic braided steel hose had several braids broken and the rubber hose had been punctured and/or ruptured under pressure. ## Factual narrative On August 17, 1998, approximately 2105 mountain daylight time, a Piper PA-31-350, N66906, sustained minor damage during an emergency landing at Denver International Airport, Denver, Colorado. The commercial pilot and copilot were not injured. The flight was being operated by Alliance Aviation, Inc., under Title 14 CFR Part 135, and an IFR flight plan had been filed. Visual meteorological conditions prevailed for the cargo flight which originated at Perry Stokes Airport, Trinidad, Colorado, at 1805, with an intended destination of Colorado Springs Municipal Airport, Colorado Springs, Colorado. According to the pilot-in-command, after departing Perry Stokes Aiprort, he and his co-pilot noticed a malfunction with the landing gear transition light. They attempted to recycle the landing gear, but the transition light remained illuminated. They notified the Colorado Springs tower and performed a fly by. The tower was able to visually verify that the left landing gear was down, and the right and nose landing gear remained in the up position. The crew circled the area for approximately one hour and thirty-five minutes, but all attempts to lower the gear by means of aerial maneuvers and emergency gear extension were unsuccessful. The crew made the decision to divert to Denver International Airport where expanded emergency ground services would be available. The crew declared an emergency, and a gear-up landing was performed. The aircraft came to rest approximately 2,500 from the threshold of runway 17L, 50 feet to the right of the centerline. The aircraft sustained minor damage to the right engine propeller blades. Post accident examination of the aircraft by an FAA inspector revealed that the landing gear sustained a hydraulic failure which was due to a ruptured hydraulic hose located in the right wheel well. The hydraulic braided steel hose had several braids broken and the rubber hose had been punctured and/or ruptured under pressure. ## Aircraft - Registration: [N66906](https://openairdocs.org/deregistered/N66906-2016-08-10), registration cancelled 2016-08-10, S/N 31-7405197, built 1974 (OpenAirDocs) - Reported make and model: Piper PA-31-350 - Registry model: [Piper PA-31-350](https://openairdocs.org/model/piper-pa-31-350) (registry code 7103110) (OpenAirDocs) - Registry engine: [Lycoming TI0-540 series](https://openairdocs.org/engine/lycoming-ti0-540-series) (registry code 41533, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: 31-7405197 - Airframe hours: 13201 - Engines: Lycoming TIO-540-J2BD 350 horsepower reciprocating - Damage: Minor damage - Flight: Part 135 - Registered owner: Alliance Aviation, Inc. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, August 3, 1998, 50 hours before - Departed: TAD, TRINIDAD, CO - Destination: COS, COLORADO SPRNGS, CO - Flight plan: IFR - Airport: DEN, Denver International, runway 17L, 12,000 × 150 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 32; commercial, flight instructor; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 1,415 total, 160 in this make and model, 1,226 as pilot in command, 160 in the last 90 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Night/bright - Wind: 210° at 12 knots - Visibility: 10 statute miles - Lowest ceiling: 20,000 ft broken - Temperature: 73 °F, dew point 52 °F - Altimeter: 30.00 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). - [Incident 19980817036389I](https://openairdocs.org/incident/19980817036389I), Aug 17, 1998: Piper PA31350, Denver, CO, Minor damage. The aircraft departed from trinidad, Colorado operating under title 14 part 135 cargo operations. During climb out the crew noticed that the right main gear… ## Other investigations on N66906 (1) 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. - [NTSB CEN15LA117](https://openairdocs.org/ntsb/CEN15LA117), Jan 21, 2015: Piper PA-31-350 (N66906), Goodland, KS, substantial damage. Probable cause: The pilot's improper fuel management and failure to conduct the engine failure emergency procedures and his improper conduct of the forced landing, which resulted in fuel starvation, a total loss of… 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.