# NTSB WPR12LA030: Piper PA-31T, N39EH, Cheyenne, WY, November 8, 2011 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: November 8, 2011, 11:00 local (18:00 UTC) - Place: Cheyenne, WY - Coordinates: 41.155555, -104.810279 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=41.1556&lon=-104.8103&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338) - Highest injury: No injuries - Injuries: 4 uninjured - Status: Completed, report August 29, 2013 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 82275 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR12LA030 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/82275/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=82275 - Page: https://openairdocs.org/ntsb/WPR12LA030 ## Probable cause The flight crew’s failure to properly latch the cabin door before takeoff. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Doors: passenger/crew doors](https://openairdocs.org/ntsb-findings/01035210): Aircraft › Aircraft structures · Incorrect use/operation (probable cause); cases with it: [Piper PA-31T, 1 case](https://openairdocs.org/ntsb-findings/01035210/cases.md?model=7103124), [All aircraft, 86 cases](https://openairdocs.org/ntsb-findings/01035210/cases.md) - [Use of equip/info: use of equip/system](https://openairdocs.org/ntsb-findings/02063015): Personnel issues › Task performance · Flight crew (probable cause); cases with it: [Piper PA-31T, 1 case](https://openairdocs.org/ntsb-findings/02063015/cases.md?model=7103124), [All aircraft, 1,391 cases](https://openairdocs.org/ntsb-findings/02063015/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Initial climb: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338) (defining event); cases with it: [Piper PA-31T, 3 cases](https://openairdocs.org/ntsb-events/338/sequence.md?model=7103124), [All aircraft, 563 cases](https://openairdocs.org/ntsb-events/338/sequence.md) ## Analysis The airplane was climbing through 7,500 feet when the main cabin door opened in-flight and subsequently separated from the airframe. The main cabin door was later recovered and examined. The examination revealed deformation on the outer skin on the lower end of the door; the skin deformation was consistent with the door rotating downward and aft relative to the hinge attachment. The fracture surfaces were on slant planes consistent with ductile overstress fracture. No evidence of preexisting cracks was observed. The door latching mechanism was examined and all pushrods, latch pins, and the associated bellcrank were in place and intact. Wear was observed on the upper side of the forward pins at the middle and upper positions; however, the latching mechanism travel and extension of the latch pins was correct. No other anomalies were noted; thus it is likely the door latch mechanism was not fully engaged before takeoff, which resulted in the door opening in-flight. ## Factual narrative On November 8, 2011 about 1100 mountain standard time, the pilot of a Piper PA-31T Cheyenne II, N39EH, made a precautionary landing at Cheyenne Regional/Jerry Olson Field Airport (CYS), Cheyenne, Wyoming, after the airplane’s main cabin door separated from the airframe in-flight about 20 miles north of the airport. The airline transport pilot, two crew members and passenger were not injured and the airplane sustained substantial damage to the aft fuselage door frame assembly. The airplane was registered to La Stella of Wilmington, Delaware and operated by Travelaire Service, Inc, Pueblo, Colorado. The on-demand air medical flight was operated under the provisions of 14 Code of Federal Regulations Part 135. Visual meteorological conditions prevailed and an instrument flight rules flight plan was filed for the cross country flight. The flight originated from Cheyenne Regional/Jerry Olson Field Airport (CYS) about 1040 with a planned destination of Sheridan, Wyoming (SHR). The pilot reported that the airplane was climbing through 7,500 feet, for 12,500 feet, when he noted a pressurization issue and leveled the airplane at 8,500 feet. He consulted the checklist; however, was not able to rectify the situation and initiated a turn back to the departure airport. Soon thereafter, the airplane’s master caution horn sounded and the door unsafe light illuminated followed by a rush of air in the cockpit. The pilot returned to the departure airport and landed without further incident. The medical flight crew reported that about 20 minutes after takeoff, the main cabin door opened in-flight; the door subsequently separated from the aircraft. The main cabin door was later recovered and examined by a senior materials engineer at the National Transportation Safety Board’s materials laboratory, Washington DC. The examination revealed that the door hinge was fractured from the lower end of the door, and the hinge remained attached to the airplane. Rivets at the forward end of the hinge line were fractured, and the door outer skin was fractured in the hinge rivet line. Skin fractured around several of the rivets, and the saw-tooth pattern of fracture around the rivets was consistent with fracture propagation from forward to aft. Deformation was observed on the outer skin on the lower end of the door; the skin deformation was consistent with the door rotating downward and aft relative to the hinge attachment. The fracture surfaces were examined and all surfaces showed deformation and/or features on slant planes consistent with ductile overstress fracture. No evidence of preexisting cracks was observed. Internal panels were disassembled from the door to view the door structure and latching mechanism. All pushrods, latch pins and associated bellcrank were in place and intact. Wear was observed on the upper side of the forward pins at the middle and upper positions; however, the latching mechanism travel and extension of the pins was correct. No other anomalies werenoted. A complete materials laboratory examination report is contained in the public docket for this accident. ## Aircraft - Registration: [N39EH](https://openairdocs.org/aircraft/N39EH), registered now, S/N 31T-7920020, built 1978 (OpenAirDocs) - Reported make and model: PIPER PA-31T - Registry model: [Piper PA-31T](https://openairdocs.org/model/piper-pa-31t) (registry code 7103124) (OpenAirDocs) - Registry engine: [Pratt & Whitney Canada PT6A-60A](https://openairdocs.org/engine/pratt-whitney-canada-pt6a-60a) (registry code 52043, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: 31T-7920020 - Airframe hours: 6345 - Engines: P&W CANADA PT6A-60A 1050 horsepower turbo prop; P&W CANADA PT6A-60A 1050 horsepower turbo prop - Damage: Substantial damage - Flight: Part 135 - Operator: Travelaire Service Inc - Registered owner: La Stella - Airworthiness certificate: Standard, Normal - Last inspection: Unknown, July 7, 2011 - Departed: CYS, Cheyenne, WY - Destination: SHR, Sheridan, WY - Flight plan: IFR - Airport: CYS, Cheyenne Regional Airport ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 46; injuries: none; airline transport; airplane ratings: multi-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review May 2, 2011; seat: left; flight hours: 4,985 total, 3,219 in this make and model, 3,450 as pilot in command, 230 in the last 90 days, 48 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 330° at 11 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 36 °F, dew point 16 °F - Altimeter: 30.10 inHg - Observed at: CYS, 20 nm away ## 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 20111108026539A](https://openairdocs.org/incident/20111108026539A), Nov 8, 2011: Piper PA-31T, Cheyenne, WY, Substantial damage. On 8 November 2011, at approximately 1100 hrs MST, during climb out from Cheyenne (cys) airport, WY, N39EH, a Piper model PA-31T Cheyenne aircraft sustained… ## Docket (4 files) The files NTSB released with the investigation on June 21, 2013, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=82275. 3.7 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 731 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40358888&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Crew Statements (item 2, .PDF, 498 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40358889&FileExtension=.PDF&FileName=Crew%20Statements-Redacted.PDF - Materials Laboratory 15 - Factual Report 13-017 (16 Embedded Images) (item 3, .PDF, 16 photos, 2.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40389325&FileExtension=.PDF&FileName=Materials%20Laboratory%2015%20-%20Factual%20Report%2013-017%20(16%20Embedded%20Images)-Master.PDF - Evidence Control Form (item 4, .PDF, 87 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40395424&FileExtension=.PDF&FileName=Evidence%20Control%20Form-Redacted.PDF 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.