# NTSB WPR09IA187: Liberty Aerospace Liberty XL-2, N519XL, Camarillo, CA, April 5, 2009 - Type: NTSB incident investigation - Classification: Incident · No injuries · Incident investigation · Final report - Date: April 5, 2009, 11:30 local (18:30 UTC) - Place: Camarillo, CA - Coordinates: 34.2, -119.033332 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=34.2000&lon=-119.0333&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report April 22, 2010 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration, Liberty Aerospace, Inc. - NTSB case key (mKey): 73627 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR09IA187 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/73627/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=73627 - Page: https://openairdocs.org/ntsb/WPR09IA187 ## Probable cause The cruise flight separation of the canopy door. Contributing to the incident was the pilot's failure to ensure that the left side door was securely closed prior to 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 · Failure (probable cause); cases with it: [Liberty Aerospace LIBERTY XL-2, 1 case](https://openairdocs.org/ntsb-findings/01035210/cases.md?model=5200000), [All aircraft, 86 cases](https://openairdocs.org/ntsb-findings/01035210/cases.md) - [Turbulence: clear air turbulence](https://openairdocs.org/ntsb-findings/03032015): Environmental issues › Conditions/weather/phenomena · Not specified; cases with it: [Liberty Aerospace LIBERTY XL-2, 1 case](https://openairdocs.org/ntsb-findings/03032015/cases.md?model=5200000), [All aircraft, 78 cases](https://openairdocs.org/ntsb-findings/03032015/cases.md) - [Inspection: preflight inspection](https://openairdocs.org/ntsb-findings/02061510): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Liberty Aerospace LIBERTY XL-2, 1 case](https://openairdocs.org/ntsb-findings/02061510/cases.md?model=5200000), [All aircraft, 551 cases](https://openairdocs.org/ntsb-findings/02061510/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Standing-engine(s) operating: Miscellaneous/other](https://openairdocs.org/ntsb-events/900); cases with it: [Liberty Aerospace LIBERTY XL-2, 3 cases](https://openairdocs.org/ntsb-events/900/sequence.md?model=5200000), [All aircraft, 1,556 cases](https://openairdocs.org/ntsb-events/900/sequence.md) - [Enroute-cruise: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338) (defining event); cases with it: [Liberty Aerospace LIBERTY XL-2, 1 case](https://openairdocs.org/ntsb-events/338/sequence.md?model=5200000), [All aircraft, 563 cases](https://openairdocs.org/ntsb-events/338/sequence.md) ## Analysis Prior to takeoff, the pilot, who was receiving instrument flight instruction, closed the left side canopy door. The door is composed of a composite material that can be torsionally deformed during the closing and locking process if both the forward and rear door pins are not fully engaged in their respective fuselage frame receptacles. During the door closing operation, the door's aft locking pin was not completely engaged into its receptacle in the door frame. The airplane's flight manual's "Before Takeoff" checklist contains the line item that the doors are to be "CLOSED AND SECURE." The pilot and flight instructor departed for the flight and initially the left side door remained closed; however, the door popped open when the airplane entered an area of moderate turbulence. Thereafter, the left side door's structure ripped apart with the majority of the door separating from the airplane. A portion of the door impacted and dented the left stabilator, and a portion of the door became lodged in the airplane's empennage. The flight instructor took control of the airplane and, unable to maintain altitude, descended and landed at a nearby airport without further incident. After this event, the airplane's manufacturer enhanced the checklist to include the following statement: "Canopy Doors (Both FWD pins and both AFT pins) ENGAGED AND SECURE. [[NOTE]] Verify doors are closed by pushing on aft section of both doors." Also, the manufacturer issued Service Document number SB-09-003, indicating the availability of a tapered aft actuator door pin that, when installed, will facilitate the door's locking pins' engagement into the door frame receptacle. ## Factual narrative HISTORY OF FLIGHT On April 5, 2009, about 1130 Pacific daylight time, a Liberty Aerospace, Inc., Liberty XL-2, N519XL, experienced the loss of the majority of its left side cockpit door during cruise flight about 3 miles east of the Camarillo Airport, Camarillo, California. Separated door components impacted and dented the airplane's left stabilator. The airplane was operated by the Armed Forces Aero Club, Inc., San Diego, California, and it sustained minor damage during the incident. Visual meteorological conditions prevailed at the time, and an instrument flight rules flight plan had been filed. Neither the certified flight instructor (CFI), who held an airline transport pilot certificate, nor the private pilot, who was receiving instruction, was injured. The flight was performed under the provisions of 14 Code of Federal Regulations Part 91 and originated from San Diego about 1000. The CFI reported to the National Transportation Safety Board investigator that the airplane's pre-takeoff checklist was followed. The CFI opined that the student properly and securely closed the left cockpit door prior to takeoff. No discrepancies were noted with the door's operation. At no time during the instrument training flight did the student open or attempt to open the door. According to the CFI, when the incident occurred the student was receiving instrument flight instruction and was tracking inbound on the localizer to the Oxnard Airport, which is located a few miles west of Camarillo. The airplane was cruising in level flight about 4,000 feet mean sea level. The student's left hand was holding the control stick. The door "popped open" minutes after the airplane entered an area of moderate clear air turbulence. Thereafter, the door separated from the airplane, and the CFI took control of the airplane. Observing that the nearest airport was Camarillo, the CFI diverted to that airport. The CFI stated to the Safety Board investigator that despite application of full engine power, level flight could not be maintained. Fortunately, because of their close proximity to the Camarillo Airport, they were able to immediately land without further mishap. As the airplane taxied to parking, the local air traffic controller advised them that an airframe component had dropped from their airplane onto the tarmac. Subsequently, the component was recovered from the tarmac and was noted to be the lower portion of the separated door, which included the latching mechanism. The CFI opined that the component must have become attached to a portion of the airframe structure after it ripped off from the upper portion of the door. The upper portion of the door had remained attached to the airframe by its hinges. PERSONNEL INFORMATION The CFI reported that his total flight time is 14,469 hours. His total flight time in the Liberty XL-2 is 34 hours. The student's total flight time is 181 hours. The student's flight time in the Liberty XL-2 is 38 hours. AIRCRAFT INFORMATION The SafetyBoard investigator examined the normal category airplane, serial number 14. The airplane was manufactured and issued a standard Federal Aviation Administration (FAA) airworthiness certificate on April 18, 2006. By the accident date, the 3-year-old airplane's total time was about 253 hours. Its last annual inspection was accomplished in July 2008, at a total time of 178 hours. The airplane was designed with two doors that attach to the airframe with hinges located on their upper (top) surface. The doors are secured in the locked position by engagement of 2 locking pins. One pin extends from the body of the front portion of the door frame into a receptacle located in the fuselage structure, adjacent to the front of the door. The other pin extends from the body of the aft portion of the door frame into a receptacle located in the fuselage structure, adjacent to the rear of the door. To close the door, the occupant rotates the door handle into the forward, closed position. This action extends the locking pins from inside the door into the fuselage receptacles and secures the door. WRECKAGE AND IMPACT INFORMATION The Safety Board investigator examined both the right side cockpit door, which was not damaged, and the left side cockpit (incident) door. The right side cockpit door's latching mechanism was found functional. The fuselage structure adjacent to the door's forward and rear pin receptacles was found abraded, and evidence of chipped paint was noted in these areas. The marks were consistent with impact damage resulting from the door being partially closed with the locking pins extended. The Safety Board investigator noted that if an attempt is made to close the door with the locking pins extended, the sides of the pins contact the side of the fuselage receptacles, and the pins do not enter the receptacles to secure the door in a locked position. Similar impact marks were noted in the left side fuselage, adjacent to the incident door's forward and aft locking pins. The left (incident) door was observed broken into several pieces. By design, the airplane's doors are constructed of a composite material. The Safety Board investigator noted that when the door is open, the body of the door is not rigid, and the door's frame can be torsionally twisted by application of force on either the door's lower front or lower rear surface. TESTS AND RESEARCH At the Safety Board investigator's request, the Liberty Aerospace manufacturer's participant compiled and evaluated reports of other inadvertent openings of canopy doors. The participant reported that its review of data indicated about 6 instances wherein a canopy door had opened during flight. The participant concluded that in these instances, a door pin had likely not been seated in its receptacle. This condition likely allowed the canopy door to open in flight. While participating in the Safety Board's investigation, Liberty Aerospace evaluated the door's design and locking mechanism. The participantreported that Liberty's research validated its original design, which indicated that if both the forward and aft locking pins are properly engaged, the door and airframe can not flex and allow the disengagement of a door pin. Liberty's evaluation further indicated that if one of the two door pins on a door is not in its receptacle when the door is closed, the door could flex and open. ADDITIONAL INFORMATION A review of the airplane's FAA approved flight manual (AFM) current on the April 5, 2009, date of this incident revealed it contained a "BEFORE TAKEOFF" checklist. In the checklist it states "Canopy Doors...CLOSED AND SECURE." The manufacturer reported that, in response to information learned during this and other investigations, it revised the AFM checklists for the Liberty XL-2. The revisions were made to further enhance safety. The revisions include specific language requiring the verification of each individual door pin engagement prior to takeoff. The revised checklist states: "Canopy Doors (both FWD pins and both AFT pins) ENGAGED AND SECURE. [[NOTE]] Verify doors are closed by pushing on aft section of both doors." Also, as a further precautionary measure, the manufacturer procured a tapered door pin for installation in the aft portion of the door. The new tapered pin has an offset at its end to assist the capture of the fuselage receptacle when the door pin is moved into the closed position. The newly designed pin will be utilized in the manufacture of all future Liberty XL-2 airplanes, in addition to being made available to owners of previously manufactured airplanes through a Service Document. Service Document number SB-09-003 was issued on December 15, 2009. In part, it states the following: "To ensure that the aircraft’s doors are properly closed, latched and locked, the forward and aft pins must both be seated in their respective receptacles. If a pin is not properly seated in its receptacle, the door is not secure and could open in flight resulting in possible door and aircraft damage." ## Aircraft - Registration: [N519XL](https://openairdocs.org/deregistered/N519XL-2024-03-16), registration cancelled 2024-03-16, S/N 0014, built 2006 (OpenAirDocs) - Reported make and model: LIBERTY AEROSPACE INCORPORATED LIBERTY XL-2 - Registry model: [Liberty Aerospace LIBERTY XL-2](https://openairdocs.org/model/liberty-aerospace-liberty-xl-2) (registry code 5200000) (OpenAirDocs) - Registry engine: [Continental IO-240-B](https://openairdocs.org/engine/continental-io-240-b) (registry code 17177, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 0014 - Airframe hours: 253 - Engines: Continental IOF-240-B 125 horsepower reciprocating - Damage: Minor damage - Flight: Instructional, Part 91 - Operator: Armed Forces Flying Club, Inc. - Registered owner: Myf - Xl2 Inc - Airworthiness certificate: Standard, Normal - Last inspection: Annual, July 1, 2008, 75 hours before - Departed: MYF, San Diego, CA - Destination: OXR, Oxnard, CA - Flight plan: IFR - Airport: CMA, Camarillo ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 67; injuries: none; flight engineer, flight instructor, airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; last flight review June 30, 2008; seat: right; flight hours: 14,469 total, 34 in this make and model, 13,747 as pilot in command, 100 in the last 90 days, 41 in the last 30 days, 1 in the last 24 hours - Student pilot; age 22; injuries: none; private; airplane ratings: single-engine land; medical: class 3, without waivers/limitations; last flight review May 3, 2008; seat: left; flight hours: 181 total, 88 in this make and model, 112 as pilot in command, 46 in the last 90 days, 4 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 80° at 8 knots, gusting 16 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 66 °F, dew point 30 °F - Altimeter: 30.00 inHg - Observed at: CMA, 3 nm away ## Docket (25 files) The files NTSB released with the investigation on January 27, 2010, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=73627. 10.8 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 395 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323726&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Statement of Party Representatives to NTSB Investigation (item 2, .PDF, 404 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323727&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-Redacted.PDF - Liberty XL-2 Engine Runup Checklist (rev) (item 3, .PDF, 41 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323729&FileExtension=.PDF&FileName=Liberty%20XL-2%20Engine%20Runup%20Checklist%20(rev)-Master.PDF - Liberty XL-2 Before Takeoff Checklist (rev) (item 4, .PDF, 34 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323731&FileExtension=.PDF&FileName=Liberty%20XL-2%20Before%20Takeoff%20Checklist%20(rev)%20-Master.PDF - Liberty Service Document SB-09-003 (item 5, .PDF, 224 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323733&FileExtension=.PDF&FileName=Liberty%20Service%20Document%20SB-09-003-Master.PDF - Photo 1. Left door fragment (bottom) found separated from aircraft. (item 6, .PDF, 487 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323736&FileExtension=.PDF&FileName=Photo%201.%20Left%20door%20fragment%20(bottom)%20found%20separated%20from%20aircraft.-Master.PDF - Photo 2. Left door fragment (top) remained attached to aircraft. (item 7, .PDF, 33 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323737&FileExtension=.PDF&FileName=Photo%202.%20Left%20door%20fragment%20(top)%20remained%20attached%20to%20aircraft.-Master.PDF - Photo 3. Left side of aircraft with broken door. (item 8, .PDF, 787 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323739&FileExtension=.PDF&FileName=Photo%203.%20Left%20side%20of%20aircraft%20with%20broken%20door.-Master.PDF - Photo 4. Left side of aircraft, missing door. (item 9, .PDF, 794 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323741&FileExtension=.PDF&FileName=Photo%204.%20Left%20side%20of%20aircraft,%20missing%20door.-Master.PDF - Photo 5. Left front door pin engagement hole. (item 10, .PDF, 667 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323744&FileExtension=.PDF&FileName=Photo%205.%20Left%20front%20door%20pin%20engagement%20hole.-Master.PDF - Photo 6. Left front engagement hole, close up. (item 11, .PDF, 328 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323745&FileExtension=.PDF&FileName=Photo%206.%20Left%20front%20engagement%20hole,%20close%20up.-Master.PDF - Photo 7. Left rear door pin engagement hole. (item 12, .PDF, 714 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323748&FileExtension=.PDF&FileName=Photo%207.%20Left%20rear%20door%20pin%20engagement%20hole.-Master.PDF - Photo 8. Left rear engagement hole, close up. (item 13, .PDF, 305 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323750&FileExtension=.PDF&FileName=Photo%208.%20Left%20rear%20engagement%20hole,%20close%20up.-Master.PDF - Photo 9. Right front door pin engagement hole. (item 14, .PDF, 743 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323752&FileExtension=.PDF&FileName=Photo%209.%20Right%20front%20door%20pin%20engagement%20hole.-Master.PDF - Photo 10. Right front engagement hole, close up. (item 15, .PDF, 426 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323754&FileExtension=.PDF&FileName=Photo%2010.%20Right%20front%20engagement%20hole,%20close%20up.-Master.PDF - Photo 11. Right rear door pin engagement hole. (item 16, .PDF, 704 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323756&FileExtension=.PDF&FileName=Photo%2011.%20Right%20rear%20door%20pin%20engagement%20hole.-Master.PDF - Photo 12. Right rear engagement hole, close up. (item 17, .PDF, 452 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323757&FileExtension=.PDF&FileName=Photo%2012.%20Right%20rear%20engagement%20hole,%20close%20up.-Master.PDF - Photo 13. Left stabilator, leading edge dent. (item 18, .PDF, 21 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323758&FileExtension=.PDF&FileName=Photo%2013.%20Left%20stabilator,%20leading%20edge%20dent.-Master.PDF - Photo 14. Stabilator leading edge showing door impact dent. (item 19, .PDF, 394 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323759&FileExtension=.PDF&FileName=Photo%2014.%20Stabilator%20leading%20edge%20showing%20door%20impact%20dent.-Master.PDF - Photo 15. Stabilator leading edge, front view. (item 20, .PDF, 192 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323760&FileExtension=.PDF&FileName=Photo%2015.%20Stabilator%20leading%20edge,%20front%20view.-Master.PDF - Photo 16. Stabilator, outboard end. (item 21, .PDF, 779 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323761&FileExtension=.PDF&FileName=Photo%2016.%20Stabilator,%20outboard%20end.-Master.PDF - Photo 17. Stabilator, inboard end. (item 22, .PDF, 339 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323762&FileExtension=.PDF&FileName=Photo%2017.%20%20Stabilator,%20inboard%20end.-Master.PDF - Photo 18. Stabilator, side view. (item 23, .PDF, 628 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323763&FileExtension=.PDF&FileName=Photo%2018.%20Stabilator,%20side%20view.-Master.PDF - Photo 19. Right door, inside view, locking lever in closed position. (item 24, .PDF, 466 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323764&FileExtension=.PDF&FileName=Photo%2019.%20Right%20door,%20inside%20view,%20locking%20lever%20in%20closed%20position.-Master.PDF - Photo 20. Right door, inside view, locking lever in open position. (item 25, .PDF, 437 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323765&FileExtension=.PDF&FileName=Photo%2020.%20Right%20door,%20inside%20view,%20locking%20lever%20in%20open%20position.-Master.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.