# NTSB CEN15TA035: Bell UH1H, N72595, San Isidro, TX, October 23, 2014 - Type: NTSB accident investigation - Classification: Accident · No injuries · Final report - Date: October 23, 2014, 14:00 local (19:00 UTC) - Place: San Isidro, TX - Coordinates: 26.550003, -98.71997 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=26.5500&lon=-98.7200&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed, report February 23, 2015 - Report: Approved by Office Director - NTSB office: Central Region - Parties: U. S. Customs and Border Protection, FAA Flight Standards - NTSB case key (mKey): 90334 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN15TA035 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/90334/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=90334 - Page: https://openairdocs.org/ntsb/CEN15TA035 ## Probable cause The flight crew's failure to ensure that the sliding cabin door was properly secured before the flight. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Inspection: preflight inspection](https://openairdocs.org/ntsb-findings/02061510): Personnel issues › Task performance · Flight crew (probable cause); cases with it: [Bell UH-1H, 2 cases](https://openairdocs.org/ntsb-findings/02061510/cases.md?model=1181407), [All aircraft, 551 cases](https://openairdocs.org/ntsb-findings/02061510/cases.md) - [Doors: passenger/crew doors](https://openairdocs.org/ntsb-findings/01035210): Aircraft › Aircraft structures · Incorrect use/operation (probable cause); cases with it: [Bell UH-1H, 1 case](https://openairdocs.org/ntsb-findings/01035210/cases.md?model=1181407), [All aircraft, 86 cases](https://openairdocs.org/ntsb-findings/01035210/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338) (defining event); cases with it: [Bell UH-1H, 6 cases](https://openairdocs.org/ntsb-events/338/sequence.md?model=1181407), [All aircraft, 563 cases](https://openairdocs.org/ntsb-events/338/sequence.md) - [Emergency descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Bell UH-1H, 3 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=1181407), [All aircraft, 3,368 cases](https://openairdocs.org/ntsb-events/440/sequence.md) ## Analysis Before the accident flight, the flight crew completed a routine law enforcement patrol flight without incident. That flight was conducted with the pilot, copilot, and main cabin quarter doors removed and the sliding main cabin doors in the "full open" position. After refueling the helicopter, the flight crew conducted a preflight inspection, during which, the copilot and a tactical team member (TTM) noted that the door latch pin was missing from the left sliding door latch. The TTM stated that the copilot advised him that the pin was not required to be installed. The copilot stated that he informed the pilot about the missing pin but that he was not sure that the pilot adequately understood him. About 15 minutes after departing, during cruise flight, the flight crew heard "a loud bang," and the pilot felt a momentary upset in the helicopter's flightpath. Although the helicopter operated normally after the event, the pilot chose to perform a precautionary landing to an open field. During the postflight inspection, the flight crew determined that the left sliding cabin door had separated from the helicopter. A postaccident examination did not reveal any anomalies consistent with a failure of the door assembly or airframe structure that would have led to the separation. The helicopter's Pilot's Operating Handbook stated that the helicopter could be flown up to 120 knots with an open door if it is in the "full open" position and secured by the door latch. The lack of the door latch pin allowed the door to slide forward during flight and then aerodynamic forces separated the door from the sliding track. ## Factual narrative On October 23, 2014, about 1400 central daylight time, a Bell model UH-1H helicopter, N72595, was substantially damaged when the left cabin sliding door separated during cruise flight and impacted one of the main rotor blades near San Isidro, Texas. The three crew members were not injured. The helicopter was registered to the U.S. Department of Homeland Security and operated by U.S. Customs and Border Protection under the provisions of 14 Code of Federal Regulations Part 91 as a public use flight. Visual meteorological conditions prevailed for the flight, which was not operated on a flight plan. The flight originated from the Brooks County Airport (BKS), Falfurrias, Texas, about 1345. The intended destination was the McAllen Miller International Airport (MFE), McAllen, Texas, after conducting a routine law enforcement patrol flight. The crew originally departed MFE about 1100 and completed a routine law enforcement patrol about 2 hours 15 minutes in duration without incident. The flight was operated with the pilot and co-pilot doors, and the main cabin quarter doors removed. The sliding main cabin doors were secured in the fully open position. The crew subsequently landed at BKS in order to refuel and eat lunch. After refueling, the crew conducted a preflight inspection. During that inspection, the co-pilot and tactical team member (TTM), who were inspecting the left side of the helicopter, noted that the open door latch pin was missing from the left sliding door latch. The TTM reportedly discussed the missing pin with the co-pilot. The TTM stated that the co-pilot advised him that the pin was not required to be installed. The co-pilot stated that he had informed the pilot about the missing pin, but he was not sure that the pilot adequately understood him. The crew reported that about 15 minutes after departing BKS, during cruise flight, they heard a loud bang and the pilot felt a momentary upset in the helicopter's flight path. The helicopter performed normally after the event; however, the pilot elected to perform a precautionary landing to an open field. During the post-flight inspection, the crew determined that the left sliding cabin door had departed the aircraft. It was subsequently located separated into two pieces about 1 mile northeast of the landing site. One main rotor blade sustained substantial damage consistent with an in-flight impact with the door assembly. A postaccident examination did not reveal any anomalies consistent with a failure of the door assembly or airframe structure that would have led to the separation. The retaining angle remained attached to the door and appeared undeformed. The door latch pin had separated from the lanyard and was located lying on the aft cabin floor. The exact reason that the pin had separated from the lanyard before the accident flight could not be determined. The helicopter operating handbook permitted flight up to 120 knots with the door properly secured in the open position. In order toproperly secure the door, it must be in the full open position with the door latch pin installed. In the event that the door inadvertently opened in-flight, the airspeed should be reduced below 50 knots in order to allow the door to be closed. If the door could not be closed, then it must be fully opened and secured by the open door latch. ## Aircraft - Registration: [N72595](https://openairdocs.org/deregistered/N72595-2022-12-15), registration cancelled 2022-12-15, S/N 73-21769 (OpenAirDocs) - Reported make and model: BELL UH1H - Registry model: [Bell UH-1H](https://openairdocs.org/model/bell-uh-1h) (registry code 1181407) (OpenAirDocs) - Category: Helicopter - Serial number: 73-21769 - Year built: 1973 - Airframe hours: 5736 - Engines: Lycoming T53-L13-703 1438 horsepower turbo shaft - Damage: Substantial damage - Flight: Other work use, Public use - Operator: U. S. Customs and Border Protection - Registered owner: U. S. Departement of Homeland Security - Airworthiness certificate: None - Last inspection: Condition, June 27, 2014, 120 hours before - Departed: BKS, Falfurrias, TX - Destination: MFE, McAllen, TX - Equipment: Handheld GPS, Satellite tracking device ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 44; injuries: none; commercial, flight instructor; airplane ratings: multi-engine land, single-engine land; instrument ratings: helicopter, airplane; medical: class 2, with waivers/limitations; last flight review August 27, 2014; seat: right; restraint: 4-point; flight hours: 9,950 total, 406 in this make and model, 9,882 as pilot in command, 12 in the last 90 days, 8 in the last 30 days, 1 in the last 24 hours - Co-pilot; age 51; injuries: none; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review September 12, 2014; seat: left; restraint: 4-point; flight hours: 10,500 total, 1,851 in this make and model, 10,000 as pilot in command, 38 in the last 90 days, 14 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 360° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 84 °F, dew point 63 °F - Altimeter: 30.05 inHg - Observed at: EBG, 28 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). - [Incident 20141023021459I](https://openairdocs.org/incident/20141023021459I), Oct 23, 2014: Bell UH-1H, Rio Grande, TX, Minor damage. On oct. 23, 2014, a huey UH-1 helicopter lost its left cabin door in flight. According to james mills, air safety program manager for the office of air and… ## Docket (5 files) The files NTSB released with the investigation on December 1, 2014, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=90334. 3.9 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40419561&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Pilot Operating Handbook Excerpts (item 2, .PDF, 1.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40419562&FileExtension=.PDF&FileName=Pilot%20Operating%20Handbook%20Excerpts-Master.PDF - Diagram of Sliding Door (item 3, .PDF, 270 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40419563&FileExtension=.PDF&FileName=Diagram%20of%20Sliding%20Door-Master.PDF - Release of Aircraft Wreckage (item 4, .PDF, 146 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40419564&FileExtension=.PDF&FileName=Release%20of%20Aircraft%20Wreckage-Redacted.PDF - Statement of Party Representatives to NTSB Investigation (item 5, .PDF, 265 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40419565&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-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.