NSIB Finds Invalid Cabin Crew Medical Certificate After Abuja Door Separation
The Nigerian Safety Investigation Bureau (NSIB) has identified an invalid cabin crew medical certificate among significant findings following the in-flight door separation involving a Bombardier Challenger 604 aircraft in Abuja. The revelation has prompted two immediate safety recommendations targeting Triton Aviation Limited and the Nigerian Civil Aviation Authority (NCAA). The findings raise fresh questions about crew compliance and regulatory oversight of operators holding permits for non-commercial flights.
The aircraft, registered as T7-SEI and operated by Triton Aviation Limited, lost its Passenger-Crew Door during initial climb from Nnamdi Azikiwe International Airport, Abuja, on October 15, 2026. The flight, designated DWC052, was scheduled to operate from Abuja to Murtala Muhammed International Airport, Lagos, with nine people aboard. They comprised two pilots, one cabin crew member and six passengers.
According to the preliminary report, the cabin crew member’s medical certificate was not valid when the occurrence happened. However, the two flight crew members were licensed and qualified to conduct the flight. The aircraft also held a valid Certificate of Airworthiness, Permit for Non-Commercial Flight (PNCF), Flight Operations Clearance Certificate and Maintenance Clearance Certificate. The latter two certificates were issued by the NCAA.
Door separation exposes critical safety concerns
The NSIB’s findings also reveal that the aircraft’s passenger-cabin door was already in an unlocked configuration when investigators examined its components. The door indicator displayed the UNLOCKED/RED legend, while both external and internal handles were found in the OPEN position. In addition, investigators found all the door locking mechanisms in the OPEN position. These findings are significant, although they do not independently establish how the door became unlocked.
The report further disclosed that the flight crew received no aural or visual warning indicating a door-related problem. Investigators also found no main door-related faults or warnings in the downloaded Maintenance Diagnostic Computer data. This raises important questions about the door warning system’s performance during the occurrence. However, the preliminary investigation has not established whether a technical malfunction contributed to the door separation.
The sequence of events began during the aircraft’s initial climb, when the captain observed an abnormal cabin altitude indication. Suspecting a pressurisation problem, the captain instructed the cabin crew member to double-check the main cabin door by pushing and pulling it. As the cabin crew member approached the Passenger-Crew Door, it opened and subsequently detached from the aircraft.
However, the cabin crew member told investigators that she did not touch the door before it opened. Some passengers also stated that they could not recall seeing her touch it. The report does not resolve this account against the physical evidence showing the door’s handles and locking mechanisms in their OPEN positions. Consequently, the precise circumstances surrounding the door’s opening remain under investigation.
Two immediate safety recommendations target operators and NCAA
Following the door separation, the NSIB issued Safety Recommendation A-2026-43 to Triton Aviation Limited. The recommendation requires the operator to ensure that every crew member assigned to its operations meets applicable regulatory requirements. These include licensing, qualification and competency requirements necessary for performing assigned safety and emergency duties. The invalid medical certificate identified during the investigation gives this recommendation particular significance.
The Bureau also issued Safety Recommendation A-2026-44 to the NCAA, calling for immediate enhancement of safety oversight of Permit for Non-Commercial Flight holders. The recommendation specifically addresses operators that elect to engage cabin crew members and assign them safety responsibilities. The regulator must ensure these operators employ appropriately qualified and licensed cabin crew personnel. This places the spotlight on oversight arrangements beyond conventional commercial airline operations.
The recommendations introduce a broader regulatory dimension to the door separation investigation. Although the aircraft held the required operational and maintenance clearances, the cabin crew medical certificate was not valid. The NSIB has therefore highlighted the need to ensure personnel assigned safety duties meet applicable requirements. However, the investigation has not established that the certificate irregularity contributed to the door detachment.
Aircraft returned safely despite substantial damage
Following the door separation, the captain declared an emergency and coordinated an immediate return with Abuja Air Traffic Control. The captain subsequently took over aircraft control, while the first officer assumed Pilot Monitoring duties. Meanwhile, the detached door struck the aircraft’s lower fuselage, damaging a VHF antenna. Investigators later recovered the door from a cornfield in Gui Village, Abuja Municipal Area Council, approximately five miles southwest of the airport.
During final approach, the first officer reportedly unfastened his seat belt and attempted to close the Passenger-Crew Door using the DOOR CLOSE button. The aircraft eventually landed safely on Runway 22 at approximately 17:34 local time. All nine occupants disembarked without injuries, although the aircraft sustained substantial damage. Aerodrome Rescue and Fire Fighting Services had also been alerted and remained on standby.
The NSIB emphasised that its preliminary report contains factual information and initial findings available at this stage. It does not provide an analysis or conclusions concerning the causes or contributing factors. The Bureau will publish its final report, including its conclusions and any additional safety recommendations, after completing the investigation.
The door separation incident therefore presents two distinct safety concerns requiring attention: the circumstances surrounding the door’s locking configuration and compliance with cabin crew qualification requirements. The NCAA’s response to the new recommendation will also be important, particularly regarding non-commercial operators assigning cabin crew safety responsibilities. The final investigation should establish how these issues relate to the occurrence, if at all, and identify any further measures needed to prevent a recurrence.
Source: Nigerian Safety Investigation Bureau (NSIB), Preliminary Report on T7-SEI, October 15, 2026.
