NSIB Releases Preliminary Report On In-flight Door Separation Involving T7-Sei

The Nigerian Safety Investigation Bureau (NSIB) has released its Preliminary Report on the accident involving a Bombardier Challenger 604 aircraft, with nationality and registration marks T7-SEI, operated by Triton Aviation Limited, following the in-flight separation of its Passenger-Crew Door during initial climb after take-off from Nnamdi Azikiwe International Airport (DNAA), Abuja, on October 15, 2026.

A statement signed by Capt. Alex Badeh Jr. NSIB Director General / Chief Executive Officer says “the aircraft, operating as DWC052, was conducting a non-scheduled flight from Abuja to Murtala Muhammed International Airport, Lagos, with nine persons on board, comprising two flight crew members, one cabin crew member and six passengers.

At approximately 17:19 local time, during the initial climb, the flight crew observed an abnormal increase in cabin altitude and suspected a pressurisation issue. The captain subsequently instructed the cabin crew to double-check the main cabin door. As the cabin crew approached the Passenger-Crew Door to carry out the inspection, the door opened and subsequently detached from the aircraft.

The flight crew declared an emergency and coordinated with Abuja Air Traffic Control (ATC) for an immediate return to the airport. The aircraft landed safely on Runway 22 at approximately 17:34 local time. All nine occupants disembarked without injury. The aircraft sustained substantial damage.

Following notification of the occurrence on the same day, the NSIB immediately deployed investigators to the site to search for and recover the detached door, and commenced post-occurrence assessments. The detached door was subsequently recovered from a cornfield in Gui Village, Abuja Municipal Area Council, approximately five miles southwest of the airport.

The preliminary report is available for download on the NSIB website for members of the public and the media.

The Bureau reiterates that the preliminary report contains the factual information established during the investigation to date, including initial findings based on the evidence currently available and immediate safety recommendations arising from safety issues identified at this stage of the investigation. The report does not include analysis or conclusions regarding the causes or contributing factors associated with the occurrence, as the investigation remains ongoing. The bureau will publish its final report, including its analysis, conclusions, and further safety recommendations where appropriate, upon completion of the investigation in accordance with ICAO Annex 13 to the Convention on International Civil Aviation.”