EASA Warns of 757 Converted Freighter Door Malfunction
The European Union Aviation Safety Agency (EASA) is urging operators of certain Boeing 757s modified to freighters to ensure work in two service bulletins has been done and that crews verify the doors are firmly latched before departure to prevent them from opening in flight.
In a safety information bulletin (SIB) issued June 23, EASA cites two in-service incidents where main cargo doors have opened in flight. In the most recent one, involving a DHL 757 in February 2021, the main door opened during climb-out from Leipzig/Halle Airport in Germany. The crew declared an emergency and returned safely to the airport.
A preliminary report from Germany’s Federal Bureau of Aircraft Accident Investigation (BFU) found the hinges that connect the door to the fuselage were not locked prior to departure. The probe is focusing on two possible scenarios. A hydraulic system malfunction may have prevented the door from closing as designed.
Another possibility is ice contamination of sensors designed to tell the crew when the door is locked. A second, similar scenario, in Russian in 2014, occurred during severe winter weather, BFU noted. It did not provide further details on that occurrence or a related probe.
EASA’s bulletin, which applies to 757-200s converted from passenger to freighter under EASA Supplemental Type Certificate (STC) 10015539 issued in 2014, flags two service bulletins issued by STC holder Precision Conversions. One, issued in July 2006, explains a “collective locking system modification.” The other, issued October 2022, covers door indication system changes.
Affected operators should “verify that the design improvements described” in the SBs “have been embodied” on their aircraft and, if not, “implement the changes at the first opportunity.” EASA also said the view ports used to verify the latches are closed should be in good condition with no scratches or other major defects. Other aids, including a color-contrasted tip of a lock pin and mirrors to aid viewing of latches inside the closed door should also be in working condition.
BFU’s report does not detail any pre-flight activity related to closing the door. Following the occurrence, DHL issued safety actions for its 757-236 converted freighter fleet. Crews must check latches from the outside through the eight ports, and “attention must be paid to the latches being correctly locked and the locking pins being in their respective drill holes,” the safety action said. “The flight crews are advised to pay attention to the cargo door indications in the airplane. This should ensure that prior to the flight the cargo door is completely closed and locked.”