EASA Raises Concerns About Door Malfunction Risk on Boeing 757-200 Freighter Conversions
The European Union Aviation Safety Agency (EASA) has warned airlines of a door malfunction risk on Boeing 757-200 passenger to freighter conversions.
In a Safety Information Bulletin (SIB) issued on June 23, the EASA referenced an incident in February 2021 that is being investigated by the German Federal Bureau of Aircraft Accident Investigation.
“An occurrence was reported, where a Boeing 757-236 PCF aeroplane experienced a sudden in-flight full opening of its Main Cargo Door (MCD). This serious incident occurred during the initial climb of the aeroplane, and at a relatively low altitude, thus avoiding an explosive decompression,” said the EASA.
The involved MCD had been installed a few years before the event in accordance with EASA Supplemental Type Certificate (STC) 10015539.
The EASA STC was issued as validation of the original FAA STC ST01529SE, granted to Precision Conversions LLC.
EASA said a similar incident had occurred in 2014 on another 757-236 PCF aeroplane also modified with the same MCD installation.
The agency said possibilities are being looked at as a cause, including the possibility of the presence of air in the MCD self-contained hydraulic system, which may possibly have resulted in an
undetected out-of-sequence closing and locking of the door.
Another possibility is severe weather conditions and suspected ice contamination of MCD position sensors, which may also have contributed to not detecting the actual unlocked status of the door before take off.
The EASA has made five recommendations:
Verify that the design improvements described in Precision Conversions LLC SB 757-52-0006 and SB 757-52-0007 have been embodied on the aeroplane (either in service via the SBs, or in
production as a forward fit) and, if not, implement the changes at the first opportunity.
Verify that the condition of the MCD View Ports of the MCD still warrants a good viewing of the latch/lock mechanism position (e.g. glass condition, scratches), and restore as necessary.
Check if the features described in Precision Conversions LLC SB 757-52-0007 are still present and in good condition (e.g. mirrors, colour contrast paint on the tip of the lock-pin).
Include into the operator’s Aircraft Maintenance Program (AMP) a task for the periodic check of the condition of the features described in Precision Conversions LLC SB 757-52-0006 and SB
757-52-0007 (Note: Precision Conversion LLC Supplemental Maintenance Manual PC-0118-06 52-30-00, pages 701-705 contains information on cleaning the mirrors, the view port windows, and painting the lock-pin tips).
In cold weather conditions, snow or in case of expected freezing conditions: – Prior to door closure, perform a visual inspection of the MCD sill area for possible contamination by slush, snow or ice accretion; and before each departure, flight crew or trained cargo personnel should verify that the MCD is fully closed, latched and locked by visual inspection of marker indicators.