The European Union Aviation Safety Agency (EASA) has alerted airlines to a potential door malfunction risk affecting Boeing 757-200 passenger-to-freighter conversions.
In a Safety Information Bulletin (SIB) issued on June 23, EASA referred to a serious incident in February 2021 currently under investigation by the German Federal Bureau of Aircraft Accident Investigation.
The incident involved a Boeing 757-236PCF aircraft experiencing an unexpected full opening of its Main Cargo Door (MCD) during initial climb at a low altitude, narrowly avoiding explosive decompression.
The MCD in question had been installed several years prior under EASA Supplemental Type Certificate (STC) 10015539, originally validated from FAA STC ST01529SE granted to Precision Conversions LLC.
EASA noted a similar incident in 2014 involving another 757-236 PCF aircraft equipped with the same MCD installation.
Investigations are exploring potential causes, including the presence of air in the MCD’s self-contained hydraulic system, possibly leading to an undetected out-of-sequence closing and locking of the door. Additionally, severe weather conditions and suspected ice contamination of MCD position sensors are being considered as factors contributing to the door’s unlocked status not being detected before takeoff.
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.
Sources: AirGuide Business airguide.info, bing.com, aircargonews.net, Rebecca Jeffrey
