Boeing 747-4B5F, HL-7601
HL-7601 was operating a commercial air transport (cargo) flight from Chicago O’Hare Airport to Brussels National Airport carrying 390 cows on the main deck. The aircraft was cruising at FL340 over the Irish Sea when the crew received a fire mn dk aft warning. A crew member went onto the main deck but saw no sign of smoke or fire. The crew suspected that the warning was false but decided to carry out the procedure in the Quick Reference Handbook for ‘Main Deck Cargo Compartment Suppression’, which involved donning oxygen masks and initiating a controlled cabin depressurisation and rapid descent. Following the descent, the crew made an uneventful landing at London Heathrow airport where emergency services attending the aircraft found no evidence of smoke or fire.
The pilot believed that the presence of the cattle led to higher than normal levels of humidity and that this was the cause of the warning.
Boeing 747-4B5F HL-7601 07-12.pdf (278.79 kb)