"In a move to introduce new safety recommendations for detection of concealed fires in cargo containers the NTSB stated that "the early stages of a fire burning inside a cargo container are concealed from detection. In later stages, when the fire grows and does become detectable, it rapidly intensifies and burns through the container to become a substantial threat to the aircraft and crew""From:
http://www.avherald.com/h?article=459c8660&opt=0One of the incidents mentioned in the article was the crash of UPS B747-400 N571UP in Dubai. We discussed this incident in the thread below.
http://www.liveatc.net/forums/listener-forum/ups-747-cargo-plane-crashes-in-dubai/http://www.avherald.com/h?article=4307772e/0004&opt=0