2017 Boeing 737-600 cabin depressurization near Munich

Incident Overview and Flight Details On 14 May 2017, a Boeing 737-600 departed Prague Airport at 09:25 UTC on runway 24, bound for Djerba-Zarzis Airport in Tunisia. During climb in German airspace, the aircraft experienced a cabin pressure loss around 09:39 UTC while passing flight level 320. The passenger oxygen masks deployed automatically. ## Crew Actions and Emergency Descent Both pilots donned their oxygen masks and initiated an emergency descent to flight level 100. At 09:40:14 UTC, the crew informed Munich Radar of the emergency descent and received clearance at 09:40:17 UTC. The crew decided to divert to Munich Airport and prepared for an approach to runway 26L. After declaring ready at 09:55:37 UTC, the aircraft was cleared for the ILS approach to runway 26L at 09:55:41 UTC. ## Landing and Post-Incident Findings The aircraft landed safely on runway 26L at approximately 10:05 UTC and taxied to parking stand 196 under its own power. Medical services at Munich Airport reported no health complaints from passengers or crew. ## Technical Investigation The German Federal Bureau of Aircraft Accident Investigation (BFU) determined that the pressure loss was caused by a leaking valve in the transition area from the APU to the cabin, specifically a bulk seal on the keel beam of the APU bleed duct. A loose clamp was found in position 2, where it should have been over the bulk seal in position 1. An additional leak was identified in the L/H-Pack area. Both cabin pressure controllers stored the error 'High Cabin Air Leak Rate,' which requires a cabin pressure rate exceeding 2,000 SLFPM. After repairs, a final pressure test revealed another leak at the L/H-Pack. After shutting down the L/H-Pack, the cabin was found to be airtight, and the aircraft was released for a no-passenger flight to flight level 250 under the Minimum Equipment List (MEL).