Challenger CL600
Flight Crew Flight Engineer; Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor; Flight Crew Multiengine; Flight Crew Instrument
Flight Crew Last 90 Days 50; Flight Crew Total 25000; Flight Crew Type 1100
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Other / Unknown
General Flight Cancelled / Delayed; General Maintenance Action
Aircraft; Procedure
During departure from ZZZ; the lavatory service door apparently opened inflight and departed the aircraft. During climb out; the crew noticed an 'Ext Door' light illuminated in the cockpit. Note that this light is not incorporated into the Master Caution Warning system. It is also located up underneath the cockpit glare shield and not readily visible to the cockpit crew during normal instrument scan. This light has historically been associated with the air pressure on the fuel service door switch causing light illumination and was assumed by the crew to be in this case. Upon post flight; the crew discovered that the lavatory service door was missing. Crew was not aware until this time that the door had been lost inflight. Loss was immediately reported to company.
CL60 Captain reported a service door open light illuminated in flight; later determined to be a lavatory service door; which had departed in flight.