A B767-200's adp (air driven pump) access door departed sometime during flight.

Attributes
ACN	736761
Time
Date	200704
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : zzzz.airport
State Reference	FO
Altitude	agl single value : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : lft.tower
Operator	common carrier : air carrier
Make Model Name	B767-300 and 300 ER
Operating Under FAR Part	Part 121
Flight Phase	ground : parked
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	736761
Events
Anomaly	aircraft equipment problem : less severe
Independent Detector	other flight crewa
Resolutory Action	none taken : detected after the fact
Consequence	other other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

Exterior inspection of aircraft prior to flight was normal and daily check had been signed off by maintenance. I have no idea of why door exited the aircraft. Upon arrival in ZZZZ agent informed flight crew that a large piece of the aircraft was missing. Inspection showed that an access door aft of the left wing had torn off in flight and had dented fuselage. Maintenance personnel were flown in who performed necessary inspections and temporary repair. Appropriate ferry permit was obtained and we ferried the aircraft to ZZZ the next day. Callback conversation with reporter revealed the following information: the reporter stated that this aircraft had completed a major check several days before. During preflight the aircraft appeared normal. During post flight walk around the panel was found missing. The crew felt no abnormal flight characteristics during flight that would indicate when the panel departed. A slight amount of skin damage occurred when the door hit the fuselage as it left the aircraft.

Original NASA ASRS Text

Title: A B767-200'S ADP (AIR DRIVEN PUMP) ACCESS DOOR DEPARTED SOMETIME DURING FLT.

Narrative: EXTERIOR INSPECTION OF ACFT PRIOR TO FLT WAS NORMAL AND DAILY CHK HAD BEEN SIGNED OFF BY MAINT. I HAVE NO IDEA OF WHY DOOR EXITED THE ACFT. UPON ARR IN ZZZZ AGENT INFORMED FLT CREW THAT A LARGE PIECE OF THE ACFT WAS MISSING. INSPECTION SHOWED THAT AN ACCESS DOOR AFT OF THE L WING HAD TORN OFF IN FLT AND HAD DENTED FUSELAGE. MAINT PERSONNEL WERE FLOWN IN WHO PERFORMED NECESSARY INSPECTIONS AND TEMPORARY REPAIR. APPROPRIATE FERRY PERMIT WAS OBTAINED AND WE FERRIED THE ACFT TO ZZZ THE NEXT DAY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE REPORTER STATED THAT THIS ACFT HAD COMPLETED A MAJOR CHECK SEVERAL DAYS BEFORE. DURING PREFLT THE ACFT APPEARED NORMAL. DURING POST FLT WALK AROUND THE PANEL WAS FOUND MISSING. THE CREW FELT NO ABNORMAL FLT CHARACTERISTICS DURING FLT THAT WOULD INDICATE WHEN THE PANEL DEPARTED. A SLIGHT AMOUNT OF SKIN DAMAGE OCCURRED WHEN THE DOOR HIT THE FUSELAGE AS IT LEFT THE ACFT.

Data retrieved from NASA's ASRS site as of January 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.