Service entry door unlatched just after departure.

Attributes
ACN	92645
Time
Date	198808
Day	Mon
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : bos
State Reference	MA
Altitude	msl bound lower : 300 msl bound upper : 300
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : bos
Operator	common carrier : air carrier
Make Model Name	Small Transport, Low Wing, 2 Turboprop Eng
Flight Phase	climbout : initial
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 300 flight time total : 7000 flight time type : 1200
ASRS Report	92645
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other flight crewa
Resolutory Action	other
Consequence	faa : reviewed incident with flight crew other other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

Shortly after takeoff, the pilot's auxiliary hatch of the small transport opened with the handle still in the locked position. This hatch is on the left side of the aircraft adjacent to the captain's seat. After climbing to a safe altitude, we assessed the damage and checked the condition of our 6 passengers. There were no injuries and I was unable to close the hatch. At first I thought that it left the aircraft, but later, after we landed, I noticed that it was still intact. It broke away from the restraining arm and moved to a position out of view when in-flight. Considering aircraft performance, poor communications due to wind noise, landing runway and traffic in the boston area, we decided to proceed straight ahead to manchester, nh. The aerodynamics were affected and I was reluctant to test another mode of flight other than straight and level. We were cleared for an approach to runway 35 in manchester and made a normal landing. All passengers were unhurt and there was only minor damage to the aircraft. My concern is the pilot's auxiliary hatch on the small transport. After talking to other capts at my airline, I was surprised to find that the same thing happened to many of them. Apparently, even with the handle in the locked position does not necessarily mean that the hatch is secure. I believe that it was a fault in the mechanism that caused the hatch to open in-flight.

Original NASA ASRS Text

Title: SERVICE ENTRY DOOR UNLATCHED JUST AFTER DEP.

Narrative: SHORTLY AFTER TKOF, THE PLT'S AUX HATCH OF THE SMT OPENED WITH THE HANDLE STILL IN THE LOCKED POS. THIS HATCH IS ON THE LEFT SIDE OF THE ACFT ADJACENT TO THE CAPT'S SEAT. AFTER CLBING TO A SAFE ALT, WE ASSESSED THE DAMAGE AND CHKED THE CONDITION OF OUR 6 PAXS. THERE WERE NO INJURIES AND I WAS UNABLE TO CLOSE THE HATCH. AT FIRST I THOUGHT THAT IT LEFT THE ACFT, BUT LATER, AFTER WE LANDED, I NOTICED THAT IT WAS STILL INTACT. IT BROKE AWAY FROM THE RESTRAINING ARM AND MOVED TO A POS OUT OF VIEW WHEN INFLT. CONSIDERING ACFT PERFORMANCE, POOR COMS DUE TO WIND NOISE, LNDG RWY AND TFC IN THE BOSTON AREA, WE DECIDED TO PROCEED STRAIGHT AHEAD TO MANCHESTER, NH. THE AERODYNAMICS WERE AFFECTED AND I WAS RELUCTANT TO TEST ANOTHER MODE OF FLT OTHER THAN STRAIGHT AND LEVEL. WE WERE CLRED FOR AN APCH TO RWY 35 IN MANCHESTER AND MADE A NORMAL LNDG. ALL PAXS WERE UNHURT AND THERE WAS ONLY MINOR DAMAGE TO THE ACFT. MY CONCERN IS THE PLT'S AUX HATCH ON THE SMT. AFTER TALKING TO OTHER CAPTS AT MY AIRLINE, I WAS SURPRISED TO FIND THAT THE SAME THING HAPPENED TO MANY OF THEM. APPARENTLY, EVEN WITH THE HANDLE IN THE LOCKED POS DOES NOT NECESSARILY MEAN THAT THE HATCH IS SECURE. I BELIEVE THAT IT WAS A FAULT IN THE MECHANISM THAT CAUSED THE HATCH TO OPEN INFLT.

Data retrieved from NASA's ASRS site as of August 2007 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.