Passenger door opened during takeoff causing the flight crew to return and land.

Attributes
ACN	334357
Time
Date	199604
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : bos
State Reference	MA
Altitude	agl bound lower : 50 agl bound upper : 800
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : bos
Operator	general aviation : personal
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	climbout : takeoff climbout : initial
Flight Plan	VFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Person 1
Affiliation	Other
Function	instruction : instructor
Qualification	other other : other pilot : atp pilot : instrument pilot : commercial
Experience	flight time last 90 days : 40 flight time total : 2300 flight time type : 100
ASRS Report	334357
Person 2
Affiliation	Other
Function	instruction : trainee
Events
Anomaly	other anomaly other
Independent Detector	other flight crewa
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

Instrument student and instructor received clearance and taxi instructions for runway 22R. Taxi and runup was uneventful and performed when reaching runway hold short area, as #2 or #3 to go. Final check 'on and hold' without problem. We were alert to possible windshear from departing aircraft, cleared to go. We accelerated and rotated. At approximately 50 ft, instructor noticed sudden cabin change in noise and temperature, as main door had for unknown reason become unsecured by top latch. We controled aircraft, and prior to switch to departure requested a non priority return due to open door. Request was granted. Circled and returned uneventfully. Returned to FBO to examine cause. Note: aircraft had already flown 4.5 hours with 3 stops, with no identical problems. After reattempting 3 closures successfully back-to-back, no cause determined. Returned for takeoff and departed without incident. Only possible idea: fighting strong right xwinds at rotation, forcing instructor to lean significantly towards right. Perhaps this pressure on inside of door was too much for upper latch.

Original NASA ASRS Text

Title: PAX DOOR OPENED DURING TKOF CAUSING THE FLC TO RETURN AND LAND.

Narrative: INST STUDENT AND INSTRUCTOR RECEIVED CLRNC AND TAXI INSTRUCTIONS FOR RWY 22R. TAXI AND RUNUP WAS UNEVENTFUL AND PERFORMED WHEN REACHING RWY HOLD SHORT AREA, AS #2 OR #3 TO GO. FINAL CHK 'ON AND HOLD' WITHOUT PROB. WE WERE ALERT TO POSSIBLE WINDSHEAR FROM DEPARTING ACFT, CLRED TO GO. WE ACCELERATED AND ROTATED. AT APPROX 50 FT, INSTRUCTOR NOTICED SUDDEN CABIN CHANGE IN NOISE AND TEMP, AS MAIN DOOR HAD FOR UNKNOWN REASON BECOME UNSECURED BY TOP LATCH. WE CTLED ACFT, AND PRIOR TO SWITCH TO DEP REQUESTED A NON PRIORITY RETURN DUE TO OPEN DOOR. REQUEST WAS GRANTED. CIRCLED AND RETURNED UNEVENTFULLY. RETURNED TO FBO TO EXAMINE CAUSE. NOTE: ACFT HAD ALREADY FLOWN 4.5 HRS WITH 3 STOPS, WITH NO IDENTICAL PROBS. AFTER REATTEMPTING 3 CLOSURES SUCCESSFULLY BACK-TO-BACK, NO CAUSE DETERMINED. RETURNED FOR TKOF AND DEPARTED WITHOUT INCIDENT. ONLY POSSIBLE IDEA: FIGHTING STRONG R XWINDS AT ROTATION, FORCING INSTRUCTOR TO LEAN SIGNIFICANTLY TOWARDS R. PERHAPS THIS PRESSURE ON INSIDE OF DOOR WAS TOO MUCH FOR UPPER LATCH.

Data retrieved from NASA's ASRS site as of July 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.