F-406 caravan crew door was not properly latched and separated from aircraft during climbout.

Attributes
ACN	741025
Time
Date	200705
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	agl single value : 700
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air taxi
Make Model Name	Caravan II F406
Operating Under FAR Part	Part 135
Flight Phase	climbout : takeoff
Flight Plan	VFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : multi engine
Experience	flight time last 90 days : 30 flight time total : 11000 flight time type : 2000
ASRS Report	741025
Events
Anomaly	aircraft equipment problem : less severe
Resolutory Action	flight crew : landed as precaution
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

I was the PIC on a charter from ZZZ to ZZZ1. Shortly after departure of runway 24 and raising the landing gear a 'door warning' annunciator illuminated. Per the poh procedures I lowered the gear and kept the flaps down to reduce my airspeed and prepared to land back at ZZZ airport. I looked down at the crew door handle and noticed that it was coming out of the fully closed position and air was beginning to come through the bottom of the door. I felt that the door coming open was imminent and thought it would be safer to hold the door closed. As I was attempting to grab the handle enough air came through the bottom of the door to cause it open straight up and separate from the aircraft. I continued the left turn and landed on runway 6 in ZZZ without further incident and called the base. The aircraft was later ferried to ZZZ1 and then the next day to ZZZ2. I believe the handle on the crew door should have been double-checked to ensure that it was completely secure and never try to check the security of the door if you get the annunciator light.

Original NASA ASRS Text

Title: F-406 CARAVAN CREW DOOR WAS NOT PROPERLY LATCHED AND SEPARATED FROM ACFT DURING CLIMBOUT.

Narrative: I WAS THE PIC ON A CHARTER FROM ZZZ TO ZZZ1. SHORTLY AFTER DEP OF RWY 24 AND RAISING THE LNDG GEAR A 'DOOR WARNING' ANNUNCIATOR ILLUMINATED. PER THE POH PROCS I LOWERED THE GEAR AND KEPT THE FLAPS DOWN TO REDUCE MY AIRSPD AND PREPARED TO LAND BACK AT ZZZ ARPT. I LOOKED DOWN AT THE CREW DOOR HANDLE AND NOTICED THAT IT WAS COMING OUT OF THE FULLY CLOSED POS AND AIR WAS BEGINNING TO COME THROUGH THE BOTTOM OF THE DOOR. I FELT THAT THE DOOR COMING OPEN WAS IMMINENT AND THOUGHT IT WOULD BE SAFER TO HOLD THE DOOR CLOSED. AS I WAS ATTEMPTING TO GRAB THE HANDLE ENOUGH AIR CAME THROUGH THE BOTTOM OF THE DOOR TO CAUSE IT OPEN STRAIGHT UP AND SEPARATE FROM THE ACFT. I CONTINUED THE L TURN AND LANDED ON RWY 6 IN ZZZ WITHOUT FURTHER INCIDENT AND CALLED THE BASE. THE ACFT WAS LATER FERRIED TO ZZZ1 AND THEN THE NEXT DAY TO ZZZ2. I BELIEVE THE HANDLE ON THE CREW DOOR SHOULD HAVE BEEN DOUBLE-CHKED TO ENSURE THAT IT WAS COMPLETELY SECURE AND NEVER TRY TO CHK THE SECURITY OF THE DOOR IF YOU GET THE ANNUNCIATOR LIGHT.

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.