Pc-12 pilot reported inadvertently knocking the flap handle out of the 15 degree detent just prior t...

Narrative:

I was taking off at ZZZ on an IFR flight to ZZZ1. After I completed my before takeoff check I was cleared for takeoff and began to taxi onto the runway. As I lined up for takeoff I switched from ground idle to flight idle. During this process it appears that I knocked the flaps out of takeoff position. I added power and during rotation I realized that the lift I needed for takeoff wasn't there. I immediately looked to the flap position and noticed it was out of the detent and half way between 15 degrees and 0 degrees. I knocked it back into 15 degrees but in the moment of confusion had let up on right rudder pressure. Meanwhile the plane turned slightly to the left as the plane built up speed. At this time I corrected with right rudder and slowly rotated and made a safe takeoff.in order to prevent this situation from occurring again I will put the plane into flight idle prior to completing my pre-take off check. This way there will be no way of me accidentally knocking the flap lever out of position. I will also double check that the flaps are in position as part of my flow prior to adding take off power.

Original NASA ASRS Text

Title: PC-12 pilot reported inadvertently knocking the flap handle out of the 15 degree detent just prior to departure; which resulted in an unsafe takeoff configuration.

Narrative: I was taking off at ZZZ on an IFR flight to ZZZ1. After I completed my before takeoff check I was cleared for takeoff and began to taxi onto the runway. As I lined up for takeoff I switched from ground idle to flight idle. During this process it appears that I knocked the flaps out of takeoff position. I added power and during rotation I realized that the lift I needed for takeoff wasn't there. I immediately looked to the flap position and noticed it was out of the detent and half way between 15 degrees and 0 degrees. I knocked it back into 15 degrees but in the moment of confusion had let up on right rudder pressure. Meanwhile the plane turned slightly to the left as the plane built up speed. At this time I corrected with right rudder and slowly rotated and made a safe takeoff.In order to prevent this situation from occurring again I will put the plane into flight idle prior to completing my pre-take off check. This way there will be no way of me accidentally knocking the flap lever out of position. I will also double check that the flaps are in position as part of my flow prior to adding take off power.

Data retrieved from NASA's ASRS site 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.

Attributes
ACN	1672862
Time
Date	201908
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	PC-12
Operating Under FAR Part	Part 135
Flight Phase	Takeoff
Route In Use	Direct
Flight Plan	IFR
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Flight Instructor Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 30 Flight Crew Total 5000 Flight Crew Type 16
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Other / Unknown

Pc-12 pilot reported inadvertently knocking the flap handle out of the 15 degree detent just prior to departure; which resulted in an unsafe takeoff configuration.