Narrative:

I was scheduled to reposition an aircraft as soon as I arrived at work. I preflight the aircraft and taxied to the run-up area on the north ramp. Everything was normal at this point no abnormal indications. I began my run-up and after my prop cycling I checked the annunciator panel for anything and noticed the door warning light had come on. I brought the power back and checked the crew hatch. It did not extinguish the light. I decided to shut down the engines and check the rear door. I only pulled the mixtures at this point and climbed back quickly. I secured the upper door and the light went out. I climbed back into the seat secured my seat belt and did the before starting engine flow. I primed the left engine for a half of a second and engaged the starter. It was cranking and then I heard a backfire. I had heard a backfire before and felt it was normal enough to continue cranking. I then felt heat on my left leg and looked towards the front of the left engine and saw flames shooting out of the cowling and underneath. I immediately stopped cranking and pulled the mixtures back and evacuated the aircraft. I grabbed my phone which was handy on the way out then I called [operations center] as soon as I was a safe distance from the aircraft. I believe that I could have avoided this entire situation if I had just returned to the maintenance hangar when I noticed the door warning light. Also I believe I failed to perform the proper engine shut down procedures when I shut it down to check the rear door.

Google
 

Original NASA ASRS Text

Title: The pilot of a C402 was distracted by a door warning light during a ground based engine run-up. After shutting down the engine; the door was cycled to extinguish the light. The subsequent engine start attempt resulted in a fire inside the cowling.

Narrative: I was scheduled to reposition an aircraft as soon as I arrived at work. I preflight the aircraft and taxied to the run-up area on the north ramp. Everything was normal at this point no abnormal indications. I began my run-up and after my prop cycling I checked the annunciator panel for anything and noticed the door warning light had come on. I brought the power back and checked the crew hatch. It did not extinguish the light. I decided to shut down the engines and check the rear door. I only pulled the mixtures at this point and climbed back quickly. I secured the upper door and the light went out. I climbed back into the seat secured my seat belt and did the before starting engine flow. I primed the left engine for a half of a second and engaged the starter. It was cranking and then I heard a backfire. I had heard a backfire before and felt it was normal enough to continue cranking. I then felt heat on my left leg and looked towards the front of the left engine and saw flames shooting out of the cowling and underneath. I immediately stopped cranking and pulled the mixtures back and evacuated the aircraft. I grabbed my phone which was handy on the way out then I called [Operations Center] as soon as I was a safe distance from the aircraft. I believe that I could have avoided this entire situation if I had just returned to the Maintenance hangar when I noticed the door warning light. Also I believe I failed to perform the proper engine shut down procedures when I shut it down to check the rear door.

Data retrieved from NASA's ASRS site as of July 2013 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.