Narrative:

I began my preflight in the dark; with very little sleep. I was preparing to takeoff to pick up passengers for [an early morning] flight. I completed a thorough preflight; however; I elected to leave the airplane plugged in to the tanis preheater for as long as possible before starting due to the cold temperature. I taxied out normally; ran up the airplane; and then departed normally. During cruise I occasionally noticed a slight unfamiliar vibration with the airplane but otherwise all was normal and smooth. I made my approach and was crossing the numbers when I heard a bang; saw debris fly away from the airplane; and the oil compartment door flip open. I made a normal landing and taxi in to the FBO. I advised the line service that there may be FOD on the runway and they began an inspection. I began my own inspection of the airplane and saw marks down the side of the nose where the oil door is locate; but internally the engine seemed fine. I restarted the engine and did a run-up to ensure that there was no damage to the engine and everything checked out normally. I shut down again and prepared to load up my passengers as the airport employee who inspected the runway returned. He returned with the chewed up extension cable used to connect the aircraft to the tanis preheater. It was then I realized I had flown the entire flight with the extension cord hanging from the nose of the airplane and was extremely fortunate it ended as well as it did.what I learned: fatigue played a large part in my oversight and may have clouded my judgment to not pull the plug as I initially addressed the plane during the preflight. The dark predawn conditions did not help as well; I likely would have noticed the cord still plugged in out of the corner of my eye before I got into the airplane had it been light outside. Another factor is that I was in a hurry to make my arrival time so I would be able to meet my passengers and depart on the second leg on time. The other issue was doing my preflight out of order; I did my standard walk around before I loaded my bags. By the time I was on the other side of the plane loading bags I had forgotten about the plug. Finally; the checklist I use does not include the use of the tanis preheater and checking of its condition. Going forward I am going to remove the plug first thing when I arrive at the plane during preflight and I am going to revise my checklist to include this item.

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Original NASA ASRS Text

Title: The pilot of a Diamond DA40 reported neglecting to remove the external heating unit extension cord prior to departure.

Narrative: I began my preflight in the dark; with very little sleep. I was preparing to takeoff to pick up passengers for [an early morning] flight. I completed a thorough preflight; however; I elected to leave the airplane plugged in to the Tanis preheater for as long as possible before starting due to the cold temperature. I taxied out normally; ran up the airplane; and then departed normally. During cruise I occasionally noticed a slight unfamiliar vibration with the airplane but otherwise all was normal and smooth. I made my approach and was crossing the numbers when I heard a bang; saw debris fly away from the airplane; and the oil compartment door flip open. I made a normal landing and taxi in to the FBO. I advised the line service that there may be FOD on the runway and they began an inspection. I began my own inspection of the airplane and saw marks down the side of the nose where the oil door is locate; but internally the engine seemed fine. I restarted the engine and did a run-up to ensure that there was no damage to the engine and everything checked out normally. I shut down again and prepared to load up my passengers as the airport employee who inspected the runway returned. He returned with the chewed up extension cable used to connect the aircraft to the Tanis preheater. It was then I realized I had flown the entire flight with the extension cord hanging from the nose of the airplane and was extremely fortunate it ended as well as it did.What I learned: Fatigue played a large part in my oversight and may have clouded my judgment to not pull the plug as I initially addressed the plane during the preflight. The dark predawn conditions did not help as well; I likely would have noticed the cord still plugged in out of the corner of my eye before I got into the airplane had it been light outside. Another factor is that I was in a hurry to make my arrival time so I would be able to meet my passengers and depart on the second leg on time. The other issue was doing my preflight out of order; I did my standard walk around before I loaded my bags. By the time I was on the other side of the plane loading bags I had forgotten about the plug. Finally; the checklist I use does not include the use of the Tanis preheater and checking of its condition. Going forward I am going to remove the plug first thing when I arrive at the plane during preflight and I am going to revise my checklist to include this item.

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.