"My Dad, Pvt. Harry F. Fleming, 3rd Defence Battalion,  was a 27 year old private during the campaign (later in the War a Staff Sergeant), so because of his advanced age he earned the nick name of Pop.  He was very proud of that name and his role as a father figure to so many young  soldiers away from home for the first time.
I am very sure that this is a piece of that plane (Ki-46 Dinah).  Dad told me the following about the incident
-It took place in conjunction with the big naval shelling of Dugout Sunday (Oct. 25,1942).
- The Plane was a twin engine recon plane.

-He said that "I couldn't believe my eyes as the plane was making a very low and slow pass along the strip right in front of me and then we all opened up on it".

-He said that he had a perfect shot at it and that he could see the tracers from his water cooled 50 going into one of the engines.

-He told me that he was sure others hit it also, including probably the bigger AA guns at the end of the strip.

-He said that he heard later that "the Japanese must have thought they had driven us into the jungle and they came to check it out."

-He took this piece of sheet metal from it and his buddy was going to make him a letter opener, but he never got around to it. (An outline of a letter opener is scribe on one side of it.)

I am not sure where his antiaircraft machine gun position was at the time of the incident.  Most of the time he was along Fighter Strip 1, but he also manned positions along Henderson Field and during at least one of the land engagements he and his gun crew were use to help provide crossfire into the jungle. 

Chris Fleming

In the aftermath of the October 1942 battle for Henderson Field the Japanese were unsure whether the SENDAI Division had broken through and taken the airfield. A recon aircraft was despatched from Rabaul to see who held the airfield.

The pilot made the mistake of coming in low and found out who owned the airfield just before he was blown out of the sky. This incident is refered to in many accounts. Here is a piece of the aircraft in question, courtesy of Mr. Chris Fleming, and an account of his fathers part in the action.
Mitsubishi KI-46 "Dinah"