A HOME BUILT EXPERIMENTAL PUSHER ACFT IN CLB AT 3000 FT DECLARED AN EMER AND DIVERTED DUE TO SEVERE PROP VIBRATION CAUSED BY A COWLING INSPECTION DOOR DEPARTING THE ACFT STRIKING THE PROP.

Narrative

MY INTENTION WAS TO RIDE R SEAT AND FAMILIARIZE TEST PLT WITH ACFT; DO A HIGH SPD TAXI RUN; COME BACK TO HANGAR; REMOVE COWLING AND INSPECT ACFT. TEST PLT SAID SYS WERE NOT FAMILIAR TO HIM; SO DURING HIGH SPD TAXI RUN; HE KEPT THROTTLE IN AND EVEN AS WE LIFTED OFF I THOUGHT HE WAS GOING TO SET ACFT DOWN. WE WERE THEN COMMITTED; SO I ASSISTED WITH AIRSPD CALLOUTS AND RADIO WORK. I WAS NOT WELL PREPARED. A LOWER COWL INSPECTION DOOR CAME OFF (WE SURMISE) AND DAMAGED THE PROP. WE MADE AN EMER LNDG. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE ACFT WAS A HOME BUILT COMPOSITE PUSHER PWRED WITH A RECIPROCATING ENG. THE RPTR SAID THIS WAS THE FIRST PLANNED TEST SINCE CONSTRUCTION WAS COMPLETED AND WAS ONLY TO BE A HIGH SPD TAXI RUN. THE RPTR STATED THE AIRPLANE LIFTED OFF AT HIGH SPD AND AT 3000 FT A COWLING INSPECTION DOOR CAME OFF STRIKING THE PROP. THE RPTR SAID THE DOOR PUT SEVERAL DINGS IN 1 BLADE THAT CAUSED AN IMBAL AND RESULTANT SEVERE VIBRATION. THE RPTR SAID THE LNDG WAS UNEVENTFUL. THE RPTR STATED THE FAA HAS MADE NO CONTACT REGARDING THIS INCIDENT.