20200826012909I

On 08/26/2020 at approximately 13:00 eastern standard time, N322CA, a Piper PA-28R-180, s/n 28R-7130013, landed gear up at pdk airport on runway 34. The flight was a local part 61 training flight for a CFI candidate. The instructor and student were practicing touch and go?s. no injuries were sustained and day, visual meteorological conditions prevailed with no wind according to kpdk metars data.

I was notified at 13:06 local time by the regional operations center. I arrived on scene at 15:10 local. I conducted an examination of the incident scene, took photographs, and interviewed the pilots. I released the aircraft for removal from the runway at approximately 16:00 local.

The incident scene showed the aircraft on its belly just left of the runway centerline. The nose landing gear was still down and locked. The left main landing gear was torn out from the trunnion area and resting on the runway under the trailing edge of the left wing, brake side down. The left MLG was still connected only by the brake line, down/locked switch wires were severed. The right MLG was collapsed and folded up into the wheel well. The aircraft came to rest leaning on the right wing with the left wing slightly off the ground. Flaps were up, MLG handle was down, mixture was lean, throttle was cracked, and propeller control was at low pitch (high RPM). The aircraft has a garmin glass panel installed, I powered up the garmin to record the flight hours.

I interviewed both pilots and they provided written statements.

Instructor?s statement reads:

?Doing touch and go practice with CFI candidate student. Landing was normal in nature and I could feel the plane bank left. I immediately figured it was the gear and added full power to take off again (we were on a touch and go). After climbing to a safe altitude, I saw a hole in the left wing. We did a low approach on 3L and staff from the school verified the left gear was twisted. We circled back to runway 34 and did a no flap landing.?

Student statement reads:

?My instructor and I were doing a local flight and we came in to land at pdk on 3L. We were on a stable approach and went to touch down and felt the left gear shake a little. We added full power and went around and had a unstable left gear light. We requested to land on 34 and told tower that we were probably going to have a gear collapse when we landed. We cut the mixture right before touchdown on 34 and also turned off the power. We landed down the runway and then the gear collapsed.?

I spoke with the A&P mechanic and asked him if the right MLG would have collapsed due to the left MLG damage and he said yes. He said it was due to the down and lock switches being only on the left MLG. There was also a concern of the left wing spar being bent but the mechanic has confirmed that the wing spar is not bent therefore it will remain an incident. He stated that the left forward MLG trunnion suffered a fatigue crack that caused the failure. I have confirmed that the landing gear AD 97-01-01 on MLG side braces had been complied with. These model aircraft have an alleged history of weak landing gear and the mechanic stated this particular aircraft has had several gear collapse landing events, yet no records of the events are in spas.

Of the nine responsibilities, I marked yes to airworthiness due to MLG trunnion failure. I marked aircraft part involved and recorded the part information. The owner has not yet made a decision as to rebuild or scrap the aircraft, no further action.