MIA05LA093

The pilot/mechanic arrived at the Seminole Lake Gliderport to repair the engine following an uneventful precautionary landing the day before due to a bent exhaust pushrod of the No. 2 cylinder. He replaced the damaged No. 2 cylinder exhaust pushrod, pushrod housing, pushrod seals and lock tab. He reported visually inspecting the valve springs which did not appear to be damaged, but did not inspect the valve, nor did he remove the cylinder. Following the repairs, the engine was started and a full static run-up was performed with no discrepancies noted. The flight departed for Kissimmee Gateway Airport and shortly after takeoff, the engine started running rough though it was still producing power. He elected to return to the Seminole Lake Gliderport and after recognizing he was going to overshoot the runway with the engine not producing full power, elected to perform a 360-degree turn back onto final approach. During the turn, the aircraft impacted trees and came to rest in a swamp south of the south edge of runway 18. A pilot-rated witness observed the airplane on final approach and noted that as it descended to treetop level, or the height of the buildings, the airplane began to abruptly pitch up and down and was abruptly yawing. It appeared to the pilot-rated witness that some of the motions of the airplane did not coincide with the wind conditions that he observed. Postaccident examination of the engine by an FAA inspector revealed the replaced pushrod was damaged on both ends, with no obvious indication of a stuck valve. Additionally, the rotator type exhaust valve stem cap was missing from under the exhaust rocker arm of the No.2 cylinder. The exhaust valve and guide were within new limits in compliance with the Lycoming overhaul manual. There was no evidence of carbon inside the guide; however, there was swirl marks from reaming of the guide. Review of Lycoming Service Bulletin (SB) No. 388C revealed inspection procedures to be carried out at 400 hours or earlier, when valve sticking is suspected. The SB indicates that failure to comply with this provision could result in sticking valves, or broken exhaust valves which could result in engine failure. A section of the SB outlines the inspection procedure that uses a "GO/NO-GO" gage, and recommends moving the exhaust valve completely out of the guide to avoid interference when using the GO/NO-GO gage to check the guide for wear or carbon build up. The mechanic did not report using the GO/NO-GO gage. Additionally, the mechanic did not report using a local manufactured tool.

On April 15, 2005, about 1440 eastern daylight time, a Piper PA-28-161, N270FT, registered to M & A Aviation, Inc., leased to and operated by Orlando Flight Training, Inc., collided with trees while returning to land following a rough running engine shortly after takeoff from Seminole Lake Gliderport, Groveland, Florida. Visual meteorological conditions prevailed at the time and no flight plan was filed for the 14 CFR Part 91 maintenance ferry flight from Seminole Lake Gliderport, to Kissimmee Gateway Airport, Kissimmee Florida. The airplane was substantially damaged and the private-rated pilot, the sole occupant, was not injured. The flight originated about 7 minutes earlier from Seminole Lake Gliderport.

The pilot stated that he arrived at the Seminole Lake Gliderport to repair the engine, which resulted in an uneventful precautionary landing the day before. He replaced the damaged No. 2 cylinder exhaust pushrod, pushrod housing, pushrod seals and lock tab. He reported visually inspecting the valve springs which did not appear to be damaged, but did not inspect the valve. Following the repairs, the engine was started and a full static run-up was performed with no discrepancies noted. The flight departed for Kissimmee Gateway Airport and approximately 2 miles after takeoff, the engine started running rough though it was still producing power. He elected to return to the Seminole Lake Gliderport and after recognizing he was going to overshoot the runway with the engine not producing full power, elected to perform a 360 degree turn back onto final approach. During the turn, the aircraft impacted trees and came to rest in a swamp south of the south edge of runway 18.

A pilot-rated witness reported he was aware the airplane had made a precautionary landing the previous day due to a bent pushrod. The airplane remained overnight, and the following day he noticed someone working on the airplane. He recognized that the previously bent pushrod and pushrod housing tube had been replaced, and the mechanic was wiping the engine compartment. He inquired whether the mechanic would remove the cylinder and the response was that he would fly the airplane home, and "I am sure it will be OK." The witness departed the area, and observe the airplane on short final approach approximately 200 to 250 feet above treetop level. The airplane appeared to be in a normal landing configuration and was descending to a normal touchdown point on the runway. As the airplane descended to treetop level, or the height of the buildings, the airplane began to abruptly pitch up and down and was abruptly yawing. It appeared to the pilot-rated witness that some of the motions of the airplane did not coincide with the wind conditions that he observed. The airplane descended to approximately 75 feet above ground level (AGL), and at that time he heard engine power applied; the engine sounded like it was running "rough." He then observed the airplane pitch up and he perceived the pilot was performing a go-around. The airplane was observed to bank to left and climb to approximately 100 feet continuing in a left turn onto the downwind leg. The airplane began descending and the bank angle increased to approximately 30 degrees when the airplane flew behind a two-story building. He then heard the sound of impact, and numerous people responded to the crash site.

Postaccident examination of the engine by a Federal Aviation Administration (FAA) airworthiness inspector revealed that the rotator type exhaust valve stem cap was missing from under the exhaust rocker arm of the No.2 cylinder. Damage to both ends of the No. 2 cylinder exhaust valve pushrod was noted; no evidence of a stuck valve was noted. Further examination of the No.2 cylinder revealed that the exhaust valve and guide were within new limits in compliance with the Lycoming overhaul manual. There was no evidence of carbon inside the guide; however, there was swirl marks from reaming of the guide.

Review of Lycoming Service Bulletin (SB) No. 388C revealed inspection procedures to be carried out at 400 hours or earlier, when valve sticking is suspected. The SB indicates that failure to comply with this provision could result in sticking valves, or broken exhaust valves which could result in engine failure. Part 2 of the SB outlines the inspection procedure that uses a "GO/NO-GO" gage, and recommends moving the exhaust valve completely out of the guide to avoid interference when using the GO/NO-GO gage to check the guide for wear or carbon build up. The mechanic did not report using the GO/NO-GO gage. Additionally, the mechanic did not report using a local manufactured tool.