CEN12FA425

After extending the landing gear for his 5th practice landing, the pilot noted that the right main landing gear light only intermittently illuminated. After two pilots in other airplanes indicated that the accident airplane’s main landing gear appeared to be extended, the accident pilot decided to land without accomplishing emergency procedure checklist items. During the landing roll, the right main landing gear collapsed, and the airplane departed the right side of the runway. Postaccident examination revealed that the right main landing gear had not fully extended due to a combination of corrosion, inadequate lubrication, and a misadjusted gear-down limit switch. The misadjusted limit switch deactivated hydraulic pressure to the landing gear system before the gear could reach a down and locked condition, and the corrosion and lack of lubrication prevented full extension of the landing gear without the aid of hydraulic pressure.

HISTORY OF FLIGHT On July 5, 2012, about 1600 central daylight time, a Piper PA-28RT-201, N8308Y, was substantially damaged during landing at Mesquite Metro Airport (KHQZ), Mesquite, Texas. The pilot and one passenger sustained minor injuries. The personal flight was conducted by a private individual under the provisions of 14 Code of Federal Regulations Part 91 without a flight plan. Visual meteorological conditions prevailed during the flight. The local flight departed KHQZ at 1515. The pilot extended the landing gear while on downwind in preparation for his fifth landing that afternoon. He noted that the right main landing gear sensor did not appear to be functioning properly, as the light was “flickering” green. The pilot continued with this pattern and sought visual confirmation of landing gear position from another pilot flying behind his airplane on downwind, as well as from a pilot waiting for takeoff on the ground. Both these pilots radioed to the accident pilot that the airplane's landing gear appeared to be down. The pilot then made the decision to land the airplane without any further action. The pilot stated that his rationales for not attempting emergency procedures in the pilot operating handbook were his perception that the landing gear sensor was at fault and the visual confirmations of landing gear position he had received from the other two pilots. During the landing roll, the right main landing gear collapsed and the airplane departed the right side of runway. Substantial damage to the airplane included buckling of the left and right sections of the forward fuselage near the firewall, and the engine mounts were pushed aft through the firewall. PERSONNEL INFORMATION The pilot, age 46, held a private pilot certificate for airplane single-engine land issued February 26, 2012, and a third class airman medical certificate issued May 1, 2012, with no limitations. As of the accident, the pilot’s total flight time was 146 hours, pilot-in-command flight time was 94 hours, flight time in last 90 days was 23 hours, and flight time in make and model was 6.8 hours. AIRCRAFT INFORMATION The four seat, low-wing, retractable gear airplane, serial number 28R-8118039, was manufactured in 1981. Airplane records indicate that the last annual inspection occurred on January 20, 2012, with 9114 hours total time in service. The airplane was compliant with airworthiness directives and no inspections were due at the time of the accident. No recent landing gear maintenance was identified in the maintenance records. WRECKAGE AND IMPACT INFORMATION The airplane came to rest approximately 120 feet right of the runway 17 centerline in a sloped, grassy water drainage area with a 3- to 4-foot dropoff. Ground scarring on the runway tracked in a right arcing direction from near the runway centerline to the airplane. TESTS AND RESEARCH Examination of the airplane revealed evidence of corrosion and a lack of lubrication to the landing gear components. Duringtesting, the right main landing gear would not “freefall down.” Following lubrication of the right landing gear, the gear was able to “freefall down” into the down and locked position normally. According to the Piper maintenance manual, the gear down limit switch should be adjusted to allow it to actuate when the down lock hook has entered the locked position and is within 0.025 to 0.035 inch of contacting the down lock pin. At that point, the gear indicator light in the cockpit will illuminate. During examination, the gear down limit switch was found to have a gap measurement of 0.235 inches between the down lock hook and down lock pin. ADDITIONAL INFORMATION Section 3 Emergency Procedures of the PA-28RT pilot operating handbook contains an Emergency Landing Gear Extension checklist. Actions in this checklist include: “if landing gear has failed to lock down, yaw the airplane abruptly from side to side with the rudder” as well as “if landing gear does not check down, recycle gear through up position and then select gear down.”