Tooele, UT, USA
N850FS
Piper PA-28R-201
According to the instructor, the purpose of the flight was to prepare the student for dual cross-country flights and to familiarize him with the Piper PA-28R-201. Prior to this flight, the student pilot had been flying a Diamond Alarus, a training type airplane. They flew to a nearby airport, where they made three touch and go landings. On the fourth touch and go landing, the student pilot "assertively retracted the gear without warning" instead of the flaps. The right main and nose landing gear retracted and the airplane veered off the right side of the runway. The right wing struck a taxiway light, spinning the airplane around, and the left side of the fuselage struck a taxiway sign. The right wing was wrinkled and there was a gash from the leading edge back to the spar. The prop blade was bent. The left side of the fuselage was also wrinkled and buckled. According to FAA inspectors who examined the airplane, the squat switch on the landing gear had been rigged incorrectly. The squat switch actuated at .625 inches, exceeding the airplane's service manual requirement by .375 inches, or 150 percent. There were no entries in the maintenance records entries involving the squat switch. The torque seal on the squat switch mounting screws showed no signs of being disturbed.
On November 20, 2002, approximately 1600 mountain standard time, a Piper PA-28R-201, N850FS, registered to and operated by Salt Lake Community College, Salt Lake City, Utah, was substantially damaged when it collided with terrain after the landing gear retracted during touch and go landings at Bolinder Field-Tooele Valley Airport, Tooele, Utah. The commercial certificated flight instructor and student pilot were not injured. Visual meteorological conditions prevailed, and no flight plan had been filed for the instructional flight being conducted under Title 14 CFR Part 91. The local flight originated at Salt Lake City International Airport approximately 1445. According to the instructor, the purpose of the flight was to prepare the student for dual cross-country flights and to familiarize him with the Piper PA-28R-201. Prior to this flight, the student pilot had been flying Diamond Alarus, a training type airplane. After departing Salt Lake City International Airport, the airplane flew to a practice area west of Provo, Utah, then proceeded to Tooele, where three touch and go landings were made on runway 17. On the fourth touch and go landing, the student pilot "assertively retracted the gear without warning" instead of the flaps. The right main and nose landing gear retracted and the airplane veered off the right side of the runway. The right wing struck a taxiway light, spinning the airplane around, and the left side of the fuselage struck a taxiway sign. The right wing was wrinkled and there was a gash from the leading edge back to the spar. The prop blade was bent. The left side of the fuselage was also wrinkled and buckled. In his narrative, the instructor wrote, "An article I had read from 'Flight Training' magazine about 'instructor complacency' just 2 days before suddenly came up in the back of my mind. As it did, my right hand was ready at the controls within inches. I became very alert and felt I was ready for anything, even the 'unexpected', …or so I thought! Unfortunately, this is a case of human factors, and I should have been more attuned to that! The flap switch in the Alarus is an electric toggle, which does not look remotely close to the gear switch, but is very close to the same proximity. I believe that as my student relaxed and became more comfortable with the plane (after a few landings under his belt), he slipped into 'Alarus mode' and acted impulsively on what he's used to." Commenting on how the accident could have been prevented the instructor wrote, "Hindsight is painfully 20/20, but what I've adopted to my flight training/instruction is this: "Students (privates, commercial, instrument, etc.) Never touch the gear/flap switch without my confirmation: on takeoff, it's verbally, 'No more useable runway, positive rate, brakes tapped, gear up' (confirmation), then retract. Touch-and-goes, 'flaps up (confirmation), then retract, carb heat in, full power.' The callouts have always been the same, confirm, new. "No more touch-and-goes in complex [airplanes] with pilots new to the aircraft. "No more student pilots flying complex airplanes, unless very far along in training and have a thorough knowledge of human factors and we've discussed beforehand." Three FAA inspectors examined the airplane after it had been retrieved and transported to a storage facility. They found that the squat switch on the landing gear had been rigged incorrectly. The lead inspector wrote, "With the aircraft on jacks and weight off wheels, a measurement was taken between the top of the gear fork and the bottom of the gear housing of the Left Main Landing Gear (LMLG) strut at maximum extension. That dimension was measured and confirmed to be 8.125 inches. A multimeter was then attached to the contacts of the Squat Switch, and the Squat Switch contacts were confirmed closed (electrical continuity established). The strut was then compressed slowly until the contacts of the Squat Switch opened (switch actuated-electrical discontinuity). That process was accomplished twice, producing the same measurement of 7.5 inches between the top of the gear fork and the bottom of the gear housing as the point of switch actuation. "The Piper Arrow III -- Turbo Arrow III -- Arrow Service Manual, PA-28R-201/201T, Part Number 761-639, Paragraph 7-37 [ADJUSTEMENT OF LANDING GEAR SAFETY SWITCH (SQUAT SWITCH)], Paragraph c. states: 'Extend and then compress the strut to ascertain that the switch will actuate within the last quarter of an inch of oleo extension.' The results of our inspection placed the switch actuation at .625 inches, exceeding the Service Manual requirement by .375 inches or 150%. "Examination of the aircraft Airframe Log Book revealed no maintenance record entries involving the Squat Switch. The torque seal on the squat switch mounting screws showed no signs of being disturbed."
the inadvertent retraction of the landing gear during landing roll by the dual student. Contributing factors included the dual student's lack of familiarity with the aircraft, inadequate supervision by the flight instructor, and improper rigging of the landing gear squat switch.
Source: NTSB Aviation Accident Database
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