DEN03LA017

NTSB accident investigation · Piper PA-28R-201 · Tooele, UT · November 20, 2002

Accident · No injuriesLimited investigationFinal report
Date
November 20, 2002, 16:00 local (23:00 UTC)
Place
Tooele, UT
Injuries
2 uninjured
Damage
Substantial damage
Phase of flight
Landing
Aircraft
N850FSPiper PA-28R-201
Weather
Visual (VMC) · Day
Status
Completed · report May 13, 2003
Report
Approved by Office Director
Parties
Salt Lake City Flight Standards District Office
FAA report
20021120031979A
Case key
56123

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

On this page

Probable cause

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.

Sequence of events

NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.

Gear retraction on groundLanding - roll
Lack of familiarity with aircraftDual studentFactor
Gear retraction - inadvertentDual studentCause
Supervision - inadequatePilot in command(cfi)Factor
Maintenance,adjustment - improperManufacturerFactor
Landing gear,normal retraction/extension assembly - incorrectFactor
On ground/water collision with objectLanding - roll
Object - taxiway light
Object - airport sign/marker

Analysis

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.

Factual narrative

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."

Aircraft

Registration
N850FS
Reported as
Piper PA-28R-201
Category
Airplane
Serial number
2844080
Airframe hours
194
Engine
Lycoming IO-360-C1C6, 200 horsepower, reciprocating
Damage
Substantial damage
Flight
Instructional · Part 91
Registered owner
Salt Lake Community College
Airworthiness certificate
Standard, Normal
Last inspection
100 hour · October 25, 2002 · 38 hours before
Departed
SLC · Salt Lake City, UT
Destination
SLC
Airport
TVY · Bolinder Field, runway 35, 6,100 × 100 ft, asphalt

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew · 2

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
29
Injuries
None
Certificates
Flight instructor, Commercial
Airplane ratings
Single-engine land, Multi-engine land
Instrument ratings
Airplane
Medical
Class 3, Invalid Medical for flight
Last flight review
April 10, 2002
Seat
Right
Flight hours
669 total · 65 in this make and model · 629 as pilot in command · 235 in the last 90 days · 61 in the last 30 days · 5 in the last 24 hours
Role
Student pilot
Age
19
Injuries
None
Certificate
Student
Medical
Class 1, Valid Medical--no waivers/lim.
Seat
Left
Flight hours
28 total · 1 in this make and model · 1 as pilot in command · 28 in the last 90 days · 5 in the last 30 days · 1 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
340° at 7 knots
Visibility
10 statute miles
Lowest ceiling
None
Temperature
48 °F, dew point 30 °F
Altimeter
30.52 inHg
Observed at
SLC, 20 nm away

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.