LAX03LA085

NTSB accident investigation · Mooney M20D · Casa Grande, AZ · January 24, 2003

Accident · No injuriesLimited investigationFinal report
Date
January 24, 2003, 11:45 local (18:45 UTC)
Place
Casa Grande, AZ
Injuries
2 uninjured
Damage
Substantial damage
Phase of flight
Landing
Aircraft
N6639UMooney M20D
Weather
Visual (VMC) · Day
Status
Completed · report October 28, 2004
Report
Approved by Office Director
Parties
Federal Aviation Administration
FAA report
20030124001199A
Case key
56475

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

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Probable cause

Collapse of the landing gear during landing rollout, resulting from the pilot/mechanic's incorrect landing gear locking mechanism (linkage) adjustment.

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 collapsedLanding - roll
Maintenance,adjustment - incorrectOwner/pilot mechanicCause
Landing gear,gear locking mechanism - unlocked
On ground/water collision with objectLanding - roll
Object - runway light

Analysis

Following a normal touchdown and during the rollout, the airplane's main landing gear collapsed. Thereafter, as the airplane slid to a stop it veered off the runway and collided with a runway light. The pilot reported that during his approach for landing, he had verified that the landing gear was extended. He had confirmed its extension by observing the green gear down lights illuminate. The pilot had previously performed maintenance to the landing gear system. The airplane had been operated for 4.77 hours since receiving its last annual inspection. According to the pilot, the gear collapsed due to an adjustment problem, which prevented the over-center linkage from completely locking. The FAA indicated that the pilot, who holds an airframe and powerplant mechanic certificate, had performed the landing gear related maintenance.

Factual narrative

On January 24, 2003, about 1145 mountain standard time, a Mooney M20D, N6639U, experienced the collapse of its main landing gear during landing rollout on runway 05 at the Casa Grande Municipal Airport, Casa Grande, Arizona. The airplane was substantially damaged. Neither the private pilot, who operated the airplane, nor the passenger was injured. The airplane was being operated on a personal flight under the provisions of 14 CFR Part 91. Visual meteorological conditions prevailed. No flight plan had been filed for the local area flight that originated from Casa Grande about 1045.

The pilot reported that during his approach for landing, he had checked three times to confirm that the landing gear was extended and the green landing gear down lights were illuminated. Everything appeared satisfactory, and he made a normal landing. As the airplane decelerated on the runway, the main landing gear collapsed. Thereafter, as the airplane veered off the runway it collided with a runway light.

On February 7, 2003, the Federal Aviation Administration (FAA) coordinator reported that the airplane examination revealed substantial damage had resulted during the gear collapse/impact event. The pilot reported that he owns the accident airplane. The airplane had been operated for 4.77 hours since receiving its last annual inspection. The pilot holds an FAA airframe and powerplant mechanic certificate, and he indicated that the airplane had previously undergone maintenance to its landing gear.

According to the pilot, during the mishap the landing gear collapsed due to an adjustment problem, which prevented the over-center linkage from completely locking. The FAA indicated that the pilot/mechanic had performed the landing gear related maintenance.

Aircraft

Registration
N6639U
Reported as
Mooney M20D
Category
Airplane
Serial number
134
Airframe hours
2,834
Engine
Lycoming O-360-A1D, 180 horsepower, reciprocating
Damage
Substantial damage
Flight
Personal · Part 91
Registered owner
Jack H. Arend
Airworthiness certificate
Standard, Normal
Last inspection
Annual · June 12, 2002 · 5 hours before
Departed
CGZ · Casa Grande, AZ
Destination
CGZ · Casa Grande, AZ
Airport
CGZ · Casa Grande Municipal, runway 05, 5,200 × 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

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
64
Injuries
None
Certificate
Private
Airplane ratings
Single-engine land
Medical
Class 3, Valid Medical--w/ waivers/lim
Seat
Left
Flight hours
1,261 total · 235 in this make and model · 1,092 as pilot in command · 13 in the last 90 days · 5 in the last 30 days · 1 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
140° at 4 knots
Visibility
10 statute miles
Lowest ceiling
None
Temperature
66 °F, dew point 36 °F
Altimeter
30.04 inHg
Observed at
CGZ

Docket · 1

The files NTSB released with the investigation on August 25, 2004, on NTSB’s docket system: statements, records, photos and specialists’ reports. 299 KB in all.

FAA reports on this event · 1

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