FTW98LA060

NTSB accident investigation · Piper PA-24-250 · Lubbock, TX · December 1, 1997

Accident · Minor injuriesLimited investigationFinal report
Date
November 30, 1997, 18:42 local (Dec 1, 1997, 00:42 UTC)
Place
Lubbock, TX
Injuries
2 minor
Damage
Substantial damage
Phase of flight
Approach
Aircraft
N6661PPiper PA-24-250
Weather
Visual (VMC) · Day
Status
Completed · report November 6, 1998
Report
Approved by Office Director
FAA report
19971130035869A
Case key
20492

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

The inadequate maintenance of the landing gear assembly by maintenance personnel resulting in a partial gear extension, and the pilot's misjudgment of a proper touchdown point to intentionally shut down the engine resulting in the airplane landing short of the runway. A factor was the soft terrain.

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.

Airframe/component/system failure/malfunctionApproach
Landing gear,normal retraction/extension assembly - binding(mechanical)Cause
Maintenance,annual inspection - inadequateOther maintenance personnelCause
Main gear collapsedEmergency descent/landing
Terrain condition - softFactor
Engine shutdown - intentionalPilot in command
Proper touchdown point - misjudgedPilot in commandCause

Analysis

During the initial takeoff departure climb, the gear would not retract and the pilot returned to the airport where a mechanic examined the gear, serviced the struts, and performed a retraction test (gear were extended and retracted 3 consecutive times). Subsequently, the flight departed on the cross country flight with a planned refueling stop. During the approach, the gear would not extend. The pilot maneuvered in the area and performed the emergency gear extension procedures; however, the gear would not go beyond 1/2 extension. During the final approach to the runway, the pilot shut down the engine and the airplane landed short of the runway. The FAA inspector and a mechanic found that the 'slide tubes on the main gear had accumulated a lot of dirt causing some binding on their normal operation. This binding consistently caused the gear electric motor circuit breaker to pop.' The gear could be extended manually by the FAA inspector and the mechanic. Flight time since the last annual inspection was 57 hours.

Factual narrative

On November 30, 1997, at 1842 central standard time, a Piper PA-24-250, N6661P, owned and operated by a private individual under Title 14 CFR Part 91, the gear collapsed while landing short of runway 35L at the Lubbock International Airport, Lubbock, Texas. The commercial pilot and the passenger received minor injuries, and the airplane sustained substantial damage. The airplane, operating on an IFR flight plan, encountered visual meteorological conditions prior to the accident. The flight departed San Antonio, Texas, at 1215.

During a personal interview, conducted by the investigator-in-charge, and on the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2), the pilot reported that during the initial climb from San Antonio, the gear would not retract. He returned to the airport where a mechanic examined the gear, serviced the struts, and performed a retraction test (gear was extended and retracted 3 consecutive times). Subsequently, the flight departed San Antonio for Colorado Springs, Colorado. En route the flight encountered headwinds and the pilot decided to make a refueling stop at Lubbock. During the approach at Lubbock, the landing gear would not extend. The pilot maneuvered in the area and performed the emergency gear extension procedures for 2 hours trying to get the gear extended; however, it would not go beyond 1/2 extension. During the final approach to runway 35L, the pilot shut down the engine to try to save the propeller. The airplane landed short of the runway in soft terrain.

The FAA inspector and a mechanic examined the airplane at Lubbock. Structural damage occurred to the firewall, engine mounts, and fuselage. The mechanic, a previous owner of a PA-24-250 airplane, has over 20 years of maintenance experience working on equivalent equipment. The mechanic found that the "slide tubes on both the main gear had accumulated a lot of dirt causing some binding on their normal operation. This binding consistently caused the gear electric motor circuit breaker to pop." The gear could be extended manually by the FAA inspector and the mechanic.

A review of the maintenance records by the FAA inspector revealed that the last annual inspection was completed on April 30, 1997. Flight time since the annual inspection was 57 hours.

Aircraft

Registration
N6661P
Reported as
Piper PA-24-250
Category
Airplane
Serial number
24-1784
Airframe hours
5,151
Engine
Lycoming O-540-A1C5, 250 horsepower, reciprocating
Damage
Substantial damage
Flight
Personal · Part 91
Registered owner
Robert L. Zimmerman
Airworthiness certificate
Standard, Normal
Last inspection
Annual · April 30, 1997 · 57 hours before
Departed
SAT · San Antonio, TX
Destination
LBB
Flight plan
IFR
Airport
LBB · Lubbock International, runway 35L, 11,500 × 150 ft, concrete

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
79
Certificate
Commercial
Airplane ratings
Single-engine land
Instrument ratings
Airplane
Medical
Class 2, Valid Medical--w/ waivers/lim
Seat
Left
Flight hours
3,865 total · 3,862 in this make and model · 3,830 as pilot in command · 50 in the last 90 days · 11 in the last 30 days · 4 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
20° at 5 knots
Visibility
10 statute miles
Lowest ceiling
None
Temperature
46 °F, dew point 43 °F
Altimeter
29.00 inHg
Observed at
LBB

FAA reports on this event · 1

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

Other investigations on N6661P · 1

Matched to the same aircraft by N-number and date.