FTW97LA334

NTSB accident investigation · Beech E90 · Albuquerque, NM · August 31, 1997

Accident · No injuriesLimited investigationFinal report
Date
August 31, 1997, 17:40 local (23:40 UTC)
Place
Albuquerque, NM
Injuries
3 uninjured
Damage
Substantial damage
Phase of flight
Landing
Aircraft
N16NMBeech E90
Weather
Visual (VMC) · Day
Status
Completed · report May 4, 1998
Report
Approved by Office Director
FAA report
19970831029039A
Case key
20333

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

Fatigue failure of the right main landing gear retraction/extension torque tube.

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.

Main gear collapsedLanding - roll
Landing gear,normal retraction/extension assembly - fatigueCause
Landing gear,normal retraction/extension assembly - failure,totalCause

Analysis

During initial climb following takeoff from Santa Rosa on a medical evacuation flight, with a patient and 2 flight nurses aboard, the right main landing gear failed to fully retract. Prior to landing at Albuquerque the right main landing gear did not lock in the down position. During landing roll, the right main landing gear collapsed. Examination of the landing gear provided evidence that the retraction/extension torque tube failed in fatigue.

Factual narrative

On August 31, 1997, at 1740 mountain daylight time, a Beech E-90, N16NM, operating as a lifeguard flight from Santa Rosa, New Mexico, to Albuquerque, New Mexico, collapsed the right main landing gear during landing roll at Albuquerque. The airline transport pilot, 2 flight nurses, and the patient were not injured and the aircraft sustained substantial damage. Visual meteorological conditions prevailed and an IFR flight plan was filed for this Title 14 CFR Part 135 medical flight which departed Santa Rosa, New Mexico, at 1634.

According to the pilot, when the landing gear was raised after departure, he heard a grinding noise emitting from under the cabin floor and noted that the "gear in transit" light in the landing gear handle remained illuminated. The pilot said he pulled the landing gear motor circuit breaker and the noise stopped. He then attempted to recycle the gear with negative results. When the landing gear was lowered on arrival at Albuquerque, an unsafe right main landing gear indication was present. The pilot secured the right engine, feathered the right propeller, and made a precautionary landing. During landing roll, the right main landing gear collapsed. As a result of the right main landing gear collapse, the right wing sustained buckling damage.

Examination of the right main landing gear by a FAA airworthiness inspector provided evidence of a failure of the torque tube assembly (part number 50-810240). No other deficiencies were noted during the examination. The part had a total of 5,616 cycles since factory overhaul and had been in service approximately 3.5 years. The part is required to be overhauled at 7,500 cycles or 5 years whichever occurs first. The affected part was removed and sent to the Board's Materials Laboratory. According to the laboratory analysis, the torque tube failed in fatigue. The origin of the fatigue could not be determined.

The aircraft has since been repaired and returned to service with no further difficulties noted.

Aircraft

Registration
N16NM
Reported as
Beech E90
Category
Airplane
Serial number
LW62
Airframe hours
9,965
Engine
P&W PT6A-28, 550 horsepower, turbo prop
Damage
Substantial damage
Flight
Part 135
Registered owner
Seven Bar Flying Service
Airworthiness certificate
Standard, Normal
Last inspection
AAIP · August 5, 1997 · 62 hours before
Departed
Q58 · Santa Rosa, NM
Destination
ABQ
Flight plan
IFR
Airport
ABQ · Albuquerque International, runway 21, 10,000 × 150 ft, concrete

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
48
Certificate
Airline transport
Airplane ratings
Multi-engine land, Single-engine land
Instrument ratings
Airplane
Medical
Class 1, Valid Medical--w/ waivers/lim
Seat
Left
Flight hours
12,050 total · 200 in this make and model · 10,640 as pilot in command · 74 in the last 90 days · 24 in the last 30 days · 2 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
230° at 7 knots
Visibility
10 statute miles
Lowest ceiling
9,000 ft broken
Temperature
84 °F, dew point 45 °F
Altimeter
30.00 inHg
Observed at
ABQ, 1 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.