LAX08LA060

NTSB accident investigation · Cessna 305-A · Mokuleia, HI · February 14, 2008

Accident · No injuriesLimited investigationFinal report
Date
February 14, 2008, 12:45 local (22:45 UTC)
Place
Mokuleia, HI
Injuries
1 uninjured
Damage
Substantial damage
Phase of flight
Landing
Aircraft
N473GFCessna 305-A
Defining event
Landing: Landing gear collapse
Weather
Visual (VMC) · Day
Status
Completed · report August 28, 2008
Report
Approved by Office Director
Parties
Federal Aviation Administration
Case key
67535

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 failure of the left main landing gear strut due to fatigue. Contributing to the failure was the side load placed on the landing gear while making a crosswind landing.

Findings · 4

NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.

Wind: crosswindEnvironmental issues › Conditions/weather/phenomena · Not specifiedCessna 305A: 6 casesAll aircraft: 1,008 casesProbable cause
Landing gear system: main gear strut/axle/truckAircraft › Aircraft systems · Fatigue/wear/corrosionCessna 305A: 1 caseAll aircraft: 86 casesProbable cause
Runway/land/takeoff/taxi surfaceEnvironmental issues › Physical environment · Not specifiedCessna 305A: 1 caseAll aircraft: 253 cases

Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.

Analysis

The pilot observed that the windsocks located at each end of runway indicated tailwinds of about 10 knots in either direction. The midfield sock indicated a direct crosswind from the north. The pilot elected to approach the east runway, and touched down abeam the midfield windsock. Upon touchdown the airplane encountered a left-to-right crosswind, and as the airplane decelerated, the pilot noticed the wind shift to a quartering right tailwind. He elected to abort the landing. As he advanced the throttle the engine sputtered, the left main gear collapsed, and the airplane ground looped as it approached the runway's edge. Examination of the left main landing gear spring strut revealed that the strut separated where the wheel bolts to the strut. The fracture face of the strut was granular in texture and uniform matte gray in color. The fracture surface for the section of landing gear strut that remained attached to the wheel was closely examined, and it was noted that the fracture surface had an approximate 1/16 inch flat dark triangular section at the corner of the mounting bolt hole. The Safety Board Materials Laboratory examination confirmed the presence of a 0.072 inch fatigue crack at this location that would be sufficient to cause a failure of the strut.

Factual narrative

On February 16, 2008, at 1245 Hawaiian standard time, a Cessna 305-A, N473GF, experienced a left main landing gear collapse during a crosswind landing at Dillingham Airfield, Mokuleia, Hawaii. The airplane was operated by the Honolulu Soaring Club under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The airline transport certificated pilot was not injured, and the airplane was substantially damaged. Visual meteorological conditions prevailed, and no flight plan had been filed. The local flight originated at Dillingham Airfield at 1230.

The pilot reported that he observed the windsocks at each end of runway 8/26, and both indicated tail winds of about 10 knots in either direction. The midfield windsock indicated a direct crosswind from the north. He elected to approach runway 8 and touched down abeam the midfield windsock. Upon touchdown the airplane experienced a left-to-right crosswind, and as the airplane decelerated, the pilot noticed the wind shift to a quartering right tail wind. He elected to execute a go-around. As he advanced the throttle, the engine sputtered, the left main landing gear collapsed, and the airplane ground looped to the left as it approached the runway's edge.

A Federal Aviation Administration inspector examined the left main landing gear spring strut and found that the strut separated where the wheel bolts to the strut. The fracture face of the strut was granular in texture and uniform matte gray in color. When the fracture surface of the landing gear strut section that remained attached to the wheel was more closely examined, it exhibited an approximate 1/16 inch flat dark triangular section at the corner of the mounting bolt hole. The Safety Board Materials Laboratory examination confirmed the presence of a 0.072 inch fatigue crack at this location.

Aircraft

Registration
N473GF
Reported as
Cessna 305-A
Category
Airplane
Serial number
2018
Airframe hours
10,000
Engine
Teledyne Continental Motors O-470, 230 horsepower, reciprocating
Damage
Substantial damage
Flight
Glider tow · Part 91
Operator
Honolulu Soaring Club
Registered owner
Honolulu Soaring Club
Airworthiness certificate
Standard, Utility
Departed
PHDH · Mokuleia, HI
Airport
PHDH · Dillingham Airfield, runway 8, 9,000 × 150 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
47
Injuries
None
Certificate
Airline transport
Airplane ratings
Single-engine land, Multi-engine land
Instrument ratings
Airplane
Medical
Class 1
Seat
Center
Flight hours
14,000 total · 6 in this make and model · 140 in the last 90 days

Weather

Conditions
Visual (VMC) · Day
Wind
190° at 5 knots
Visibility
10 statute miles
Lowest ceiling
3,000 ft overcast
Temperature
73 °F, dew point 64 °F
Altimeter
30.04 inHg
Observed at
PHHI, 12 nm away