ANC13LA049

NTSB accident investigation · Maule M-6-235 · Big Lake, AK · May 19, 2013

Accident · No injuriesLimited investigationFinal report
Date
May 19, 2013, 11:30 local (19:30 UTC)
Place
Big Lake, AK
Injuries
1 uninjured
Damage
Substantial damage
Phase of flight
Landing
Aircraft
N56464Maule M-6-235
Defining event
Landing-flare/touchdown: Hard landing
Weather
Visual (VMC) · Day
Status
Completed · report December 11, 2013
Report
Approved by Office Director
NTSB office
Alaska Regional Office
Parties
Federal Aviation Administration
FAA report
20130519009649A
Case key
86967

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 pilot’s execution of a hard landing, which resulted in the overstress fracture of the right main axle housing and the subsequent nosedown.

Findings · 2

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.

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 was practicing stop-and-go landings on the gravel-covered runway. Upon touchdown, the right main gear separated at the axle housing, which pivoted the airplane to the right as the main landing gear leg dug into the runway. The airplane subsequently nosed down and came to rest on the propeller spinner and left wing. The airplane sustained substantial damage to the left wing and lift struts. A postaccident examination revealed that the right main landing gear axle separated at the axle housing and main landing gear leg attachment point. Visual and magnified optical examinations of the fractured surfaces revealed features consistent with a bending overstress fracture, indicating that the pilot most likely executed a hard landing, which resulted in the fracture of the right main axle housing and the subsequent nosedown.

Factual narrative

On May 19, 2013, about 1130 Alaska daylight time, a tundra-tire and tailwheel-equipped Maule M-6-235 airplane, N56464, sustained substantial damage while landing at the Goose Bay Airport, about 9 miles south of Big Lake, Alaska. The airplane was being operated by the pilot as a visual flight rules (VFR) personal flight under the provisions of Title 14, CFR Part 91, when the accident occurred. The airline transport pilot was not injured. Visual meteorological conditions prevailed and a VFR military flight plan had been filed. The flight departed Elmendorf Air Force Base about 0830. During a telephone conversation with the National Transportation Safety Board investigator-in-charge (NTSB) on May 19, the pilot stated that he was practicing stop-and-go landings on the gravel covered runway at the Goose Bay Airport. Upon touchdown, the right main gear separated at the axle housing, which pivoted the airplane to the right as the main landing gear leg dug into the gravel covered runway. The airplane subsequently nosed down, coming to rest on the propeller spinner and left wing. The airplane sustained substantial damage to the left wing and lift struts. The pilot noted that the airplane was equipped with 35-inch tundra tires. A postaccident examination, by the pilot, revealed the right main landing gear axle separated at the axle housing to main landing gear leg attach point. A Senior Safety Board Metallurgist reported that visual and magnified optical examination of the fractured surfaces revealed features consistent with a bending overstress fracture. (A synopsis of the NTSB Metallurgist's case review is included in the public docket for this accident.)

Aircraft

Registration
N56464
Reported as
Maule M-6-235
Category
Airplane
Serial number
7416C
Airframe hours
4,000
Engine
Lycoming IO-540, 235 horsepower, reciprocating
Damage
Substantial damage
Flight
Personal · Part 91
Operator
Vaught Timothy R
Registered owner
Vaught Timothy R
Airworthiness certificate
Standard, Normal
Last inspection
Annual · March 1, 2013
Departed
PAED · Anchorage, AK
Destination
PAED · Anchorage, AK
Flight plan
VFR
Airport
Z40 · Goose Bay, runway 08, 3,000 × 75 ft, gravel

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
40
Injuries
None
Certificates
Military, Commercial, Flight instructor, Airline transport
Airplane ratings
Multi-engine land
Instrument ratings
Helicopter, Airplane
Medical
Class 2, Without waivers/limitations
Seat
Left
Flight hours
4,100 total · 20 in this make and model

Weather

Conditions
Visual (VMC) · Day
Wind
320° at 6 knots
Visibility
10 statute miles
Temperature
41 °F, dew point 10 °F
Altimeter
30.46 inHg
Observed at
PAMR, 12 nm away

Docket · 5

The files NTSB released with the investigation on August 23, 2013, on NTSB’s docket system: statements, records, photos and specialists’ reports. 921 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.