ANC18LA067

NTSB accident investigation · Cessna U206 · Pedro Bay, AK · August 18, 2018

Accident · No injuriesLimited investigationFinal report
Date
August 18, 2018, 10:00 local (18:00 UTC)
Place
Pedro Bay, AK
Injuries
6 uninjured
Damage
Substantial damage
Phase of flight
Landing
Aircraft
N441GRCessna U206
Defining event
Landing-landing roll: Part(s) separation from AC
Weather
Visual (VMC) · Day
Status
Completed · report June 8, 2020
Report
Approved by Office Director
NTSB office
Alaska Regional Office
Parties
Federal Aviation Administration
FAA report
20180818018509A
Case key
98182

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 fatigue fracture of both main landing gear legs during the landing roll, which resulted in the collapse and separation of both main landing gear legs.

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.

Landing gear system: main landing gearAircraft › Aircraft systems · Fatigue/wear/corrosionCessna U206F: 2 casesAll aircraft: 241 casesProbable cause

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

According to the pilot, before landing on the tidal beach, he conducted two passes over the landing area to check for debris and determine wind direction. He stated that, after touchdown on the beach, the airplane felt like it had a flat tire and subsequently veered to the right. The airplane came to rest in a left-wing-low attitude on a tidal mudflat and sustained substantial damage to the left wing, left horizontal stabilizer, and left elevator. The pilot examined the airplane and noted that both main landing gear legs had separated just above the main axle attach point. A laboratory examination revealed that both main landing gear legs failed due to fatigue cracking.

Factual narrative

On August 18, 2018, about 1000 Alaska daylight time, a Cessna U206F airplane, N441GR, sustained substantial damage while landing at a remote unimproved tidal beach about 36 miles east of Pedro Bay, Alaska. The airplane was registered to AK Air Leasing, LLC and operated by K Bay Air, LLC as a visual flight rules (VFR) on-demand commercial flight under the provisions of 14 Code of Federal Regulations Part 135 when the accident occurred. The commercial pilot and five passengers were not injured. Visual meteorological conditions prevailed, and company flight following procedures were in effect. The flight departed Homer, Alaska, about 0900. According to the pilot, before landing on the tidal beach, he conducted two passes over the landing area to check for debris and determine wind direction. After a stable approach, the left main and uphill tire touched down first followed by the right main tire. The pilot stated that after touchdown, it "felt like" the airplane had a flat tire and it subsequently veered to the right and came to rest in a left wing low attitude on a tidal mudflat. The airplane sustained substantial damage to the left wing, left horizontal stabilizer and left elevator. An initial examination of the airplane, by the pilot, revealed that both main landing gear legs separated just above the main axle attach point. An examination by the National Transportation Safety Board (NTSB) Materials Laboratory revealed that both main landing gear legs exhibited chevron marks leading to a thumbnail region consistent with fatigue cracking. The NTSB Materials Laboratory examination report is in the public docket for this accident.

Aircraft

Registration
N441GR
Reported as
Cessna U206 (F)
Category
Airplane
Serial number
U20601801
Built
1972
Airframe hours
4,480
Engine
Continental IO-520-F, 300 horsepower, reciprocating
Damage
Substantial damage
Flight
Part 135
Operator
K Bay Air LLC
Registered owner
AK Air Leasing LLC
Airworthiness certificate
Standard, Normal
Last inspection
100 hour · August 10, 2018
Departed
PAHO · Homer, AK
Destination
Pedro Bay, AK
Flight plan
Company VFR
Equipment
Handheld GPS, Auto-pilot

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
39
Injuries
None
Certificate
Commercial
Airplane ratings
Single-engine land, Multi-engine land
Instrument ratings
Airplane
Medical
Class 2, Without waivers/limitations
Last flight review
July 29, 2018
Seat
Left
Restraint
3-point
Flight hours
4,400 total · 1,660 in this make and model · 4,300 as pilot in command · 204 in the last 90 days · 60 in the last 30 days · 2 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
Calm
Visibility
10 statute miles
Lowest ceiling
6,500 ft overcast
Temperature
54 °F, dew point 48 °F
Altimeter
30.29 inHg
Observed at
PAHO

Docket · 3

The files NTSB released with the investigation on April 24, 2020, on NTSB’s docket system: statements, records, photos and specialists’ reports. 3.9 MB 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.