ANC05LA055

NTSB accident investigation · Britten-Norman BN-2A Islander · Klawock, AK · April 6, 2005

Accident · No injuriesLimited investigationFinal report
Date
April 6, 2005, 14:35 local (22:35 UTC)
Place
Klawock, AK
Injuries
3 uninjured
Damage
Substantial damage
Phase of flight
Landing
Aircraft
N29884Britten-Norman BN-2A Islander
Weather
Visual (VMC) · Day
Status
Completed · report January 31, 2006
Report
Approved by Office Director
NTSB office
Alaska Regional Office
Parties
Federal Aviation Administration
FAA report
20050406006419A
Case key
61279

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 fracture of the aluminum alloy landing gear bracket assembly, which resulted in a loss of control during the landing roll.

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/malfunctionLanding - roll
Landing gear,main gear - fracturedCause
Loss of control - on ground/waterLanding - roll
Directional control - not possiblePilot in command
On ground/water encounter with terrain/waterLanding - roll
Terrain condition - ditch

Analysis

The airline transport certificated pilot was landing a twin-engine airplane on a paved runway. The flight was conducted under Title 14, CFR Part 135, as a scheduled domestic passenger flight. The pilot reported that during the landing roll he noted a significant airframe vibration, and a pronounced rumbling noise as the airplane slowed. As he applied the brakes, the airplane veered to the left, and he was unable to keep the airplane on the runway. The airplane continued off the left side of the runway, and the nose of the airplane struck a drainage ditch. The airplane sustained substantial damage to the fuselage. During a postaccident inspection, maintenance personnel discovered a broken aluminum alloy landing gear oleo attachment bracket on the left main landing gear strut assembly. Operators that use the aluminum alloy landing gear oleo attachment brackets are required to conduct recurring inspections every 500 hours, or every 1,200 landings, which ever occurs first. According to the FAA airworthiness inspector that inspected the accident airplane's maintenance records, the aluminum alloy oleo attachment bracket was last inspected about 101.0 hours, and 218 landings before the accident. The FAA inspector commented that there was a substantial accumulation of dirt, grease, and oil on and around the broken oleo attachment bracket.

Factual narrative

On April 6, 2005, about 1435 Alaska daylight time, a twin-engine Britten-Norman BN-2A Islander airplane, N29884, sustained substantial damage following a main landing gear component failure and subsequent loss of control while landing at the Klawock Airport, Klawock, Alaska. The flight was conducted under Title 14, CFR Part 135, as a scheduled domestic passenger flight operated by LAB Flying Service, Haines, Alaska, as Flight 609. The airline transport certificated pilot and the two passengers were not injured. Visual meteorological conditions prevailed, and VFR company flight following procedures were in effect. The accident flight originated at the Ketchikan Airport, Ketchikan, Alaska, about 1400.

During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on April 7, the pilot reported that during the landing roll on runway 02, he noted a significant airframe vibration, and a pronounced rumbling noise as the airplane slowed. He said that as he applied the brakes, the airplane veered to the left, and he was unable to keep the airplane on the runway surface. The airplane continued off the left side of the runway, and the nose of the airplane struck a drainage ditch. The airplane sustained substantial damage to the fuselage.

During a postaccident inspection, maintenance personnel discovered a broken landing gear oleo attachment bracket on the left main landing gear strut assembly.

The accident airplane's broken landing gear oleo attachment bracket, part number NB-40-0075, is the subject of a repetitive inspection procedure outlined in the Federal Aviation Administrations (FAA) airworthiness directive (AD) 2002-02-11, which allows two methods of compliance; the part may be replaced or the bracket must be inspected more frequently. The manufacturer has changed the design of the oleo attachment bracket which is made of aluminum alloy. The newly designed oleo attachment bracket, part number NB-40-0479 is made of steel. Installation of the newly designed, steel oleo attachment bracket significantly reduces the number of repetitive inspections required. Operators that elect to utilize the old style aluminum alloy oleo attachment brackets are required to conduct recurring inspections every 500 hours, or every 1,200 landings, which ever occurs first.

According to an FAA airworthiness inspector from the Juneau Flight Standards District Office (FSDO), who inspected the accident airplane's maintenance records, the aluminum alloy oleo attachment brackets were last inspected about 101.0 hours, and 218 landings before the accident. The FAA inspector noted that there was a substantial accumulation of dirt, grease, and oil on and around the broken oleo attachment bracket. The FAA inspector said that during the last main landing gear overhaul, the operator elected to install the old style aluminum alloy oleo attachment brackets, primarily due to the cost of the new style steel oleo attachment brackets.

Aircraft

Registration
N29884
Reported as
Britten-Norman BN-2A Islander
Category
Airplane
Serial number
847
Airframe hours
9,145.9
Engine
Lycoming O-540-E4CS, 260 horsepower, reciprocating
Damage
Substantial damage
Flight
Part 135
Operator
L A B Flying Service Inc
Registered owner
L & A Bennett, Family Trust
Airworthiness certificate
Standard, Normal
Last inspection
AAIP · March 1, 2005 · 25.7 hours before
Departed
PAKT · Ketchikan, AK
Destination
PAKW · Klawock, AK
Flight plan
Company VFR
Airport
AKW · Klawock, runway 02, 5,000 × 100 ft, asphalt

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
54
Injuries
None
Certificate
Airline transport
Airplane ratings
Single-engine sea, Multi-engine land
Instrument ratings
Airplane
Medical
Class 1, With waivers/limitations
Seat
Left
Flight hours
13,000 total · 3,000 in this make and model · 12,600 as pilot in command · 150 in the last 90 days · 50 in the last 30 days · 3 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Visibility
10 statute miles
Lowest ceiling
5,000 ft broken
Temperature
52 °F, dew point 34 °F
Altimeter
29.75 inHg
Observed at
PAKW

FAA reports on this event · 1

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