ANC99LA137

NTSB accident investigation · Stinson 108-2 · Chugiak, AK · September 9, 1999

Accident · No injuriesLimited investigationFinal report
Date
September 8, 1999, 16:30 local (Sep 9, 1999, 00:30 UTC)
Place
Chugiak, AK
Injuries
2 uninjured
Damage
Substantial damage
Phase of flight
Landing
Aircraft
N97978Stinson 108-2
Weather
Visual (VMC) · Day
Status
Completed · report November 22, 2000
Report
Approved by Office Director
NTSB office
Alaska Regional Office
FAA report
19990908025649A
Case key
47399

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

A partial failure of the brake system. A factor associated with the accident was a leaking brake system.

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.

Loss of control - on ground/waterLanding - roll
Landing gear,normal brake system - leakFactor
Landing gear,normal brake system - failure,partialCause
Ground loop/swerve

Analysis

The first pilot, a certificated flight instructor, was providing tailwheel transition flight instruction to the second pilot, a certificated private pilot. The first pilot said that eight successful stop and go landings had been accomplished prior to the accident landing. He said that while landing on runway 19 and during the landing roll, the second pilot applied the brakes. The airplane subsequently ground looped to the right, and the left wing struck the ground, resulting in substantial damage to the left wing. The first pilot said that brake pedals were only installed at the left side pilot position. After the accident, the second pilot related to the first pilot that during brake application, the left brake pedal 'felt mushy' and was less effective than the right brake. An FAA airworthiness inspector examined the airplane at the accident airport, and reported signs of brake fluid leaking from the left brake assembly. He added that disassembly of the left brake assembly revealed 'severely weathered and worn seals.'

Factual narrative

On September 8, 1999, about 1630 Alaska daylight time, a tailwheel equipped Stinson 108-2 airplane, N97978, received substantial damage while landing on runway 19 at the Birchwood Airport, Chugiak, Alaska. The first pilot, a certificated flight instructor, seated in the right seat, and the second pilot, a certificated private pilot, seated in the left seat, were not injured. The airplane was being operated as a visual flight rules (VFR) local area instructional flight under Title 14, CFR Part 91, when the accident occurred. Visual meteorological conditions prevailed, and no flight plan was filed.

During a telephone conversation with the NTSB investigator-in-charge on September 10, the first pilot reported that he was providing tailwheel transition flight instruction to the second pilot. He said that eight successful stop and go landings had been accomplished prior to the accident landing. He stated that while landing on runway 19 and during the landing roll, the second pilot applied the brakes. The airplane subsequently ground looped to the right, and the left wing struck the ground, resulting in substantial damage to the left wing. The first pilot reported that brake pedals were only installed at the left side pilot position.

After the accident, the second pilot related to the first pilot that during brake application, the left brake pedal "felt mushy" and was less effective than the right brake.

A Federal Aviation Administration (FAA) airworthiness inspector, Anchorage Flight Standards District Office, examined the airplane at the accident airport on September 10. He reported signs of brake fluid leaking from the left brake assembly. He added that disassembly of the left brake assembly revealed "severely weathered and worn seals."

Aircraft

Registration
N97978
Reported as
Stinson 108-2
Category
Airplane
Serial number
108-978
Engine
Lycoming O-435, 225 horsepower, reciprocating
Damage
Substantial damage
Flight
Instructional · Part 91
Registered owner
Scott C. Marcy
Airworthiness certificate
Standard, Normal
Last inspection
Annual · September 3, 1998 · 24 hours before
Departed
BCV · Birchwood, AK
Destination
BCV
Airport
BCV · Birchwood, runway 19, 4,010 × 100 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
61
Certificates
Flight instructor, Airline transport
Airplane ratings
Multi-engine land, Single-engine sea, Single-engine land
Instrument ratings
Airplane
Medical
Class 1, Valid Medical--w/ waivers/lim
Seat
Right
Flight hours
7,800 total · 13 in this make and model · 7,500 as pilot in command · 125 in the last 90 days · 41 in the last 30 days · 3 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
200° at 4 knots
Visibility
50 statute miles
Lowest ceiling
None
Temperature
45 °F

FAA reports on this event · 1

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

Other investigations on N97978 · 2

Matched to the same aircraft by N-number and date.