LAX98LA230

NTSB accident investigation · Piper PA-18-150 · Hyampom, CA · July 12, 1998

Accident · No injuriesLimited investigationFinal report
Date
July 12, 1998, 08:20 local (15:20 UTC)
Place
Hyampom, CA
Injuries
1 uninjured
Damage
Substantial damage
Phase of flight
Emergency descent
Aircraft
N6248RPiper PA-18-150
Weather
Visual (VMC) · Day
Status
Completed · report June 22, 2000
Report
Approved by Office Director
FAA report
19980712016519A
Case key
43186

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

Inadequate annual inspection that resulted in a partial loss of engine power due to a missing bolt, nut, and cotter pin from the throttle/carburetor assembly.

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 engine power(partial) - mech failure/malfDescent - emergency
Throttle/power lever,linkage - disconnectedCause
Maintenance,annual inspection - inadequateOther maintenance personnelCause
Forced landingEmergency descent/landing
On ground/water encounter with terrain/waterLanding - flare/touchdown
Terrain condition - sand bar
Terrain condition - water
Unsuitable terrain or takeoff/landing/taxi area - encounteredPilot in command

Analysis

After takeoff, the airplane made a climbout over mountainous terrain. After clearing the terrain, the pilot reduced the power and descended into an open valley. Approximately 1,800 feet above the ground level, he advanced the throttle, but did not receive an increase in engine power. The pilot declared an emergency and attempted to land on a narrow gravel bar next to a river. The main landing gear skimmed over the water and up onto the gravel bar edge. The left main gear sunk into the soft gravel at the waters edge and the aircraft came to rest inverted on the gravel bar. The pilot stated that an annual inspection had been performed 11 days prior to the accident, and the airplane had accumulated 3 flight hours since the inspection. He further reported that when he inspected the throttle cable assembly, following the accident, he noted that it had become detached from the carburetor throttle arm due to a missing bolt, nut, and cotter pin. The FAA was unable to verify that those components were missing as the pilot had repaired and ferried the aircraft to another location.

Factual narrative

On July 12, 1998, at 0820 hours Pacific daylight time, a Piper PA-18-150, N6248R, impacted terrain and came to rest inverted after experiencing a loss of engine power during cruise near Hyampom, California. The aircraft, operated by the pilot/owner under 14 CFR Par 91, sustained substantial damage. The private pilot was not injured. Visual meteorological conditions existed for the personal flight and no flight plan was filed. The flight originated at 0800.

The pilot reported that he had just taken off from the accident airport and made a climbout over mountainous terrain. After passing over the terrain, he reduced power, and was executing descending "S" turns into an open valley. At 1,800 feet above ground level, he engaged the throttle to increase power, but there was no corresponding power increase. The pilot declared an emergency and chose a narrow gravel bar next to a river. He stated that due to the short length of the landing area, he was attempting to touchdown at the waters edge and roll out on the gravel bar. The aircraft touched down approximately 30 feet short and the main landing gear skimmed over the water and up onto the gravel bar edge. The left main landing gear sunk into the soft gravel at the water's edge and the aircraft came to rest inverted on the intended landing area.

In an interview with a Federal Aviation Administration (FAA) inspector from the Sacramento, California, Flight Standards District Office, the pilot said he landed on a sand bar in a river. He reported that the right main landing gear touched down on a sand bar and the left main landing gear touched down in the water. The throttle cable came off of the carburetor throttle arm, and the bolt, nut, and cotter pin were missing from the throttle cable.

In the pilot's written report, an annual inspection had been performed on the airplane approximately 11 days prior to the accident and had flown for 3 hours.

The FAA was unable to verify that the bolt, nut, and cotter pin were missing from the throttle cable, as the pilot had already repaired and ferried the aircraft to another location. The FAA reported that the pilot did not have a ferry permit.

Aircraft

Registration
N6248R
Reported as
Piper PA-18-150
Category
Airplane
Serial number
188320
Airframe hours
2,486
Engine
Lycoming O-360-C2A, 180 horsepower, reciprocating
Damage
Substantial damage
Flight
Personal · Part 91
Registered owner
Paul Z. Arey
Airworthiness certificate
Standard, Utility; Standard, Normal
Last inspection
Annual · July 1, 1998 · 3 hours before
Departed
Q75

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
33
Certificate
Private
Airplane ratings
Single-engine land
Medical
Class 1, Valid Medical--w/ waivers/lim
Seat
Front
Flight hours
192 total · 192 in this make and model · 144 as pilot in command · 21 in the last 90 days · 6 in the last 30 days

Weather

Conditions
Visual (VMC) · Day
Wind
320° at 7 knots
Visibility
10 statute miles
Lowest ceiling
900 ft overcast
Temperature
57 °F, dew point 57 °F
Altimeter
30.00 inHg
Observed at
ACV, 40 nm away

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 N6248R · 1

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