# NTSB LAX98LA230: Piper PA-18-150, N6248R, Hyampom, CA, July 12, 1998 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 12, 1998, 08:20 local (15:20 UTC) - Place: Hyampom, CA - Coordinates: 40.599376, -123.399398 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=40.5994&lon=-123.3994&mi=10 - Phase of flight: [Emergency descent](https://openairdocs.org/ntsb-phases/600) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report June 22, 2000 - Report: Approved by Office Director - NTSB case key (mKey): 43186 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX98LA230 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/43186/pdf - Page: https://openairdocs.org/ntsb/LAX98LA230 ## 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 In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(partial) - mech failure/malf, descent - emergency - throttle/power lever,linkage - disconnected (cause) - maintenance,annual inspection - inadequate, other maintenance personnel (cause) - Forced landing, emergency descent/landing - On ground/water encounter with terrain/water, landing - flare/touchdown - terrain condition - sand bar - terrain condition - water - unsuitable terrain or takeoff/landing/taxi area - encountered, pilot 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](https://openairdocs.org/aircraft/N6248R), registered now, S/N 188320 (OpenAirDocs) - Reported make and model: Piper PA-18-150 - Registry model: [Piper PA-18-150](https://openairdocs.org/model/piper-pa-18-150) (registry code 7101828) (OpenAirDocs) - Registry engine: [Lycoming 0-360-A1D](https://openairdocs.org/engine/lycoming-0-360-a1d) (registry code 41504, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 188320 - Airframe hours: 2486 - Engines: 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 ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 33; 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 (OpenAirDocs). - [Accident 19980712016519A](https://openairdocs.org/incident/19980712016519A), Jul 12, 1998: Piper PA18150, Hyampom, CA, Substantial damage. (.4) After takeoff, the airplane made a climbout over mountainous terrain. After clearing the terrain, the pilot reduced the power and descended into an open… ## Other investigations on N6248R (1) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB ANC11CA054](https://openairdocs.org/ntsb/ANC11CA054), Jun 23, 2011: Piper PA-18-150 (N6248R), Nikiski, AK, substantial damage. Probable cause: The pilot's improper use of brakes during landing. From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.