# NTSB WPR22LA064: Beech A36, N4370W, Tooele, UT, November 24, 2021

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Class 3 · Limited · Final report
- Date: November 24, 2021, 12:40 local (19:40 UTC)
- Place: Tooele, UT
- Coordinates: 40.316985, -112.28225 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=40.3170&lon=-112.2823&mi=10
- Phase of flight: [Unknown](https://openairdocs.org/ntsb-phases/990) (OpenAirDocs' grouping)
- Defining event: [Unknown: Unknown or undetermined](https://openairdocs.org/ntsb-events/000)
- Highest injury: No injuries
- Injuries: 4 uninjured
- Status: Completed
- Report: Approved by Office Director
- Investigation class: Class 3
- NTSB office: Western Pacific Region
- Parties: Federal Aviation Adminsitration
- NTSB case key (mKey): 104397
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR22LA064
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/104397/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=104397
- Page: https://openairdocs.org/ntsb/WPR22LA064

## Probable cause

The total loss of engine power for reasons that could not be determined based on available evidence.

## Findings

NTSB's coded findings; those marked are part of the probable cause.

- [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Beech A36, 23 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=1151604), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md)

## Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event best describes what happened.

- [Enroute-descent: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341); cases with it: [Beech A36, 56 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=1151604), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md)
- [Enroute-descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Beech A36, 47 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=1151604), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md)
- [Landing: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Beech A36, 78 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=1151604), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md)
- [Unknown: Unknown or undetermined](https://openairdocs.org/ntsb-events/000) (defining event); cases with it: [Beech A36, 11 cases](https://openairdocs.org/ntsb-events/000/sequence.md?model=1151604), [All aircraft, 1,703 cases](https://openairdocs.org/ntsb-events/000/sequence.md)

## Analysis

The pilot stated that he began a descent to pattern altitude at the destination airport. When he reduced the propeller speed to 2,200 rpm, a “slapping sort of knock began as well as a shimmy in the plane.” The pilot arrested the descent, observed that the oil temperature and oil pressure were normal, and looked outside the airplane to verify that the flight control surfaces had no issues. The pilot then noticed that the airspeed had decreased to 130 miles per hour and that the controls became “heavy and very mushy.” The pilot initiated a forced landing to a nearby road but abandoned that plan when he observed a vehicle traveling on the road. The pilot advanced the propeller and throttle levers full forward but received no response from the engine, and he noticed that the cylinder head temperature gauge had “dropped completely to the left.” The pilot maneuvered the airplane to avoid power lines and landed in an open desert area. During the landing, the airplane struck trees, impacted terrain, and came to rest at a nose-low attitude. Postaccident examination of the airframe and engine revealed no evidence of any pre-existing mechanical malfunction that would have precluded normal operation. Utilizing the reported fuel quantity at the time of departure and fuel burn rate for the reported power setting, it was determined that the pilot had an adequate amount of fuel for the intended flight. As a result, the reason for the total loss of engine power could not be determined.

## Factual narrative

On November 24, 2021, about 1240 mountain standard time, a Beech A36, N4370W, was substantially damaged when it was involved in an accident near Tooele Valley Airport (TVY), Tooele, Utah. The pilot and three passengers were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that the airplane departed from Safford, Arizona, with 80 gallons of fuel aboard. The pilot reported that, during cruise flight at 12,500 ft mean sea level (msl), he used a 65% power setting, consistent with the power setting in the Pilot Operating Handbook (POH) for that phase of flight. As the airplane neared Gunnison, Utah, which was about 85 miles south of TVY, he switched from the right fuel tank to the left fuel tank. Shortly afterward, the pilot initiated descents to 10,500 ft msl and then 8,500 ft msl while west of Provo, Utah. The pilot stated that he maintained a mixture setting of 50° rich of peak throughout the descent. As the airplane neared the Tooele Valley, he descended the airplane to 6,500 ft msl and maneuvered around a ridgeline. While descending to pattern altitude at the destination airport, the pilot reduced the propeller speed to 2,200 rpm, at which time a “slapping' sort of knock began, as well as a shimmy in the plane.” The pilot arrested the descent and observed that the oil temperature and oil pressure were normal. He then looked outside the airplane and verified that no control surface issues were occurring. Afterward, the pilot focused his attention on engine performance. The pilot stated that the airspeed had decreased to 130 miles per hour and that the controls became “heavy and very mushy.” The pilot initiated a forced landing to a nearby road, but he observed a vehicle that was traveling on the opposite direction of the road and decided not to land there. The pilot then advanced the propeller and throttle levers full forward but received no response from the engine. The pilot also noticed that the cylinder head temperature gauge had “dropped completely to the left of the gauge.” The pilot stated that he pitched the airplane upward to avoid power lines and landed in an open desert area. During the landing, the airplane struck multiple juniper trees before it impacted terrain and came to rest nose low, which resulted in substantial damage to the left wing. The airplane was equipped with two 40-gallon fuel tanks, of which, 74 gallons of fuel is usable. The POH indicated that at a 65% cruise power setting, fuel burn is between 10.0 and 13.3 gallons per hour. Postaccident examination of the airframe and engine revealed no evidence of any pre-existing mechanical malfunction that would have precluded normal operation of the engine.

## Aircraft

- Registration: [N4370W](https://openairdocs.org/aircraft/N4370W), registered now, S/N E-559, built 1974 (OpenAirDocs)
- Reported make and model: BEECH A36
- Registry model: [Beech A36](https://openairdocs.org/model/beech-a36) (registry code 1151604) (OpenAirDocs)
- Registry engine: [Continental IO-520 series](https://openairdocs.org/engine/continental-io-520-series) (registry code 17032, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: E-559
- Year built: 1974
- Airframe hours: 5334.73
- Engines: Continental Motors IO-520-BA(10) 285 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, January 11, 2021
- Departed: SAD, Safford, AZ
- Destination: Same as departure
- Equipment: Stall warning system

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 47; injuries: none; private; airplane ratings: single-engine land; medical: basicmed; last flight review December 2, 2016; seat: left; restraint: 3-point; flight hours: 207.8 total, 75.5 in this make and model, 145 as pilot in command, 12.9 in the last 90 days, 11.9 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 360° at 9 knots
- Visibility: 10 statute miles
- Temperature: 37 °F, dew point 27 °F
- Altimeter: 30.39 inHg
- Observed at: KTVY, 18 nm away
- METAR: METAR KTVY 241935Z AUTO 36009KT 10SM SCT035 03/M03 A3039 RMK AO2=

## 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 20211124019839A](https://openairdocs.org/incident/20211124019839A), Nov 24, 2021: Beech A36, Tooele, UT, Substantial damage. On November 24, 2021 at 0935 local, N4370W departed safford AZ (ksad) with an expected destination of rexburg-madison county airport (rxe) including a fuel…

## Docket (6 files)

The files NTSB released with the investigation on July 6, 2023, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=104397. 6.7 MB in all.

- Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 12 pages, 842 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15368783&FileExtension=pdf&FileName=6120%20minus%20basic%20med%20items_Redacted-Rel.pdf
- Record of conversation - pilot (item 2, PDF, 2 pages, 136 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15369213&FileExtension=pdf&FileName=Record%20of%20Conversation%20pilot-Rel.pdf
- Statement of party representatives to NTSB investigation (item 3, PDF, 1 page, 3.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15369223&FileExtension=pdf&FileName=party_Redacted-Rel.pdf
- NTSB airframe and engine examination summary (item 4, PDF, 5 pages, 107 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15382951&FileExtension=pdf&FileName=airframe%20and%20engine%20examination%20summary%20report-Rel.pdf
- Release of aircraft wreckage, NTSB form 6120.15 (item 5, PDF, 1 page, 152 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15368671&FileExtension=pdf&FileName=Signed%20wreckage_releasedocs_Redacted-Rel.pdf
- Photo array (item 6, PDF, 3 pages, 3 photos, 1.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15368793&FileExtension=pdf&FileName=Photo%20Array-Rel.pdf

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.

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