# NTSB ERA10LA021: Palen AVRO-504K, N4929, Rhinebeck, NY, October 17, 2009

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: October 17, 2009, 15:05 local (19:05 UTC)
- Place: Rhinebeck, NY
- Coordinates: 41.969444, -73.85778 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=41.9694&lon=-73.8578&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Defining event: [Initial climb: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report July 22, 2010
- Report: Approved by Office Director
- NTSB office: Eastern Region Aviation
- Parties: FAA/FSDO
- NTSB case key (mKey): 74922
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA10LA021
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/74922/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=74922
- Page: https://openairdocs.org/ntsb/ERA10LA021

## Probable cause

A loss of engine power due to the in-flight separation of the number 3 cylinder valve rocker arm attachment hardware. Contributing to the accident was the improper maintenance inspection of the engine.

## Findings

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

- [Engine (reciprocating): recip eng cyl section](https://openairdocs.org/ntsb-findings/01058530): Aircraft › Aircraft power plant · Malfunction (probable cause); cases with it: [Palen AVRO-504K, 1 case](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=0562131), [All aircraft, 373 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md)
- [Maintenance: scheduled/routine maintenance](https://openairdocs.org/ntsb-findings/02062010): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Palen AVRO-504K, 1 case](https://openairdocs.org/ntsb-findings/02062010/cases.md?model=0562131), [All aircraft, 320 cases](https://openairdocs.org/ntsb-findings/02062010/cases.md)
- [Maintenance/inspections: scheduled maint checks](https://openairdocs.org/ntsb-findings/01010520): Aircraft › Aircraft handling/service · Inadequate inspection (probable cause); cases with it: [Palen AVRO-504K, 1 case](https://openairdocs.org/ntsb-findings/01010520/cases.md?model=0562131), [All aircraft, 76 cases](https://openairdocs.org/ntsb-findings/01010520/cases.md)

## Sequence of events

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

- [Initial climb: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Palen AVRO-504K, 1 case](https://openairdocs.org/ntsb-events/341/sequence.md?model=0562131), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md)
- [Approach-VFR pattern base: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Palen AVRO-504K, 1 case](https://openairdocs.org/ntsb-events/470/sequence.md?model=0562131), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md)

## Analysis

The pilot was performing an aerial demonstration for spectators. Shortly after takeoff, he heard a “thump,” the engine lost power, and he performed a forced landing in trees. Post-accident inspection of the wreckage revealed a keeper and cotter pin that connects the push rod to the number 3 cylinder valve rocker arm was missing. The high-tension spark plug lead to the number 5 cylinder was severed. The pilot, who also maintains the aircraft, believes the flailing spark plug lead flew into the commutator ring, shorting out other cylinders and leading to a total power loss. The missing hardware from the number 3 cylinder was never recovered. According to maintenance records, the airplane received a condition inspection on September 22, 2009. During that inspection, the number 5 cylinder was removed for repair and reinstalled, and the other rocker arms and valve springs were inspected.

## Factual narrative

On October 17, 2009, about 1505 eastern daylight time, an experimental Palen Avro-504K, N4929, was substantially damaged after a loss of engine power and forced landing near the Old Rhinebeck Airport (NY94), Rhinebeck, New York. The exhibition airplane was owned and operated by the Rhinebeck Aerodrome Museum. The commercial pilot was not injured. Visual meteorological conditions prevailed at the time, and no flight plan was filed for the 14 Code of Federal Regulations Part 91 air show flight. The flight was originating at the time of the accident. The pilot reported that approximately 200 feet above ground level after takeoff, a “thump” was heard from the engine. He did not have sufficient runway in front of him for landing, so he turned to the right, away from the spectator line. The engine was losing power, so he attempted to maintain flying speed and set up for a landing on the runway. While turning base leg for runway 10, the engine continued to lose power and the pilot was forced to set the airplane down in the trees. He estimated the airspeed to be 35 to 40 knots when the airplane contacted the trees. An inspector from the Federal Aviation Administration (FAA) inspected the airplane following the accident. The wings sustained structural damage from contact with the trees. Examination of the Le Rhone 9-cylinder radial engine revealed that a push/pull rod that operates the number 3 cylinder intake and exhaust valves was disconnected. A keeper and cotter pin that connects the push rod to the valve rocker arm was missing. The missing parts were not located after a search of the accident site. The pilot, who also maintained the airplane, reported that his inspection of the wreckage revealed a high-tension lead on the number 5 cylinder spark plug was severed, presumably from being struck by the hardware that liberated from the number 3 cylinder. He added that, the “high tension lead broke free of [the] spark plug and flew into [the] commutator ring, shorting out more cylinders causing the engine to fail completely.” According to maintenance records, the airplane received a condition inspection on September 22, 2009. During that inspection, the number 5 cylinder was removed for repair and reinstalled, and the other rocker arms and valve springs were inspected. The 1453 weather observation for Poughkeepsie, New York (POU), located 20 nautical miles south of the accident site, included the following: few clouds at 7,500 feet, surface winds from 360 degrees at 7 knots, 10 statute miles visibility, temperature 9 degrees Celsius, dew point 0 degrees Celsius, and an altimeter setting of 30.08 inches of mercury.

## Aircraft

- Registration: [N4929](https://openairdocs.org/aircraft/N4929), registered now, S/N HAC1, built 1966 (OpenAirDocs)
- Reported make and model: PALEN AVRO-504K
- Registry model: [Palen AVRO-504K](https://openairdocs.org/model/palen-avro-504k) (registry code 0562131) (OpenAirDocs)
- Registry engine: [Lerhone TYPE C](https://openairdocs.org/engine/lerhone-type-c) (registry code 40001, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: HAC1
- Airframe hours: 207
- Engines: LERHONE TYPE C 80 horsepower reciprocating
- Damage: Substantial damage
- Flight: Air race/show, Part 91
- Operator: Rhinebeck Aerodrome Museum
- Registered owner: Rhinebeck Aerodrome Museum
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: Condition, September 22, 2009, 6 hours before
- Departed: NY94, Rhinebeck, NY
- Destination: NY94, Rhinebeck, NY
- Airport: NY94, Old Rhinebeck Airport, runway 18, 2,200 × 75 ft, dirt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 50; injuries: none; commercial; airplane ratings: single-engine land, multi-engine land; medical: class 2, with waivers/limitations; last flight review February 22, 2007; seat: single; flight hours: 4,200 total, 20 in this make and model, 4,200 as pilot in command, 63 in the last 90 days, 30 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 360° at 7 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 48 °F, dew point 32 °F
- Altimeter: 30.07 inHg
- Observed at: POU, 20 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 20091017050339A](https://openairdocs.org/incident/20091017050339A), Oct 17, 2009: Palen AVRO-504K, Rhinebeck, NY, Substantial damage. Per the pilots statement, " on October 17, 2009 at 15:05, after running up the engine of the avro 504 k replica to 1250 rpms, I took off to the north and at…

## Other investigations on N4929 (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 NYC03LA119](https://openairdocs.org/ntsb/NYC03LA119), Jun 4, 2003: Palen Avro-504K (N4929), Rhinebeck, NY, substantial damage. Probable cause: A total loss of engine power during the initial climb for undetermined reasons.

## Docket (5 files)

The files NTSB released with the investigation on May 5, 2010, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=74922. 1.3 MB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 542 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323334&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF
- FAA Inspector's Statement (item 2, .PDF, 25 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323335&FileExtension=.PDF&FileName=FAA%20Inspector%27s%20Statement-Master.PDF
- Excerpts from Airframe and Engine Logbook (item 3, .PDF, 38 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323336&FileExtension=.PDF&FileName=Excerpts%20from%20Airframe%20and%20Engine%20Logbook-Redacted.PDF
- Photo 1 - Main Wreckage (FAA Digital Photo) (item 4, .PDF, 350 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323337&FileExtension=.PDF&FileName=Photo%201%20-%20Main%20Wreckage%20(FAA%20Digital%20Photo)-Master.PDF
- Photo 2 - Number 3 Cylinder Valve Rocker Arm Showing Missing Hardware (item 5, .PDF, 321 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323338&FileExtension=.PDF&FileName=Photo%202%20-%20Number%203%20Cylinder%20Valve%20Rocker%20Arm%20Showing%20Missing%20Hardware-Master.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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