# NTSB WPR14LA242: Adams Dragonfly, N85TL, Mesa, AZ, June 12, 2014

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: June 12, 2014, 06:15 local (13:15 UTC)
- Place: Mesa, AZ
- Coordinates: 33.474998, -111.709724 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=33.4750&lon=-111.7097&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Defining event: [Initial climb: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report May 13, 2015
- Report: Approved by Office Director
- NTSB office: Western Pacific Region
- Parties: Federal Aviation Administration
- NTSB case key (mKey): 89423
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR14LA242
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/89423/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=89423
- Page: https://openairdocs.org/ntsb/WPR14LA242

## Probable cause

A partial loss of engine power due to a reduction in the No. 3 cylinder’s compression as a result of the exhaust valve not having consistent uniform contact with the cylinder head valve seat.

## 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: [Adams Thomas H DRAGONFLY, 1 case](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=05644LU), [All aircraft, 373 cases](https://openairdocs.org/ntsb-findings/01058530/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 (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Adams Thomas H DRAGONFLY, 1 case](https://openairdocs.org/ntsb-events/342/sequence.md?model=05644LU), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md)
- [Initial climb: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Adams Thomas H DRAGONFLY, 1 case](https://openairdocs.org/ntsb-events/440/sequence.md?model=05644LU), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md)
- [Landing-landing roll: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Adams Thomas H DRAGONFLY, 1 case](https://openairdocs.org/ntsb-events/470/sequence.md?model=05644LU), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md)

## Analysis

The pilot reported that, shortly after takeoff, the engine power decreased from about 3,100 to 2,500 rpm. The airplane continued to barely climb until it reached an altitude of about 150 ft above the ground. At that point, the airplane was unable to continue the climb or maintain altitude, and it began to descend. The pilot landed the airplane onto a field where it struck vegetation and came to rest in a bush about 1/2 mile from the departure end of the runway. During postaccident examination of the engine, the No. 3 cylinder had noticeably less compression, and a hissing noise was heard coming from the exhaust pipe. The cylinder was removed from the engine, and the piston head had a tan, sandy-colored appearance. Also, a light yellow band was observed around one-quarter of the circumference of the exhaust valve. Additional examination of the valve and valve seat revealed no defects; however, it did not appear that the exhaust valve was seated with consistent uniform contact; inconsistent uniform contact between the exhaust valve and the cylinder head valve seat would decrease engine performance.

## Factual narrative

On June 12, 2014, about 0615 mountain standard time, an experimental Adams Dragonfly, N85TL, experienced a partial loss of engine power after takeoff from Falcon Field Airport (FFZ), Mesa, Arizona. The private pilot was uninjured and the airplane sustained substantial damage to the left canard and elevator. The airplane was registered to, and operated by, the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed, and no flight plan was filed. The pilot reported that shortly after takeoff, the engine power decreased from 3,100 RPM to about 2,500 RPM. The airplane continued to barely climb until it reached an altitude of about 150 feet above the ground. At that point, the pilot was unable to continue the climb or maintain altitude, and the airplane began to descend. The pilot landed the airplane onto a field where it struck vegetation and came to rest in a bush about one-half mile from the departure end of the runway. During a postaccident examination by a Federal Aviation Administration inspector, the Volkswagen engine was rotated by hand. The inspector observed that there was noticeably less compression, along with a hissing noise coming from the engine's right side exhaust pipe. The right side valve cover was removed and it revealed that the number three cylinder was making the noise. The number three cylinder was removed and it was noted that the piston head had a tan, sandy colored, appearance. Also, a light yellow band was observed around one quarter of the circumference of the exhaust valve. Additional examination of the valve revealed no confirmed defects; however, there was no evidence that indicated the exhaust valve was seated with consistent uniform contact. The airplane's most recent maintenance was completed on February 1, 2013, about 11 flight hours prior to the accident. At that time, the cylinder heads were removed from the engine and replaced with stock Volkswagen cylinder heads, valves, rocker shafts, and valve covers. Since the maintenance occurred, the airplane flew three short flights and underwent various ground runs.

## Aircraft

- Registration: [N85TL](https://openairdocs.org/deregistered/N85TL-2014-08-12), registration cancelled 2014-08-12, S/N 1, built 1985 (OpenAirDocs)
- Reported make and model: ADAMS DRAGONFLY
- Registry model: [Adams Thomas H DRAGONFLY](https://openairdocs.org/model/adams-thomas-h-dragonfly) (registry code 05644LU) (OpenAirDocs)
- Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs)
- Category: Airplane, amateur-built
- Serial number: 001
- Year built: 1985
- Airframe hours: 132
- Engines: Volkswagen 2180 80 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Taigen Robert
- Registered owner: Taigen Robert
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: Continuous airworthiness, February 1, 2013, 11 hours before
- Departed: FFZ, Mesa, AZ
- Destination: FFZ, Mesa, AZ
- Airport: FFZ, Falcon Field Airport, runway 04R, 5,101 × 100 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 54; injuries: none; private; airplane ratings: single-engine land; medical: class 3, with waivers/limitations; last flight review March 8, 2014; seat: left; restraint: 3-point; flight hours: 741 total, 9 in this make and model, 741 as pilot in command, 23 in the last 90 days, 6 in the last 30 days, 0 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 360° at 5 knots
- Visibility: 40 statute miles
- Lowest ceiling: none
- Temperature: 81 °F, dew point 30 °F
- Altimeter: 29.87 inHg
- Observed at: FFZ

## 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 20140612008459A](https://openairdocs.org/incident/20140612008459A), Jun 12, 2014: Adams Thomas H DRAGONFLY, Mesa, AZ, Substantial damage. On 6/12/2014, at 0624 local time a 1985 Dragonfly aircraft departed Falcon Field ff on runway 4R. According to the pilot the engine rpms started to reduce just…

## Docket (4 files)

The files NTSB released with the investigation on April 16, 2015, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=89423. 1.1 MB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 838 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40425150&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF
- Record of Email - FAA Inspector's Examination Summary (item 2, .PDF, 72 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40425151&FileExtension=.PDF&FileName=Record%20of%20Email%20-%20FAA%20Inspector%27s%20Examination%20Summary-Master.PDF
- Maintenance Records - Most Recent Log (item 3, .PDF, 115 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40425152&FileExtension=.PDF&FileName=Maintenance%20Records%20-%20Most%20Recent%20Log-Redacted.PDF
- Release of Aircraft Wreckage, NTSB Form 6120.15 (item 4, .PDF, 61 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40425153&FileExtension=.PDF&FileName=Release%20of%20Aircraft%20Wreckage,%20NTSB%20Form%206120.15-Redacted.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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