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20140612008459A

Accident · Substantial damage
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FAA accident report · Adams Thomas H DRAGONFLY · Mesa, AZ · June 12, 2014

FAA Aviation Safety Information Portal

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Date
June 12, 2014 · 06:24 local
Place
Mesa, AZ
Airport
Falcon Field
Phase of flight
Takeoff: Climb Out
Operating rules
General operating rules (Part 91)
Damage
Substantial damage
Aircraft
N85TL
NTSB investigation
NTSBWPR14LA242
Reported as
Adams Thomas H Dragonfly
Reported engine
Amateur-built VOLKWAGON
People aboard
1
Fatal injuries
0
Other injuries
0
Pilot’s certificate
Private pilot
Pilot’s flight hours
741 total23 in the last 90 days
N85TLRegistration cancelled Aug 12, 2014 · Adams Thomas H DRAGONFLYS/N 1 · Built 1985Airframe modelAdams Thomas H DRAGONFLYEngine modelAmateur-built UNKNOWN ENG

From the FAA’s Accident/Incident Data System (AIDS), through its Aviation Safety Information Portal, as reported. The NTSB investigates accidents separately, and its record of an accident is the fuller one. The aircraft is matched to the registry by N-number and event date, checked against the reported make and model; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

What happened

The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.

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 after takeoff to about 2500 rpms. The volkwagon engine in this aircraft produces full power @ 3100 RPM and significantly less at 2500 RPM. Then aircraft quit climbing and then began the porpoise'ing associated with the forward canard stalling and recovering without the main wing stalling. The aircraft impacted the ground about one-half mile from the departure end of runway 4R. The main landing gear was bent back submitting the spar attachment to higher than design loads. The forward left canard hit the ground at its tip and at the accident scene the left main wheel was observed to be forcing the elevator up beyond it normal range and wheel was against the lower surface of the canard. The canard was damaged at the juncture to the fuselage and the fuselage was deformed where the canard attaches.

Turning the engine over with the spark plugs in there was noticeably less compression on one of the cylinders and when the lower compression cylinder hand cranked through the compression stroke hissing noise was heard seemingly from the right had cylinders which was confirmed by listening at the right hand exhaust pipe. Cranking the engine over with the right valve cover off it was determined that the #3 cylinder was the one with lower compression and associated with the noise. Pulling the #3 cylinder revealed just the slightest color difference on the pistons with #3 more of a sandy colored and there was just a slight light yellowish band on the edge of the exhaust valve for about ¼ of its circumference.

The fuel system was dissembled from the selector valve through the throttle body looking for and defect that could have caused a lean mixture. The fuel was sampled at the main tank drain, the gascolator, and the header tank was drained. No abnormalities were found with the fuel.

Inspection of the valve and the valve seat did not confirm any defect but did not evidence a consistent uniform appearance of the contact surface. The engine had been run about 5 hours since the heads had been replaced. Much of that time was ground running. The aircraft had made 3 short flights since the head had been changed.

As the FAA filed it

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 AFTER TAKEOFF TO ABOUT 2500 RPMS. THE VOLKWAGON ENGINE IN THIS AIRCRAFT PRODUCES FULL POWER @ 3100 RPM AND SIGNIFICANTLY LESS AT 2500 RPM. THEN AIRCRAFT QUIT CLIMBING AND THEN BEGAN THE PORPOISE'ING ASSOCIATED WITH THE FORWARD CANARD STALLING AND RECOVERING WITHOUT THE MAIN WING STALLING. THE AIRCRAFT IMPACTED THE GROUND ABOUT ONE-HALF MILE FROM THE DEPARTURE END OF RUNWAY 4R. THE MAIN LANDING GEAR WAS BENT BACK SUBMITTING THE SPAR ATTACHMENT TO HIGHER THAN DESIGN LOADS. THE FORWARD LEFT CANARD HIT THE GROUND AT ITS TIP AND AT THE ACCIDENT SCENE THE LEFT MAIN WHEEL WAS OBSERVED TO BE FORCING THE ELEVATOR UP BEYOND IT NORMAL RANGE AND WHEEL WAS AGAINST THE LOWER SURFACE OF THE CANARD. THE CANARD WAS DAMAGED AT THE JUNCTURE TO THE FUSELAGE AND THE FUSELAGE WAS DEFORMED WHERE THE CANARD ATTACHES.

TURNING THE ENGINE OVER WITH THE SPARK PLUGS IN THERE WAS NOTICEABLY LESS COMPRESSION ON ONE OF THE CYLINDERS AND WHEN THE LOWER COMPRESSION CYLINDER HAND CRANKED THROUGH THE COMPRESSION STROKE HISSING NOISE WAS HEARD SEEMINGLY FROM THE RIGHT HAD CYLINDERS WHICH WAS CONFIRMED BY LISTENING AT THE RIGHT HAND EXHAUST PIPE. CRANKING THE ENGINE OVER WITH THE RIGHT VALVE COVER OFF IT WAS DETERMINED THAT THE #3 CYLINDER WAS THE ONE WITH LOWER COMPRESSION AND ASSOCIATED WITH THE NOISE. PULLING THE #3 CYLINDER REVEALED JUST THE SLIGHTEST COLOR DIFFERENCE ON THE PISTONS WITH #3 MORE OF A SANDY COLORED AND THERE WAS JUST A SLIGHT LIGHT YELLOWISH BAND ON THE EDGE OF THE EXHAUST VALVE FOR ABOUT ¼ OF ITS CIRCUMFERENCE.

THE FUEL SYSTEM WAS DISSEMBLED FROM THE SELECTOR VALVE THROUGH THE THROTTLE BODY LOOKING FOR AND DEFECT THAT COULD HAVE CAUSED A LEAN MIXTURE. THE FUEL WAS SAMPLED AT THE MAIN TANK DRAIN, THE GASCOLATOR, AND THE HEADER TANK WAS DRAINED. NO ABNORMALITIES WERE FOUND WITH THE FUEL.

INSPECTION OF THE VALVE AND THE VALVE SEAT DID NOT CONFIRM ANY DEFECT BUT DID NOT EVIDENCE A CONSISTENT UNIFORM APPEARANCE OF THE CONTACT SURFACE. THE ENGINE HAD BEEN RUN ABOUT 5 HOURS SINCE THE HEADS HAD BEEN REPLACED. MUCH OF THAT TIME WAS GROUND RUNNING. THE AIRCRAFT HAD MADE 3 SHORT FLIGHTS SINCE THE HEAD HAD BEEN CHANGED.

NTSB investigation

The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.

NTSB WPR14LA242Accident · No injuriesLimited investigationFinal reportMesa, AZA 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.Jun 12, 2014 · Substantial damage

Other reports on N85TL · 1

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

Incident 19880507024569IFcd/Prec Ldg From Cruise · Thaxton, VAPilot experienced engine vibration. Prop departed engine. Forced landing in a field.May 7, 1988 · Minor damage