Pilot Debrief

VIKING (Clarke) Dragonfly near Freeport, IL — 2015-09-08

Final reportCEN15LA402
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Date
2015-09-08
Location
Freeport, IL, USA
Airport
KFEP
Aircraft
VIKING (Clarke) Dragonfly
Registration
N24TL
Category
Airplane
Highest injury
Serious
Fatalities
0
Phase of flight
Initial climb

Probable cause

The airplane’s degraded climb performance due to its being over its maximum gross weight and a hole in the engine exhaust.

NTSB narrative

The private pilot was conducting a personal flight in the experimental airplane. The pilot reported that, during the takeoff roll, he observed a "puff" of smoke emanate from the engine's left side and noted that the airplane did not accelerate as quickly as it normally did. The pilot leaned the mixture control, which was at 3/4 rich, and the engine subsequently started to develop normal power. The airplane lifted off about midfield and 80 mph. When the airplane reached about 150 to 200 ft above the ground, the pilot noticed that it was not climbing as he would have expected. The manifold pressure was 47 inches, and he was concerned about "overboosting" the engine, so he reduced the manifold pressure to 40 inches, and the airplane then started to descend. The pilot increased the manifold pressure to 45 inches, but the airplane continued to descend. The pilot chose to perform a forced landing to a field, during which the airplane struck a wire fence and then the ground. During postaccident examination, the engine started without hesitation and ran up to 40 inches of manifold pressure for several minutes. Examination of the engine revealed a 1/2-inch square crack in the exhaust pipe. No other anomalies were noted with the engine or its systems. An examination of the airframe, flight controls, and remaining systems revealed no anomalies. The takeoff weight of the airplane at the time of the accident was estimated to be 1,310 lbs, which was 110 lbs over the airplane's maximum gross weight. It is likely that the combined effects of the hole in the exhaust pipe and the airplane being over its maximum gross weight negatively affected the airplane's climb performance during takeoff.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Pilot could have aborted takeoff after noticing engine power issues.

NTSB coding

Evidence available

  • 3 docket documents
View NTSB final reportView NTSB docket

Docket documents3

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