NTSB Factual Report

HISTORY OF FLIGHT

On May 17, 1998, at 1416 eastern daylight time, N4537R, a Piper PA-28-140 was destroyed and consumed by fire after it collided with trees after takeoff from the Potomac Airfield Airport, Fort Washington, Maryland. Visual meteorological conditions prevailed and a flight plan was not filed. The certificated flight instructor (CFI) was fatally injured, the pilot rated passenger (PRP) sustained minor injuries, and the passenger was seriously injured. The personal flight was conducted under 14 CFR Part 91, and the intended destination was Annapolis, Maryland.

According to the private PRP, seated in the left front seat, the purpose of the flight was to familiarize him with instrument flight rules operations. Prior to the accident flight, the instructor took a passenger for an introductory flight. After the airplane landed, the instructor in the right front seat directed the passenger to sit in the right rear seat.

The PRP said that he back taxied the airplane to get more runway, because runway 6 was short and there were trees at the departure end of the runway. According to the PRP, shortly after rotation the instructor took over the controls and performed, "...what I thought was a maximum climb takeoff. He did not want me to do anything but sit there...I felt the plane sink after we were over the trees. It then crashed in the woods... ."

The PRP was interviewed by a Federal Aviation Administration (FAA) Inspector. He said that they did not use flaps for takeoff, "...they rotated at 70 knots and climbed at 70 knots...they did not compute the takeoff distance for the flight... ." He said that they had used runway 24 before as it was a "better runway." The FAA Inspector said the reported density altitude at the time of the accident was over 2,400 feet.

The passenger said that the weather was sunny, warm, quite muggy, and the visibility was not good due to haziness. The passenger also stated, "...our plane took off over the trees and felt heavy and sluggish ...the plane then began loosing altitude rapidly...the pilot...tried to take evasive measures...the plane continued its rapid descent. Our right wing clipped a tree and propelled the plane into a downward spiral... corkscrewed into the earth...the plane began to burn... ."

The accident occurred during the hours of daylight at about 38 degrees, 45 minutes north latitude, and 76 degrees, 56 minutes west longitude.

PILOT INFORMATION

The flight instructor, held a commercial pilot certificate with ratings for airplane single and multiengine land, and instrument airplane. He also held a flight instructor certificate for airplane single and multiengine land, and instrument airplane.

His most recent Federal Aviation Administration (FAA) second class medical certificate was issued on September 13, 1996, at which time he reported over 1,200 hours of total flight experience.

The PRP, held a private pilot certificate with ratings for airplane single and multiengine land.

His most recent FAA third class medical certificate was issued on June 30, 1997, at which time he reported over 200 hours of total flight experience.

METEOROLOGICAL CONDITIONS

At 1355 Andrews Air Force Base, Maryland, located about 10 miles east of the accident site, issued the following observation:

Sky condition, 25,000 feet scattered; visibility, 5 miles in haze; temperature, 90 degrees Fahrenheit (F); dew point, 68 degrees F; winds out of 010 degrees at 9 knots; and altimeter, 30.01 inches Hg.

WRECKAGE AND IMPACT INFORMATION

The airplane wreckage was examined at the accident site on May 17 and 18, 1998. Examination of the airplane wreckage revealed that all major components of the airplane were accounted for at the scene.

The airplane wreckage came to rest within the dimensions of the airplane, about 1 mile beyond the runway, oriented on a 180 degree magnetic heading. It was found underneath trees which were estimated to be about 85 to 90 feet tall. There was a fire which destroyed the cabin area, and all the flight instruments.

The right wing was separated from the fuselage and was found directly below the initial impact point. The right flap was separated and was located near the right wing. The left wing remained attached to the fuselage. The fuselage and forward section of the airplane was destroyed by fire.

Directly overhead of the wreckage, impact scars were observed on trees branches. Tree limbs were located with the right wing, and there was leading edge damage to the right wing similar to the tree branches observed.

The left flap actuator was found in the retracted position, while the position of the separated right flap could not be determined.

All flight controls surfaces were accounted for at the site, and control continuity was established to the rudder and elevator from the rear bulkhead. The horizontal stabilizer trim actuator measured 8 threads. According to the Piper Investigator, this represented 25-30 degrees nose up trim.

The engine separated from the fuselage and was located within the main wreckage. There was some tree impact marks and fire damage. The #3 exhaust pipe and muffler were crushed. The carburetor was secured but fire damaged. The throttle was at the idle position, the mixture was in the rich position. The propeller remained attached to the engine. One blade displayed "S" bends along outboard 50 percent of the blade with chordwise scratches. The other blade was bent aft approximately 20 to 30 degrees at outboard 1/3 span with chordwise scratches.

The top spark plugs were removed from the engine. The engine was manually rotated which resulted in the operation of the cylinder valves, and compression in all four cylinders was confirmed, using the thumb method. The left magneto was secured but destroyed by fire. It was removed and inspected. The shaft did not rotate. The right magneto was secured but destroyed by fire. It was removed and inspected. The shaft did not rotate.

Examination of the engine and airframe did not disclose any structural or mechanical anomalies.

MEDICAL AND PATHOLOGICAL INFORMATION

An autopsy was conducted on the pilot, on May 18, 1998, by the Baltimore Medical Examiner's Office, 111 Penn Street, Baltimore, Maryland.

Toxicological testing was conducted on the pilot by the FAA Toxicology Accident Research Laboratory, Oklahoma City, Oklahoma, on June 9, 1998. The toxicological report was negative for alcohol and positive for drugs. The report stated:

***0.004 ug/ml Tetrahydrocannabinol Carboxylic Acid (Marihuana) was detected in Lung Fluid. ***0.046 ug/ml Tetrahydrocannabinol Carboxylic Acid (Marihuana) was detected in Urine.

In the Code of Federal Regulations, 14 CFR 91.17, it stated, "No person may act or attempt to act as a crewmember of a civil aircraft...While using any drug that affects the person's faculties in any way contrary to safety... ."

ADDITIONAL INFORMATION

According to the PA 28-140 Handbook, the technique for a Short Field, Obstacle Clearance was as follows:

"Lower the flaps to 25 degrees (second notch) accelerate to 55-60 miles per hour and ease back on the control wheel to rotate. After breaking ground, accelerate to the best angle of climb speed, 74 miles per hour. Slowly retract the flaps when the obstacle has been cleared and continue to climb at 85 miles per hour."

A weight and balance was computed after the accident. The source of the weight and balance information was obtained from the pilots certificates, fuel log, and the third passenger weight was estimated. The weight of 2,053 lbs. and center of gravity of 90.44 in. was within the aircraft limitations.

The airplane wreckage was released to Mr. F. Tatebrigad, airplane owner on May 18, 1998.

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NTSB Probable Cause

The pilot's failure to maintain adequate airspeed, which resulted in a stall and collision with trees.