NTSB Factual Report

On January 12, 2002, about 1332 Alaska standard time, a tundra tire-equipped Piper PA-18 airplane, N9908D, sustained substantial damage during landing at Merrill Field, Anchorage, Alaska. The airplane was being operated as a visual flight rules (VFR) local area instructional flight when the accident occurred. An airline transport certificated pilot/flight instructor, and the private certificated pilot/owner, were not injured. Visual meteorological conditions prevailed.

During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on January 12, the flight instructor reported that she occupied the rear of the airplane, and was providing instruction to the airplane's new owner, who occupied the front seat. The pilot/owner had accrued 66 total flight hours, 14 hours as pilot-in-command, and .5 hours in the accident airplane. The instructor said that following a "three point landing" on the asphalt surface of runway 06, the airplane began to drift to the right. The instructor said she told the pilot to apply left rudder. At the same time, the instructor applied left rudder, but the airplane departed the right side of the runway into an area of snow. The airplane nosed over and received damage to the propeller, fuselage, and wing lift struts.

The instructor reported the accident flight departed Lake Hood Strip, Anchorage, and landed at Merrill Field about five minutes later. The flight was the pilot/owner's first flight in a tailwheel airplane. The instructor said that the middle of the runway at Merrill Field was sanded, but the edges of the runway were icy.

At 1335, an Aviation Routine Weather Report (METAR) at Merrill Field was reporting, in part: Wind, 050 degrees (true) at 3 knots; visibility, 10 statute miles; clouds and sky condition, 2,400 feet overcast; temperature, 25 degrees F; dew point, 19 degrees F; altimeter, 29.92 inHg.

In the Pilot/Operator report (NTSB form 6120.1/2) submitted by the instructor pilot, the instructor reported the airplane's right hydraulic brake reservoir was serviced before the flight. In addition, the instructor reported that a heater hose, routed to the rear seat, was installed the day before the accident flight. In the Pilot/Operator report, the instructor indicated the right brake felt as if it was locked. She included two previous NTSB reports containing references to locked brakes in the accident airplane make and model where the brake system was serviced before flight, and the utilization of a rear seat heater hose.

A review of the two previous accidents by the NTSB IIC disclosed State of Alaska PA-18 airplanes had locked brakes during landing, both within five days of each other in 1997. The previous NTSB accident reports involved two aircraft where a heater hose was directed onto the master brake cylinders after the brake cylinders were serviced. One of the accidents involved 1.5 hours of flight time before landing. The second accident involved 3 hours of flight time before landing.

The accident airplane's master brake cylinders are installed on the forward cockpit floor, adjacent to the front seat rudder pedals. The rear seat position does not have brake cylinders installed.

Following the accident, the airplane was recovered from the accident scene. No postaccident inspection of the brake system was conducted.

NTSB Probable Cause

The flight instructor's inadequate supervision of the flight. Factors in the accident were the student's failure to maintain directional control of the airplane during the landing roll, icy runway conditions, and snow-covered terrain along the runway edges.