Plymouth, MA, USA
N29496
PIPER PA-28-161
After performing several takeoffs and landings on runway 24, the certified flight instructor (CFI) elected to use the grass area parallel to runway 33 in order to demonstrate soft-field takeoffs to the student pilot. Once airborne the CFI lowered the nose of the airplane in order to accelerate to their predetermined climbout speed of 79 knots indicated airspeed (KIAS). According to the CFI, the airplane accelerated fairly normally to 55 KIAS, then slowly accelerated to 60 KIAS, at which point the airspeed "stagnated." The CFI made the decision to discontinue the takeoff and land on the remaining portion of the grass area. She allowed the airplane to "float over" the paved portion of a perpendicular runway and touched down on the main landing gear on the other side of the paved portion. The airplane made contact with a low berm and the nosegear collapsed. The grass area that was used for this flight was not a runway and was approximately 1,000 feet in length. The pilot operating handbook for this airplane make and model does not prohibit the departure from a non-paved surface area; however, the only performance data that was provided by the manufacturer requires a "paved, level, dry runway."
HISTORY OF FLIGHT On June 20, 2009, about 1445 eastern daylight time, a Piper PA-28-161, N29496, was substantially damaged when it impacted the ground during a rejected takeoff from Plymouth Municipal Airport (PYM), Plymouth, Massachusetts. The certificated flight instructor (CFI) and student pilot received minor injuries. Visual meteorological conditions prevailed and no flight plan was filed for the local training flight, which was conducted under the provisions of 14 Code of Federal Regulations (CFR) Part 91. According to a written statement from the CFI, the flight originated at the accident airport and departed about 1345, at which time the flight climbed to 4,500 feet above mean sea level in order to practice some training maneuvers. Approximately 30 minutes later, they "simulated [an] emergency descent" and entered the downwind leg of the traffic pattern for runway 24. During a phone interview with the CFI, she reported that during their simulated emergency descent some instructors utilize carburetor heat, which she did also. They performed the simulated emergency descent as a steep spiral, and every 500 to 1,000 feet of altitude loss, she would apply power and then retard the power to continue the simulated emergency in order to verify that the engine was able to perform with power when needed. After the completion of the "simulated emergency descent," the flight remained in the traffic pattern for runway 24 and practiced several takeoffs and landings. After about 15 minutes, the CFI elected to change runways and continue practicing takeoffs and landings. The CFI elected to demonstrate a soft-field takeoff, selected 25 degrees of flap extension, applied full power and checked the gauges. Upon liftoff, the CFI lowered the nose of the airplane to allow it to accelerate to their target airspeed of 79 knots indicated airspeed (KIAS). After accelerating through 55 KIAS, the acceleration rate became "stagnant," and at 60 KIAS the airplane did not appear to accelerate any further. The CFI then announced that they were "aborting takeoff," reduced power, and positioned the airplane into an attitude for landing. The CFI, concerned about "getting caught" on the pavement for runway 24, which was perpendicular to their flight path, allowed the airplane to "float over the pavement" prior to touching down. The airplane touched down on the main landing gear and began to decelerate. As it began to slow, the nosewheel struck a "soft/elevated patch of grass," collapsing the nose gear and causing the airplane to nose over. The CFI did not notice if there was a decrease in the rpm of the engine prior to the decision to discontinue the takeoff. An eyewitness, located approximately 800 feet from the airplane's touch down, reported that he "heard no loud or unusual noise from the aircraft prior to touchdown." PERSONNEL INFORMATION The CFI, age 23, held a commercial pilot certificate, with ratings for airplane single-engine land, airplane multiengine land, and instrument airplane. She also held a flight instructor certificate with a rating for airplane single-engine land. Her most recent Federal Aviation Administration (FAA) first-class medical certificate was issued March 21, 2007. The CFI reported 359 total hours of flight experience, 273 total hours of flight experience as pilot in command, 57 hours of flight experience as a CFI, 42 total hours in the accident aircraft make and model, and 24 hours in the accident aircraft make and model as a CFI . The student pilot, age 32, held an FAA third-class medical certificate, which was issued March 27, 2009. He reported 32 hours of total flight experience and 28 hours in the accident aircraft make and model. AIRCRAFT INFORMATION The airplane was issued an airworthiness certificate with the FAA on April 20, 1979 and was registered to the owner on July 21, 1993. It had 12,140 hours of service at its last 100-hour inspection, which was April 2, 2009. It was equipped with a Lycoming O-360-D36 engine, which had 8,534.7 hours total time in service, 1,952 hours total time since overhaul, and 61 hours since the last inspection. METEOROLOGICAL INFORMATION The 1452 recorded weather observation at PYM, included wind from 210 degrees at 7 knots, visibility 10 miles, few clouds at 3,000 feet above ground level (agl), scattered clouds at 3,700 agl, temperature 23 degrees C, dew point 18 degrees C, altimeter 29.62 inches of mercury. The previous reported weather observation at PYM included winds from 230 at 7 knots. AIRPORT INFORMATION The airport has no air traffic control tower and has two crossing runways. The longest runway was 6/24, which was 4349-foot-long and 75-foot-wide. The crossing runway is 15/33, which was 3,351-foot-long by 75-foot-wide. The grass area in which the flight was utilizing for departure was parallel to and on the north side of runway 15/33 and intersected runway 6/24. According to airport operations personnel, the grass area is not designated as a runway; however, was utilized by the flight school. Airport personnel further stated that regular mowing is the only maintenance done to this area and that the approximate length prior to intersecting runway 6/24 was 1,000 feet. Utilizing the airport diagram, a measurement of this area was in a range of 1,000 to 1,545 feet. After this accident, the flight school enacted a new policy prohibiting operations on the grass area at the accident airport. WRECKAGE AND IMPACT INFORMATION The airplane came to rest approximately 1,000 feet west-northwest of the runway 6/24 centerline, on the top of the vertical stabilizer and the top of the fuselage. The nose over damaged the rudder, vertical stabilizer, propeller, wing spar, and the fuselage. ADDITIONAL INFORMATION The performance section of the airplane's pilot operating handbook revealed that there were no performance charts to utilize for a takeoff from other than a paved surface and included a warning in section 5.3, "Performance information derived by extrapolation beyond the limits shown on the charts should not be used for flight planning purposes." However, calculating the performance from the information supplied by the CFI and the airport, the calculated takeoff ground roll was approximately 950 feet. This calculation had limitations applied such as a dry, paved runway. Utilizing the wind information reported approximately 7 minutes after the accident, the takeoff ground roll would have been approximately 1,075 feet. Several common FAA pilot-oriented references were examined for information regarding the effects of turf runway surfaces on takeoff and ground roll distance. These were the Aeronautical Information Manual (AIM), the Airplane Flying Handbook (FAA-H-8083), Aircraft Weight and Balance Handbook (FAA-H-8083-1A), and FAA Advisory Circular 60-22 Aeronautical Decision Making. One FAA publication provided some qualitative information regarding takeoffs on other than dry paved runway surfaces. In Chapter 8 of the Pilots Handbook of Aeronautical Knowledge (FAA-H-8083-25), the section entitled "Weight and Balance Restrictions" stated in part that "The airplane’s weight and balance restrictions should be closely followed. … Although an airplane is certified for a specified maximum gross takeoff weight, it will not safely take off with this load under all conditions. …Other factors to consider prior to takeoff are runway length, runway surface, runway slope, surface wind, and the presence of obstacles. These factors may require a reduction in weight prior to flight." Also in Chapter 9, the section entitled "Aircraft Performance" states that "Any surface that is not hard and smooth will increase the ground roll during takeoff. This is due to the inability of the tires to smoothly roll along the runway."
The CFI's inadequate preflight planning and delay to abort the takeoff from the soft takeoff area.
Source: NTSB Aviation Accident Database
Aviation Accidents App
In-Depth Access to Aviation Accident Reports
