NTSB Factual Report

HISTORY OF FLIGHT

On May 31, 2011, about 0845 central daylight time, a Cessna 150F, N7818F, impacted a sign and a tree during initial climb after a loss of climb performance from Sully Municipal Airport (8C2), Sully, Iowa. The airline transport pilot and the one passenger were uninjured. The airplane sustained substantial damage to the left wing, fuselage, and the left horizontal stabilizer. The airplane was registered to and operated by the pilot as a personal flight under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed and a flight plan had not been filed for the flight destined for Pella Municipal Airport (PEA), Pella, Iowa.

The pilot stated that he did not notice anything abnormal during the preflight and run-up of the airplane. He set flaps to 10 degrees for a takeoff on runway 8 (2,130 feet by 120 feet, turf). After a ground roll of about 700 feet, the airplane lifted off the runway and was flown in ground effect until the end of the runway where it yawed left 20 degrees. The airplane then contacted the ground and departed the runway end striking a sign and a tree.

The pilot stated that he assumed the he could depart the runway safely because it was indicated as such from the airplane performance charts.

AIRCRAFT INFORMATION

The airplane was a 1966 Cessna 150F that was powered by a Continental O-200-A engine, serial number 63047-6-A. The airplane was equipped with a McCauley 1A100 propeller.

The maximum gross weight of a Cessna 150F was 1,600 lbs. The pilot reported that at the time of the accident, the airplane weight was 1,521 lbs.

The last major overhaul of the engine was dated May 1, 1974.

An Engine Components Inc. (ECI), part number 641916 CP, serial number 04, cylinder assembly was installed on the engine during a top overhaul in 1993 at an airplane total time of 3,601 hours and 1,300 hours since major overhaul (SMOH). There were no records provided showing that the pistons had been replaced SMOH nor had they been replaced at the time of the top overhaul. According to the last annual inspection that was dated March 14, 2011, the airplane accumulated a total time of 3,782.7 hours and 1,485.8 hours SMOH.

Teledyne Continental Service Information Letter SIL98-9A, recommends a time between overhaul that engines be overhauled at least every 12 years.

McCauley Service Bulletin SB137AE states:

Fixed pitch propellers - 2,000 hours or 72 calendar months which ever occurs first*. Additionally, the propeller mounting bolt torque should be checked at least once per year. Propeller mounting bolts must be magnetic particle inspected in accordance with ASTM E-1444 or liquid

penetrant inspected in accordance with ASTM E-1417 or replaced at every overhaul. Propeller mounting bolts must be replaced whenever the propeller is involved in a blade strike as defined in Service Bulletin 176[X].

The 1966 Cessna 150 Owner's Manual takeoff performance section lists take off distance that is only based upon flaps retracted hard surface runways. Distances are to be increased 10 percent for each 35 degree F above standard for the particular altitude. At a gross weight of 1,600 lbs, 0 knot headwind, at sea level and 59 degrees F, and an indicated airspeed of 64 mph at 50 feet:

Ground run: 735 feet

Total to clear 50 foot obstacle: 1,385 feet

At 2,500 feet and 50 degrees F:

Ground run: 910 feet

Total to clear 50 foot obstacle: 1,660 feet

The pilot stated in his National Transportation Safety Board Pilot/Operator Aircraft Accident/Incident Report, Recommendation section, that he did not think the performance charts allow for an engine with 1,485 hours SMOH or a 45-year old propeller with a total time of 3,782 hours.

METEOROLOGICAL INFORMATION

The pilot stated that the winds were from 150 degrees at 12-15 knots.

A witness who had flown into 8C2 and landed on runway 26, stated that there was a strong crosswind from the south about 0830. He said that there were only 3 other airplanes at 3C2 that included the Cessna 150. He said a Decathlon departed runway 8 and was crabbing at least 30 degrees into a right crosswind from the south.

The following weather observations were recorded from Newton Municipal Airport, Newton, Iowa, (TNU) (9 nm northwest), Grinnell Regional Airport, Grinnell, Iowa, (GGI) (10 nm northeast), and Pella Municipal Airport, Pella, Iowa, (PEA) (11 nm southwest) at 0835:

TNU: wind - 190 degrees at 8 knots, temperature - 20 degrees Celsius (C), dew point - 18 degrees C, altimeter - 29.94 inches of mercury.

GGI: wind - 180 degrees at 10 knots, temperature - 21 degrees C, dewpoint - 18 degrees C, altimeter - 29.94 inches of mercury.

PEA: wind - 210 degrees at 6 knots, temperature - 19 degrees C, dew point - 17 degrees, altimeter - 29.93 inches of mercury.

According to NOAA/National Weather Service's Relative Humidity Calculator and based upon the temperature and dew point recordings from TNU, GGI, and PEA, the relative humidities were 88.29 percent, 83.01 percent, and 88.2 percent, respectively.

WRECKAGE AND IMPACT INFORMATION

The PEA airport manager stated that the runway grass was a little long but not over 6 inches. The runway was smooth with no rough or soft spots. He stated that there were tracks on the runway from the takeoff roll that disappeared about midfield (either due to the airplane being in the air or light on its wheels - [he] did not know) and then two tracks reappeared about 100-150 feet from the end of the runway veering left across the road and into a residential property.

The airport manager confirmed flight control continuity of the airplane prior to its recovery. There was about 12 gallons of fuel drained from the airplane.

Disassembly of the engine by a mechanic revealed that the number four cylinder rings were fractured.

TESTS AND RESEARCH

Federal Aviation Administration (FAA) publication, FAA-P-8740-7, The Safe Pilot's 12 Golden Rules, states to ensure that runway length is equal to the aircraft manufacturer's published takeoff or landing distance plus...80 percent safety margin if hard surface and double the manual distance if sod.

FAA publication, FAA-P-8740-2, Density Altitude, states, "...if high humidity does exist, it would be wise to add 10% to your computed takeoff distance and anticipate a reduced climb rate."

The Pilot's Handbook of Aeronautical Knowledge FAA-H-8083-25A, Chapter 10, Aircraft Performance states:

Performance charts allow a pilot to predict the takeoff, climb, cruise, and landing performance of an aircraft. These charts, provided by the manufacturer, are included in the AFM/POH. Information the manufacturer provides on these charts has been gathered from test flights conducted in a new aircraft, under normal operating conditions while using average piloting skills, and with the aircraft and engine in good working order. ...Always consider the necessity to compensate for the performance numbers if the aircraft is not in good working order or piloting skills are below average.

Examination of the cylinder assembly and piston was performed by the National Transportation Safety Board Materials Laboratory. The cylinder appeared intact with no apparent damage. The cylinder bore was smooth and exhibited a longitudinal mark that could not be felt. The base flange was painted orange indicating a chromium plated bore. The hardness and gradient were consistent with continued aging of the aluminum alloy during operation.

The piston was intact and had no cracks or erosion visible. The piston had three solid compression rings consistent with a 7.0:1 compression ratio piston.

The first (top) ring was broken in many pieces, the second (middle) ring was broken into two pieces, and the third compression(bottom) ring and oil control ring were intact.

Magnified optical inspections of the ring fractures revealed mechanical rubbing and damage that almost completely obliterated the fracture features.

Optical examination of the piston revealed extensive widening of the first piston ring slot. The widening was completely around the piston but was much wider in one quadrant of the piston. The quadrant area of the ring slot was wide enough to accommodate and trap two fractured pieces of the ring. The second ring slot also showed widening.

Pieces of the first and second rings appeared deformed with a flared cylinder contact face. Flaring was not readily apparent on the third ring. The flared appearance was not from deformation but selective material removal from the inboard and outboard faces of the ring slots.

Hardness measurements on the cross section of the piston showed a hardness gradient of 75.7 - 82.6 Brinell Hardness (HB) with softer material adjacent to the piston crown and harder material at the wrist pin boss. As manufactured, a minimum of approximately 98 HB is required.

The pilot said that he will not depart 2,100 foot long runways with a road at the end and no clear zone or overrun area.

NTSB Probable Cause

The pilot's failure to attain an adequate climb rate during the initial takeoff, resulting in the airplane settling back down and departing the runway. Contributing to the accident was the pilot's inadequate preflight planning and preparation.