NTSB Factual Report

On September 1, 2009, at 1053 eastern daylight time, a Piper PA-28-151, N32146, was substantially damaged during a forced landing in Mansfield, Massachusetts. The certificated commercial pilot and passenger were not injured. Visual meteorological conditions prevailed, and no flight plan had been filed for the local flight which originated at Laurence Hanscom Field Airport (BED), Bedford, Massachusetts, at 1010. The personal flight was conducted under the provisions of 14 Code of Federal Regulations Part 91.

According to the pilot, prior to takeoff he performed a pre-flight inspection and "topped off" the fuel tanks. He strained the fuel tanks and noted no contamination. The pilot also noted no anomalies during the pre-flight inspection or the subsequent run-up inspection.

The pilot departed to the northeast, flew around Boston, and then toward Gillette Stadium. As the airplane was southeast of the stadium, the pilot performed a power-on stall at an altitude of 2,500 feet. Shortly after recovery from the stall, the airplane's engine started to "sputter and run rough." The pilot turned the carburetor heat on, adjusted the airplane's pitch attitude to maintain "best glide airspeed," and flew toward the Mansfield Airport. The airplane's engine maintained 1500 RPM. The pilot noted the oil pressure, oil temperature, and fuel pressure were "in the green." Both fuel tanks indicated "plenty of fuel," and the pilot subsequently switched fuel tanks.

The pilot realized the airplane would not be able to reach Mansfield Airport and prepared for a landing on the highway below (I-495). During the approach, he overflew a sign and touched down prior to an overpass. The left wing struck a barrier during the landing, and the airplane came to rest on the side of the highway.

Examination of the airplane after the accident by a Federal Aviation Administration (FAA) inspector revealed substantial damage to both wings and the nose of the airplane. Fuel was drained from the right fuel tank, and no contamination was noted in the fuel. The left fuel tank was ruptured during the accident. The engine crankshaft was rotated, and valvetrain continuity and thumb compression was confirmed on all cylinders. Testing of both magnetos revealed spark at all terminal leads, and examination of the spark plugs revealed normal wear. No anomalies or contamination was noted with the fuel pump or fuel lines.

The pilot held a commercial pilot certificate with ratings for airplane single-engine land and instrument airplane. He also held a flight instructor certificate with a rating for airplane single engine. His most recent FAA second-class medical certificate was issued on January 29, 2009. At the time of the accident, the pilot reported 664 hours of total flight experience, 64 of which were accumulated in the previous 90 days.

Examination of the airplane and engine logbooks revealed the airplane was on an Approved Inspection Program. The most recent inspection was performed on the airplane on August 13, 2009 at a tachometer time of 917 hours. The engine had accumulated 774 hours since major overhaul.

Weather reported at Norwood Memorial Airport, about 10 miles from the accident site, at 1053, included wind from 350 degrees at 4 knots, 10 miles visibility, clear skies, temperature 68 degrees F, dew point 45 degrees F, and altimeter setting 30.29 inches mercury.

Review of the FAA carburetor ice probability chart revealed that the temperature and dew point at the time of the accident were conducive to "serious icing" conditions at glide power.

NTSB Probable Cause

A loss of engine power due to carburetor icing as a result of the pilot's delayed use of carburetor heat.