Aviation Accident Summaries

Aviation Accident Summary CHI95FA226

FESTUS, MO, USA

Aircraft #1

N82CA

PIPER PA-32-300

Analysis

SEVERAL WITNESSES WHO OBSERVED THE TAXI, RUNUP, AND TAKEOFF, REPORTED THAT THE ENGINE WAS BACKFIRING AND 'SNAPPING' OUT OF THE EXHAUST PIPE DURING THE RUNUP. IN HIS WRITTEN STATEMENT THE PILOT REPORTED THAT THE ENGINE WAS BACKFIRING DURING THE ENGINE START AND TAXI. HE ASKED THE MECHANIC, WHO WAS ALSO A PASSENGER IN THE AIRPLANE, 'IS THAT A PROBLEM?' THE MECHANIC RESPONDED THAT 'IT WAS NOT A PROBLEM BECAUSE THEY HAD JUST COMPLETED THE ENGINE RUN.' THE AIRPLANE APPEARED TO HAVE 'NORMAL' ACCELERATION DURING THE TAKEOFF RUN. IMMEDIATELY AFTER ROTATION, HE 'NOTED THAT THE AIRPLANE WAS NOT ACCELERATING...AFTER CLEARING A SECOND LINE OF TREES, I PUT THE NOSE DOWN BRIEFLY TRYING TO GAIN SOME AIRSPEED, BUT THE AIRCRAFT CONTINUED TO LOSE AIRSPEED AND ALTITUDE...THE AIRCRAFT'S LEFT WING HIT A TREE.' EXAMINATION OF THE ENGINE REVEALED ALL TWELVE SPARK PLUGS WERE SEVERELY WORN AND FOULED WITH LEAD AND CARBON DEPOSITS. THE RIGHT MAGNETO WAS MODERATELY FOULED WITH OIL AND HAD CARBON TRACKS IN THE DISTRIBUTOR. AIRCRAFT LOG BOOKS INDICATED THE ANNUAL INSPECTION WAS COMPLETED ON THE DAY OF THE ACCIDENT.

Factual Information

HISTORY OF FLIGHT On July 15, 1995, at 1510 central daylight time, a Piper PA-32- 300, N82CA, was destroyed when it impacted trees during takeoff in Festus, Missouri. The private pilot sustained serious injury and the three passengers sustained fatal injuries. The personal, 14 CFR Part 91 flight was planned to the Spirit of St. Louis Airport, St. Louis, Missouri. Visual meteorological conditions prevailed and no flight plan was filed. Several witnesses who observed the taxi, runup, and takeoff, reported that the engine was backfiring and "snapping" out of the exhaust pipe during the runup. They reported that the engine sounded as if it was not developing full power. One witness reported that he believed the pilot would abort the takeoff and was surprised when the airplane continued. One witness reported that the airplane became airborne within approximately the last 50 feet of the runway. It "dipped after takeoff, climbed slightly, dipped once more, climbed barely to tree top level and then sank out of sight over the treetops." In his written statement the pilot reported that the engine oil dip stick was warm when he checked it during his preflight inspection. He queried the mechanic who had been working on the airplane completing the annual inspection of the airplane, and was advised that they had just completed an engine run. The engine was backfiring during the engine start and taxi. He asked the mechanic, who was also a passenger in the airplane, "is that a problem?" The mechanic responded that "it was not a problem because they had just completed the engine run." The pilot reported that there were no backfires during the runup. The engine rpm dropped 125 rpm when he checked each magneto. He reported that he completed the checklist and asked "ready to fly?...each man affirmed with a nod." According to the pilot, the airplane appeared to have "normal" acceleration during the takeoff run. Immediately after rotation, he "noted that the airplane was not accelerating...after clearing a second line of trees, I put the nose down briefly trying to gain some airspeed, but the aircraft continued to lose airspeed and altitude...the aircraft's left wing hit a tree." WRECKAGE AND IMPACT INFORMATION The NTSB on-scene investigation began July 15, 1995, about 2130 central daylight time. The wreckage was located in a ravine about 1/2 mile south of the departure end of the runway 18. The main wreckage was submerged in a running stream with only the upper cabin and empennage above the water line. Branches of several large trees, north of the wreckage, were fractured and marked a descending 30 degree angle to the main wreckage. The left wing tip remained in one of the trees. The wreckage was extracted from the stream for examination. The lower nose was compressed upward at an angle of approximately 30 degrees and the engine mount was buckled downward. The bottom of the aft fuselage was compressed upward. A two foot section of the right wing leading edge, located about four feet outboard of the root, was compressed aft. The left wing spar was fractured at the root and the entire leading edge of the left wing was compressed aft. Fragmented tree branches and leaves were located in the leading edge of the left wing and in the tip of the vertical stabilizer. Examination of flight control and engine control continuity revealed no evidence of preimpact malfunction. One blade of the propeller was bent aft about 90 degrees, at midspan, and the other blade was bent slightly aft. No rotational scoring or leading edge damage was present. Fifteen gallons of fuel was measured in the right auxiliary fuel tank. The other three fuel tanks were ruptured. The fuel selector valve was positioned between the right main and right auxilliary tank positions. The valve was open to both tanks. Examination of the engine revealed all twelve spark plugs were threaded loosely in the cylinders. All were severely worn and fouled with lead and carbon deposits. Engine continuity and magneto timing were verified. The magneto leads sparked when the magnetos were rotated. Examination of the right magneto revealed moderate oil fouling and carbon tracks in the distributor. The inside of the magneto was moist from water submersion. Cross-firing was evident in the distributor when the magneto was rotated. TESTS AND RESEARCH The right magneto was bench tested, in the presence of a Federal Aviation Administration (FAA) Inspector, on July 21, 1995, by Teledyne Continental Motors (TCM), in Atlanta, Georgia. According to a TCM Investigator "there was no sign of arc-over between electrodes in the test stand. Unit runs smoothly at all speeds." The fuel injection servo and engine driven fuel pump functioned normally when they were bench tested by the NTSB. The PA-32-300 pilot's operating manual specifies the takeoff roll, for a maximum gross weight airplane using 10 degrees of flaps, at a density altitude of 2,700 feet, is about 1400 feet. The distance to clear a 50 foot obstacle under the same conditions is about 2,100 feet. ADDITIONAL INFORMATION Parties to the investigation were the Federal Aviation Administration, Flight Standards District Office, St. Louis, Missouri, The New Piper Aircraft, Inc., and Textron Lycoming. Following the on-scene portion of the investigation, the wreckage was released to Mr. Charles Johnson of Claims Analysis & Management Services, Inc.

Probable Cause and Findings

an improper annual inspection, the fouled spark plugs, the arcing magneto distributor, and the pilot's attempt to take off with known deficiencies.

 

Source: NTSB Aviation Accident Database

Get all the details on your iPhone or iPad with:

Aviation Accidents App

In-Depth Access to Aviation Accident Reports