BFO94LA024

While in cruise flight at 6,000 feet MSL, the engine began to lose power. The pilot descended to an airport and made a precautionary landing. During the descent, engine power was restored. After landing, a mechanic examined the engine and found no discrepancies. The airplane was topped off with fuel and the engine was run up with no problems noted. The pilot took off and continued the flight. Upon reaching a cruising altitude of 8,000 feet MSL, the engine began to lose power again. The pilot attempted to adjust the fuel mixture control and boost pump, but with no success. The pilot declared an emergency and was vectored through the clouds for a landing at an airport. The pilot realized he did not have enough engine power to make the runway, so he force landed the airplane. The airplane hit light poles and terrain. An examination of the engine, associated fuel components, and fuel samples did not reveal any pre-impact deficiencies. The reported temperature at 7,000 feet MSL was minus 18 degrees f.

On January 15, 1994, about 1450 hours eastern standard time, N5088W, a Cessna P210N, operated by the owner/pilot, collided with terrain and was substantially damaged during a forced landing in New Castle, Delaware. The forced landing was precipitated by a partial loss of engine power during cruise flight. The certificated private pilot and one of the passengers received minor injuries, and another passenger received serious injuries. Visual meteorological conditions prevailed and a flight plan was not filed. The flight originated from Allentown, Pennsylvania, about 1415 hours, and was destined for Myrtle Beach, South Carolina. The flight was conducted under 14 CFR 91.

The pilot had owned and operated the accident airplane privately since 1985. He, his wife, and his daughter intended on flying to Key West, Florida, on a personal flight. The airplane was hangared (not fully enclosed) at the Duchess County Airport, in Poughkeepsie, New York.

On Thursday, January 13, the airplane was topped off with fuel and placed back in its hangar. On Saturday morning, January 15, 1994, the pilot arrived at the airport about 0900 hours eastern standard time. He pre-heated the engine for about 15 to 20 minutes, started the engine, and ran it up. No problems were noted. He filed an instrument flight rules flight plan to Key West, with a planned stop in Myrtal Beach, and took off from the Duchess County Airport.

No problems were noted during the climb and he leveled at 6,000 feet as filed. He was communicating with Allentown Approach Control at 6,000 feet when the engine "started ruining rough". He checked the Cessna cylinder head temperature gage and noted that it was "below the green," meaning it was cold. He attempted to lean the mixture to regain full engine power, but to no avail. He contacted Allentown Approach Control and requested a landing at the Allentown Airport.

As he descended to the airport, the engine "cleared up", and he landed uneventfully. Once he was on the ground, he ran up the engine and checked the optional digital cylinder head temperatures. He noticed that the no. 5 cylinder was indicating only about 120 degrees Fahrenheit. Normally, he thought it should be at about 1400 degrees Fahrenheit. He taxied to Dynair - Hangar 7, and parked the airplane. He requested that a mechanic look at the airplane, and a mechanic arrived about one hour later. He discussed the problem with the mechanic, and the mechanic pulled both spark plugs from the no. 5 cylinder. The spark plugs "looked OK", but the mechanic cleaned and gapped both of them anyway, and reinstalled them on the engine.

The airplane was again topped off with fuel. The engine was started and run up with no problems noted. A magneto check was performed with no problems noted. The pilot ran the engine up to 1700 RPM and performed the check; the RPM drops were "within limits." The pilot and his wife decided not to return home, but continued on to Key West, with a planned overnight stop in Myrtle Beach, South Carolina. He filed a new flight plan and departed from the Allentown Airport.

The cloud tops were at 7,000 feet, so the pilot requested and received clearance for 8,000 feet. No problems were noted for about ten minutes after the pilot reached 8,000 feet. Then, the engine began running rough again. The fuel pressure gage began "fluctuating." He attempted to adjust the mixture to hold 120 pounds per hour fuel burn, but the gage would then drop to 100 pounds per hour. He activated the fuel boost pump, and the fuel pressure climbed to about 160 pounds per hour and fluctuated. The backfiring got louder and more frequent, and the engine sounded as if it was being flooded, so he turned the boost pump off. He attempted to lean the mixture, but the fuel pressure "dropped way down." The fuel pressure gage was "all over the place, medium to high, medium to high." Also, his digital fuel flow totalizer did not agree with the Cessna fuel flow gage.

He contacted Philadelphia Approach Control and announced that he was having engine problems. He declared an emergency and was given clearance for descending turns through the clouds for an emergency landing at New Castle County Airport. When he descended below about 4,000 feet msl, he broke out of the clouds. He saw the airport and was cleared for a landing on runway 27. He lowered the landing gear and may have put in some flaps. The engine was "running very rough" at this point, and was "backfiring periodically." He attempted to adjust the mixture to regain full engine power, but to know avail. He realized that he did not have enough engine power to make the runway, so he told the airport tower controller that he would be making an off airport landing. He saw some buildings in front of him, so he force landed the airplane near an interstate off ramp. He may have selected more flaps at this time. The airplane first struck a light pole and came to rest in front of a tree.

The pilot further stated that his engine RPM was between 2450 and 2500 during this time, at 24 inches of manifold pressure. He remembered that he normally selected the fuel selector to the LEFT position for the first 30 minutes of flight, but that it may have been selected to the RIGHT side during the flight from Allentown. Also the pilot stated that the turbocharger appeared to be operating normally. The last time the pilot flew the airplane was on January 3, 1994. No problems were noted during this flight.

The reported surface temperature at the New Castle County Airport at the time of the accident was 13 degrees F. The winds were reported at 19 knots gusting to 24 knots from a magnetic bearing of 290 degrees. The reported temperature aloft at Atlantic City, New Jersey, located about 50 nautical miles northeast of the accident site, at 7,000 feet msl, was minus 18 degrees F. The report was made about four hours after the time of the accident.

An examination of the airframe and engine maintenance logs did not reveal any unresolved discrepancies prior to departure on the day of the accident.

An examination of the airframe and engine was performed on January 18, 1994, at the New Castle County Airport. No pre- impact deficiencies were found.

The fuel manifold valve, fuel pump, fuel mixture control valve, and fuel nozzles, were tested at Continental Motors on March 10, 1994, under the supervision of the NTSB. According to the FAA report, ". . . no abnormalities were noted that would have prevented the fuel system from functioning."