Aviation Accident Summaries

Aviation Accident Summary NYC97LA014

PAWTUCKET, RI, USA

Aircraft #1

N36JM

Cessna 340A

Analysis

The pilot was conducting the localizer approach to runway 15 when the aircraft overran the runway and struck an obstacle. According to the pilot, a loss of power occurred in both engines as he attempted to do a missed approach, and the airspeed subsequently decreased from 105 to 80 knots. The pilot reported that he pushed the nose over to avoid a stall, broke out of the clouds over the mid-point of the runway, landed long and continued off the end of the runway into terrrain and a tower structure. A witness reported the 'aircraft broke out of the clouds just above the trees north of runway 5 and west of runway 15. Reportedly, the aircraft was being banked from a right to left to get aligned with runway 5, flaps appeared to be up, and the gear was down. The witness said the engines sounded to be at idle and at high rpm, and the aircraft appeared to be 50 feet above the ground at midfield when it went out of sight behind hangar.' The weather observed at the time of the accident was in part: ceiling 100 feet overcast, visibility 0.5 mile with fog and rain. The published landing minimums for the approach was ceiling 400 feet and visibility 0.75 mile. Recorded radar data of the flight indicated a descent below the minimum descent altitude at a constant airspeed. Both engines started immediately and ran during a postaccident check of the aircraft.

Factual Information

On November 7, 1996, at 0900 eastern standard time, a Cessna 340A, N36JM, sustained substantial damage when it collided with terrain after landing on runway 05 at North Central State Airport (SFZ) in Pawtucket, Rhode Island. The certificated airline transport pilot and commercial pilot passenger received serious injuries. The third occupant, an infant, was uninjured. Instrument meteorological conditions prevailed and an IFR flight plan was filed for the flight conducted under 14 CFR 91. The aircraft departed Nantucket Memorial Airport (ACK) at 0815 destined for Pawtucket. In a telephone interview, the pilot reported that the airplane was established on the Localizer Runway 05 approach at North Central State Airport (SFZ). He said the airplane was at the minimum descent altitude of 820 feet mean sea level (MSL), 1.9 miles DME from the runway threshold when he began to prepare for the missed approach. The pilot stated that he knew he "...wasn't going to get in because the cloud cover was too thick." He stated that when he pushed the mixture, propeller, and power levers forward he felt no "...surge...", no corresponding increase in propeller or engine RPM. The pilot said the airplane experienced a "...power loss and airspeed degeneration." He said the power loss was on both engines, the aircraft continued "...straight ahead...", and no rudder input was required to keep the nose straight. The pilot explained that the airspeed decayed from 105 knots to 80 knots. He said, "I pushed the nose over to avoid a stall..." and subsequently "...spotted the runway, I knew we were too far down. I decided I would rather land long..." than continue and chance uncertain terrain beyond the airport. He said, " If the runway was dry, I probably would have made it, but we were hydro-planing the whole way down." The aircraft continued off the end of the runway and impacted terrain and a tower structure. At the scene, the pilot reported to an Inspector from the Rhode Island Airport Corporation that he hit the tower at "...100 miles an hour or knots, whatever." A police officer reported the pilot said "...he lost power to one of his twin engines for an unknown reason." In a telephone interview, the copilot was questioned about the airplane's performance at the missed approach point. She said, "It felt like we were still back on the props and throttle...like we were stuck in mud." She stated that she did not recall airspeeds or altitudes nor did she hear the stall warning horn. The copilot reported that she was not briefed about the weather conditions at North Central State Airport prior to departure but that she did hear the ATIS report enroute. The copilot is a commercial pilot with a Multi-engine Land Instrument rating. She has approximately 400 hours of flight time with "...about two-thirds multi-engine." Radar data provided by the Federal Aviation Administration shows N36JM descending to 800 feet (MSL) and then continuing the descent to 600 feet (MSL). The last radar plot at 800 feet places N36JM approximately 1.3 miles from the runway. The radar plot at 600 feet places N36JM approximately .6 miles from the runway. The airspeed throughout this portion of the approach was 113 knots +/- 3 knots. Airport elevation at North Central State is 441 feet. The purpose of the flight was to bring N36JM to North Central State Airport (SFZ) for propeller maintenance. An Airframe and Powerplant Mechanic at SFZ reported in a written statemant, "On November 7, 1996 at about 8:30 am, I received a call from [the copilot] telling me they were coming in. She asked about the weather and I said it did not look good. She said that they may have to go to T.F. Green [Airport] and wait and tell the prop man to wait. At about 9 or 9:15 I heard the [engines] of a twin [aircraft]. Mike stepped out the door and said it was [N36JM] then everything went quiet." Another witness wrote, "Aircraft broke out of the clouds just above the trees North of Runway 5 and west of Runway 15. Aircraft was banking from a right to left hand bank to get aligned with Runway 5. Flaps appeared to be up, gear was down. Engines sounded to be at idle, high RPM, through the window. Appeared to be 50 feet above the ground at midfield when the aircraft went out of sight behind hangar." The pilot checked the weather at North Central State Airport at approximately 0852 using the Automated Terminal Information Service (ATIS) at SFZ. The weather reported at that time was: measured ceiling 100 feet overcast with one-half mile visibility, wind from 140 degrees at 4 knots, temperature 48 degrees and dew point 44 degrees, altimeter setting 30.36" Hg. The same observation was reported at SFZ prior to N36JM departing ACK. Published weather planning minimums for the Straight-in Localizer Runway 5 Approach at SFZ is ceiling 400 feet and visibility 3/4 mile. An examination of the airplane by Federal Aviation Administration Safety Inspectors revealed no mechanical deficiencies. Utilizing a loaner propeller, each engine started and ran individually while still attached to the airframe. Because the left-side fuel system was damaged, a fuel line was plumbed from the right side to the left engine. Damage to both the left and right engine mounts prevented running either engine to full operating RPM. Each engine started immediately, idled smoothly, and accelerated to 1700 RPM (right) and 1300 RPM (left) respectively. ADDITIONAL INFORMATION In a letter dated January 14, 1997, the pilot stated: "The "Aux Pumps L" circuit breaker was noted to be open on 36JM post crash. My information is that this breaker controls both the auxiliary fuel pump noted in ME888-3 (see enclosed photocopy) AND the auxiliary fuel tank in line fuel pump which runs when AUX fuel is selected via the fuel selection valve. I believe that the open condition of this circuit breaker could have caused vapor lock and a loss of engine power on the left engine during the attempted missed approach." Examination of the wreckage by a Federal Aviation Administration Aviation Safety Inspector (Airworthiness) revealed: "...2 circuit breakers popped L/H landing light and L/H AUX fuel trans pump/ possible cause bundle sheared in half in L/H wing leading edge." In a telephone interview November 8, 1996, the pilot stated that he took off with the main tanks selected, switched to the auxiliary tanks enroute, then switched back to the main tanks "...prior to talking to Providence Approach."

Probable Cause and Findings

failure of the pilot to comply with the published instrument approach procedure, by continuing the ILS approach below the decision height, rather than performing a missed approach; and his failure to attain a proper touchdown point for the continued landing. Factors relating to the accident were: weather below approach minimums, wet runway, and hydroplaning conditions.

 

Source: NTSB Aviation Accident Database

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