Aviation Accident Summaries

Aviation Accident Summary NYC03LA097

Buffalo, NY, USA

Aircraft #1

N448VP

Piper PA-23-250

Analysis

The pilot was approaching to land on runway 23 with a tower reported wind from 170 degrees at 10 knots. He reported that at 20 feet, and an airspeed of 100-110 mph, the airplane fell to the runway. The airport was equipped with a low level windshear detection system. According to data from 2 minutes before the accident to 2 minutes after the accident, from the on-airport sensors, the wind was variable by 40 degrees, and the velocity changed by about 5 knots.

Factual Information

On May 5, 2003, at 1929 eastern daylight time, a Piper PA-23-250, N448VP, operated by Northeast Aviation, as flight 606, was substantially damaged while landing at the Buffalo Niagara International Airport (BUF), Buffalo, New York. The certificated commercial pilot and additional crewmember were not injured. Visual meteorological conditions prevailed for the non-scheduled cargo flight, which originated from Dutchess County Airport (POU), Poughkeepsie, New York. Flight 606 was conducted on an instrument flight rules (IFR) flight plan under 14 CFR Part 135. According to the operator, the additional crewmember was onboard to observe operations and assist with the cargo. He held a commercial pilot certificate, and was being considered for employment. He had not passed a flight check for the airplane and was not operating as a pilot on the operator's certificate The pilot reported that the flight to Buffalo, was without incident. When he initially obtained the ATIS (Airport Terminal Information Service), the winds were "gusty." The airplane was radar vectored for the ILS 23 approach. At the outer marker, the landing gear was lowered, and the pilot performed a "GUMP" check. The pilot further stated: "...I was approaching at 100-110 mph. Slowly started to power back over the runway. Just when I was about to begin the flare, I felt the bottom drop out below me. I was going to full power, but by that time, I had hit the ground so I pulled the power back to idle. Next thing I knew we were skidding down the runway...." The additional crewmember reported that as the airplane crossed the threshold for runway 23, it just stopped flying and struck the ground. The pilot added power, but there was insufficient time to prevent runway contact. He was not observing the airspeed and was unaware of the airspeed at the time the airplane encountered what he described as "wind shear." In addition, he reported that he did not touch the flight controls during the approach or landing. A witness stated: "...I was directly under the aircraft as it was on its final approach across I-90. I noticed that the aircraft was really being pitched by the winds and making very radical moves to correct alignment (all this happened in a couple of seconds). As the aircraft approached the end of the runway, the aircraft seemed to be having difficulty getting alignment. As the aircraft aligned over the runway, the aircraft made a very sudden and hard drop on to the runway. I did not see actual contact by the aircraft, but I did witness subsequent smoke after the touchdown...the contact seemed hard and very fast from approximately 20 feet." According to an inspector from the Federal Aviation Administration (FAA), the airplane struck the runway, on centerline, about mid-way from the approach end of runway 23 and taxiway BRAVO. It slid for about 500 feet, and came to rest at the intersection of taxiway BRAVO, with the airplane partially off the runway. The landing gear had collapsed rearward. The outboard section of the left wing had scrape marks on the underside. There were no scrapes on the underside of the right wing. A small post-crash fire developed in the left engine nacelle, and was extinguished by airport fire fighting personnel. Buffalo airport was equipped with a low level wind shear detection system. It consisted of 2 on-airport and 4 off-airport sensors. Data was sampled every 10 seconds at each sensor, and recorded using UTC time (local time + 4 hours). According to FAA data, the time of the accident was listed as 1929 (2329 UTC). Data between 2257:10, and 2359:50 was received. A detailed examination of the data between 2327, and 2331 revealed that for the 2 on-airport sensors, the maximum variation in wind direction was 40 degrees, and the maximum spread in wind velocity was 5 knots. For the sensor located in the northeast quadrant, the direction the pilot approached from, the maximum variation in wind direction was 40 degrees, and the maximum spread in wind velocities was 12 knots. According to the airplane owner's manual, the stall speed of the airplane with landing gear extended, and a flap setting of 50 degrees is 68 mph at 5,200 pounds, and decreases to 61 mph at 4,200 pounds.

Probable Cause and Findings

The pilot's failure to maintain sufficient airspeed to prevent an inadvertent stall. Factors were the variable and gusty winds.

 

Source: NTSB Aviation Accident Database

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