Aviation Accident Summaries

Aviation Accident Summary NYC08LA293

Bristol, NH, USA

Aircraft #1

N2088Q

CESSNA 177RG

Analysis

The pilot computed that 1,500 feet of takeoff distance was required to clear a 50-foot obstacle, prior to beginning the departure from the 1,900-foot-long by 40-foot-wide runway. After performing a run-up check of the engine, the pilot taxied the airplane onto the runway and increased the engine power to full. The pilot released the brakes and the airplane began to accelerate. The airplane’s speed decreased slightly during the takeoff roll, but since the airplane was 2/3 down the runway, the pilot elected to continue the takeoff. As the airplane approached the 95-foot-tall trees located about 400 feet beyond the departure end of the end of the runway, the pilot decided to increase the flap setting to 20 degrees to help the airplane “balloon” over them, though this procedure is not listed in any takeoff or climb checklists for the airplane. After clearing the trees, the pilot decreased the flaps back to 10 degrees, and raised the landing gear, while aiming the airplane toward the lowest of the trees in front of him. The pilot attempted to maintain altitude as the stall warning horn sounded intermittently, but the airplane eventually struck the tops of the trees, before impacting the ground. Post-accident examination of the engine revealed “low” compression on the number one cylinder, with no other discrepancies noted.

Factual Information

On August 27, 2008, at 1521 eastern daylight time, a Cessna 177RG, N2088Q, was substantially damaged when impacted trees and terrain while departing from Newfound Valley Airport (2N2), Bristol, New Hampshire. The certificated commercial pilot and the pilot-rated passenger were seriously injured. Visual meteorological conditions prevailed, and no flight plan was filed for the flight, which was destined for Columbia County Airport (1B1), Hudson, New York. The personal flight was conducted under the provisions of 14 Code of Federal Regulations Part 91. According to a written statement submitted by the pilot, after performing an uneventful preflight inspection of the airplane, the pilot-rated passenger taxied the airplane, performed a run-up check of the engine, and set the flaps to 10 degrees. The pilot had previously computed that the airplane’s weight was 2,501 pounds, about 300 pounds below the airplane’s maximum gross weight, and that 1,500 feet of distance would be required during the takeoff to clear a 50-foot obstacle. The passenger then stated that she did not feel comfortable performing the takeoff, as the runway was “short” and there were numerous trees beyond the departure end of the runway along with rising terrain on either side of the airport. The pilot then taxied the airplane to the end of runway 21, where he held the brakes and increased the engine power to full. He noted that the engine gauges indicated 26 inches of manifold pressure and 2,550 rpm. The pilot then released the brakes and noted the airspeed increase to 55 mph, then briefly decrease to 52 mph. He momentarily considered aborting the takeoff; however, as the airplane had already traveled about two-thirds the length of the runway, he was unsure if the airplane would be able to stop. The pilot subsequently rotated the nose upward as the airspeed reached the rotation speed of 65 mph. After rotation, the pilot lowered the nose and increased the airspeed to 72 mph for the climb. As the airplane approached the trees near the end of the runway, the pilot decided to increase the flap setting to 20 degrees, to help the airplane “balloon” over them. After clearing the trees, the pilot decreased the flaps back to 10 degrees, and raised the landing gear, while aiming the airplane toward the lowest of the trees in front of him. The pilot attempted to maintain altitude as the stall warning horn sounded intermittently, but the airplane eventually struck the tops of the trees, before impacting the terrain shortly thereafter. Two witnesses, who the pilot and the passenger had visited during their time in Bristol, watched the airplane during the takeoff. The witnesses noted that what little wind prevailed at the time, favored runway 21. After taxing to the extreme end of the runway, the witnesses heard the engine power increase and saw the airplane move forward after the brakes were released. The airplane’s takeoff run took nearly the entire runway, and after the airplane became airborne, it veered to the left and disappeared over trees to the side of the departure path. Shortly thereafter the witnesses heard the sounds of impact. Another witness stated that she observed the airplane “trying to gain altitude” as it departed. The airplane yawed and turned right, narrowly avoiding contact with a utility line. The witness then heard a loud bang, similar to the sound of a car “backfiring,” as the airplane continued upward at an angle about 45 degrees, before it then straightened out about treetop level, and then descended in a nose down attitude into the woods below. The airplane was equipped with an engine trend monitoring device, which displayed engine data to the pilot in real-time, and recorded that data into non-volatile memory. The trend monitor was removed from the airplane and downloaded in the Safety Board Vehicle Recorders Laboratory. Examination of the data revealed that six parameters were recorded; which included battery voltage, fuel flow, oil temperature, fuel used, and four parameters each (one per cylinder) for cylinder head temperature and exhaust gas temperature. Each of the parameters was captured at six-second intervals. Review of data for the flight immediately preceding the accident flight revealed that the unit began recording at 1246:26 (internal unit time), and between this time and 1253:18, fuel flows were recorded between 2.4 and 7.1 gallons per hour (gph). At 1253:14, the fuel flow increased to 19.2 gallons per hour, before beginning a gradual decrease to, and stabilization around, 8.2 gph at 1308:44. Additionally, the fuel flow did not decrease below 12 gph until 1306:02. The data pertaining to the accident flight began recording at 1804:08, and between this time and 1806:38, fuel flows were recorded between 2.1 and 6.7 gph. At 1806:44, fuel flow peaked momentarily at 19.6 gph, before decreasing to 13.4 gph six seconds later. The fuel flow continued to decrease slowly until the final datapoint was recorded at 1807:20 and 10.8 gph. Following the accident, the fuel servo and nozzles were removed from the engine and were forwarded to the manufacturer for further inspection. External examination revealed that the fuel servo did not exhibit any impact-related or thermal damage. The fuel nozzles were also undamaged, and absent of debris. Flow testing of the system on a calibrated bench revealed no significant anomalies. Flow testing of the fuel nozzles revealed that three of the four met the required specification, while one performed 1.3 pounds (of fuel flow) under the specification. Additional disassembly and examination of the fuel servo components did not identify any anomalies that would have precluded normal operation. A Federal Aviation Administration (FAA) inspector examined the wreckage at an aircraft recovery facility on June 23, 2009. During the examination of the engine, continuity of the crankshaft was confirmed, and rotation of the crankshaft produced compression on all cylinders. The inspector noted that while performing the compression test on the engine, the number 1 cylinder was “low” with a reading of 20 over 80. All of the spark plugs exhibited “normal” wear and no anomalies were noted with the magnetos. Review of the airplane’s maintenance records revealed that the most recent annual inspection was completed on March 5, 2008. The engine oil and oil filter was replaced on the day prior to the accident. The engine was last overhauled on January 31, 2006, and had accumulated about 980 flight hours since that date. According to the normal takeoff checklist in the airplane's pilot operating handbook, the flaps can be set at 0 or 10 degrees for takeoff. The short field takeoff checklist specifies that the flaps should be set to 10 degrees for takeoff. The climb checklist specifies that the flaps should be raised upon reaching 80 mph. The pilot held a commercial pilot certificate with multiple ratings including airplane single engine land. He also held a flight instructor certificate, with included a rating for airplane single engine. The pilot’s most recent FAA second class medical certificate was issued in April 2008. The pilot reported he had accumulated 11,814 total hours of flight experience, 1,323 hours of which were in the accident airplane make and model. Newfound Valley Airport was comprised of a single 1,900-foot-long by 40-foot-wide asphalt runway, oriented in a 03/21 configuration. A 95-foot-tall tree was located 369 feet beyond the runway 21 departure end, 112 feet left of the runway centerline. The weather conditions reported at Plymouth Municipal Airport (1P1), Plymouth, New Hampshire, located about 11 nautical miles north of the accident site, at 1520, included calm winds, clear skies, 10 statute miles visibility, temperature 25 degrees Celsius (C), dewpoint 10 degrees C, and an altimeter setting of 30.07 inches of mercury.

Probable Cause and Findings

The pilot's failure to clear the trees during takeoff due to a partial loss of engine power for undetermined reasons.

 

Source: NTSB Aviation Accident Database

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