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On August 16, 2007, about 1124 eastern daylight time, a Cessna 172N floatplane, N738JE, was substantially damaged when it impacted terrain shortly after takeoff from Irondequoit Bay near Rochester, New York. The certificated pilot/owner and a pilot-rated passenger/owner were fatally injured. The personal flight was operated under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed at the time of the accident. A visual flight rules (VFR) flight plan to Arnprior, Ontario, Canada was filed, but not activated by the pilot.
The accident airplane was part of a two-airplane, six-person, weekend fishing trip destined for Quebec Province, Canada, with a return planned for 3 days later. The other four persons on this trip departed a few hours earlier in a Grumman Widgeon. The pilot of the Widgeon reported that his airplane took "all the gear and provisions," for the six persons, and stated that the accident airplane only had to transport the other two persons, and "clothes, sleeping bags and fishing gear." The pilots planned to clear customs at Arnprior, located 160 miles northeast of Rochester, and then continue north to Clova, Quebec, located 190 miles north of Arnprior.
Eyewitnesses reported that the airplane left its ramp at a marina on the south end of the bay, taxied north for a while, turned around, and began its takeoff run to the south. Acquaintances of the pilot said that the usual starting point for a takeoff run to the south was opposite Snider Island, located approximately 4,500 feet north of the marina. After what witnesses considered a "normal takeoff," the airplane climbed to a point just north of the south end of the bay, where it made a left turn to the east. Several witnesses described the airplane's speed as "slow" or "too slow." Shortly thereafter, the airplane banked to the left, descended steeply, and impacted terrain. Multiple witnesses described the descent as "nose first." One witness stated that "the plane started to roll like a corkscrew," and that when he last saw it airborne, it was "upside down." Most witness estimates of the airplane's altitude at the start of the descent were between 150 and 500 feet above ground level.
The airplane impacted in a field approximately 1,500 feet east-northeast of its ramp, and approximately 1/2 mile east of its takeoff path. According to witnesses, a fire broke out immediately, and the airplane continued to burn. No witnesses reported observing smoke or fire prior to impact.
The pilot, seated in the left seat, held a private pilot certificate with airplane single engine land (ASEL), airplane single engine sea (ASES), and instrument ratings. He began his flight training in July 1997, and began his SES training in April 2004. According to his logbook, the pilot had approximately 1,140 total hours of flight experience, 250 hours ASES, and 125 hours of actual instrument time. The pilot had approximately 230 hours of flight time in the accident airplane, and 24 of these were within the 30 days prior to the accident. His most recent Federal Aviation Administration (FAA) third-class medical certificate was issued on August 18, 2005
The passenger, seated in the right seat, held a private pilot certificate with airplane multiengine land (AMEL), ASEL, and ASES ratings. He reported 972 total hours of flight experience on his most recent application for an FAA third-class medical certificate, dated June 2003. Acquaintances indicated that the passenger continued to fly, but only under the provisions of a sport pilot certificate.
The accident airplane was a 1978 Cessna 172N. At the time of the accident, the airplane was equipped with a Lycoming O-360-A1D engine, a McCauley Kliptip propeller, model DFA8242, and EDO model 689-2130 floats.
Records indicate that the airplane was delivered from Cessna with 'landplane' landing gear, and that in April 1978, the airplane was converted to a floatplane. This was documented on a Federal Aviation Administration (FAA) Form 337, "Major Repair and Alteration," which indicated that EDO model 689-2130 floats were installed in accordance with Kenmore Air Harbor Inc. supplemental type certificate (STC) SA584NW. Another Form 337 documented the March 1981 removal of the O-320-H2AD engine, and installation of an O-320-E2D engine, in accordance with Kenmore STC SA1191NW.
In April 1986, another Form 337 documented the removal of the O-320-E2D engine, and the installation of an O-360-A3A engine, in accordance with Penn Yan Aero STC SA332GL. The serial number listed on the Form 337 matched that on the data plate of the accident engine, but the engine model designators on the Form 337 and engine data plate ("A3A" and "A1A," respectively) did not match. The same Form 337 documented the installation of a McCauley model 1A200/DFA propeller, while other maintenance records referred to the propeller as a McCauley Kliptip model DFA8242. In September 1993, two 337 forms were filed that documented the incorporation of STC numbers SA2600CE and SE2563CE. These two STCs permitted the use of "autogas," and the intermix of autogas and aviation gasoline, on the airframe and in the engine.
The accident airplane was registered to a corporation. At the time of the accident, the two persons on board, along with a third individual, were the owners of the corporation. The corporation acquired the airplane in May 2002. At the last annual inspection in May 2007, the airframe total time (TT) in service was approximately 4,957 hours. The pilot's logbook indicated that he logged approximately 13 hours in the airplane since the annual inspection. No records substantiating the engine time were located.
Each float was constructed with eight separate internal compartments. Preflight inspection procedures required that each of these compartments was to be visually checked for water, and that any water was to be removed prior to flight. Access to each compartment was by means of a removable cover. One partner of the airplane stated that "this plane didn't leak."
Cessna records indicated that the airplane was equipped with a pneumatic-type stall warning system that consisted of an inlet on the leading edge of the left wing, plumbed with plastic tubing to an air-operated horn located near the upper left corner of the windshield. As the airplane approached a stall, the negative pressure at the leading edge inlet would draw air through the horn assembly, and sound an audible warning. This resulted in a warning at 5 to 10 knots above stall in all flight conditions. The inlet was located approximately 5 feet above, and 5 feet outboard of, the float. The Cessna Pilot Operating Handbook (POH) stated that the system functionality could be tested during preflight inspection by the application of suction to the leading edge inlet.
National Transportation Safety Board investigators acquired copies of the maintenance provider's service orders for the airplane. One service order, dated October 8, 2004, contained the entry "NOTE: Airspeed reads 40 knots on ground, and it reads 20 knots high at all speeds." These values are not in compliance with the accuracy requirements for airspeed indicating systems set forth in Paragraph 23.1323 of 14 CFR 23. The service order listed the airplane TT as 4825.9 hours. A dedicated search of all available maintenance records did not reveal any evidence that this airspeed indication system discrepancy was corrected prior to the accident.
Subsequent to the airspeed indicator write-up, the airplane successfully underwent three additional annual inspections. The first was in October 2004, and the second was in April 2006. The airplane's most recent annual inspection was accomplished in May 2007. The records indicate that at that time, the airplane had accumulated a total time in service of 4956.6 hours. All three annual inspections were conducted by the same maintenance facility that cited the October 2004 airspeed indicator discrepancy.
The 1054 weather observation at Greater Rochester International Airport (ROC), located approximately 7 miles southwest of the accident site, reported winds from 240 degrees at 9 knots, temperature of 28 degrees Celsius (C), dew point 18 degrees C, and an altimeter setting of 29.84 inches of mercury. The ambient conditions resulted in a density altitude of approximately 2,100 feet.
No air traffic control records of any communications with the accident airplane, including a request for activation of the filed VFR flight plan, were located for the accident flight. No radar returns that could be associated with the airplane were recorded by local radar facilities.
Irondequoit Bay was on the south shore of Lake Ontario. The bay measured approximately 1/2 mile in the east to west direction, and 4 miles in the north to south direction. No portion of the bay was designated as a seaplane base. The surface of the bay was at approximately 240 feet above mean seal level (msl). The accident airplane ramp was at the south end of this bay, and the Irondequoit Bay Bridge crossed the bay approximately 2 1/2 miles north of the ramp. This causeway bridge rose approximately 100 feet above the water, and was a constant height across the entire span. The terrain directly south of the bay rose approximately 100 feet above the water, and formed a shallow valley oriented north and south. The terrain to the east and west rose approximately 200 feet above the lake surface within 3/4 of a mile from the center of the bay. Trees on the surrounding terrain were estimated to be between 50 and 80 feet tall. The land on the east side of the bay was less developed than that on the west side.
The south end of the bay was located approximately half-way between the 5 and 10 mile rings that defined the ROC Class C airspace. The floor of this airspace segment was 2,100 feet msl, and the ceiling was 4,600 feet. The airspace inside the 5-mile ring extended from the surface to 4,600 feet.
WRECKAGE AND IMPACT INFORMATION
The airplane came to rest upright, approximately 47 feet north of the most prominent and also most distant ground scars. Most of the wreckage was contained in the immediate proximity of the fuselage, which was oriented along a heading of 110 degrees magnetic.
The left wing was separated from the fuselage in a mode consistent with fire-induced failure. This wing did not display any significant impact damage. Approximately the inboard third of the wing was consumed by fire, and the remaining two thirds exhibited moderate fire damage. The right wing was separated from the fuselage, also in a mode consistent with fire-induced failure. The outboard four feet of this wing were progressively bent up, to a maximum of approximately 40 degrees. The leading edge along this bend area, and the skin across the wing upper surface, exhibited crumpling consistent with a load applied in the up/aft/inboard direction. Both fuel tanks were nearly completely consumed by fire. The left aileron was intact and attached to the wing, while part of the right aileron was mechanically separated, and part was consumed by fire. Both flaps were damaged by fire. The flap actuator was in the retracted position. Aileron and flap cable continuity was established, except where the cables parted at structural breaks in the wreckage.
A small U-shaped fitting was attached to the underside of the outboard end of the right wing. A rope approximately 1/2 inch in diameter and 18 inches long was attached to this fitting. The location of this rope is consistent with it being used to assist in water handling of the airplane for docking purposes. When held in the trailing position, this rope extended aft to approximately the mid-chord position of the aileron, and aligned spanwise with the gap between the outboard end of the aileron and the wingtip fairing. The diameter of this rope was larger than the spanwise gap between the aileron and wingtip. A similar fitting was located on the corresponding position on the left wing, but no rope was observed.
Approximately 10 feet of the aft fuselage remained intact and unburned. The horizontal and vertical stabilizers, elevators, elevator trim tab and the rudder were intact. All remained affixed by all their respective hinges, moved freely, and were undamaged by fire. Control cable continuity was established, except for impact-related separations.
The two floats were located approximately 15 feet south of the main wreckage, and exhibited varying degrees of fire damage. Segments of the attach struts and control cables remained attached to the floats.
The cockpit, cabin and doors were damaged or consumed by fire. The cabin floor was severely damaged by impact forces and fire. The lower left seat frame was still attached to its seat tracks, which were still attached to the cabin floor. The right seat was separated from the seat tracks, and the seat legs and seat tracks were distorted, and partially separated from the cabin floor. No webbing from shoulder harnesses or seat belts was observed. The buckle assembly from one seat belt was latched, and also included a shoulder harness attachment stud. No evidence of a rear seat was found in the wreckage. The third partner of the airplane later confirmed that the rear seat was not installed in the airplane at the time of the accident.
No components of the stall warning system could be located in the wreckage.
The instrument panel, instruments, avionics and engine and flight controls were severely damaged by impact and fire. The barometric pressure dial in the altimeter Kollsman window was set to 29.83. Due to impact and fire damage, no other instrument or avionics readings were able to be determined. No cockpit flight or engine control positions were able to be determined.
The engine was partially attached to its mount, which was partially attached to the firewall. The engine accessories were heavily damaged by fire. Continuity of the crankshaft from the rear gears to the valves, and to the front of the crankshaft, was observed. Suction and compression were observed on all four cylinders. No damage was noted to the valves, piston domes or cylinder walls. A crack was observed in the head of the number one cylinder, near the exhaust valve seat. The carburetor was separated from the engine in a manner consistent with impact damage. The throttle, mixture and carburetor heat controls remained attached to the carburetor, but their positions were deemed to be unreliable. The oil filter element was charred, but no metallic debris was observed in the filter.
Most of the propeller was found in one piece approximately 60 feet north of the main wreckage; all attach bolts had failed in a manner consistent with overload. Both blades exhibited chordwise scarring and leading edge gouges.
MEDICAL AND PATHOLOGICAL INFORMATION
The FAA's Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, performed forensic toxicological testing on specimens from the pilot and passenger. The pilot's toxicology report stated that no carbon monoxide, cyanide, ethanol or other screened drugs were found in any samples.
The passenger's toxicology report stated that no carbon monoxide, cyanide, or ethanol were found in any samples, and that Atenolol, a blood pressure medication, was detected in the blood and urine. The passenger's autopsy, conducted by the Office of the Medical Examiner of Monroe County, New York, reported arteriosclerotic cardiovascular disease. Autopsy findings included marked atherosclerosis of native coronary vessel, thrombosis of a bypass graft, cardiomegaly, and moderate aortic atherosclerosis. The autopsy report further stated that the passenger's "arteriosclerotic cardiovascular disease is also contributory in his demise."
In a Safety Board interview, one individual who flew with the pilot in the accident airplane stated that the pilot's preflight was "thorough, cautious, and deliberate." This individual could not recall whether the pilot tested the stall warning system during that preflight inspection.
The third partner of the airplane stated that the wingtip mooring lines had been installed on the airplane for some time. When questioned by investigators, he said that when the airplane is in flight, the lines just "lay flat," and that they "do not wave or flap around."
Persons familiar with the pilots and airplane reported that the pilots used active-noise-canceling headsets. Investigators were unable to definitively determine which brand or model headsets were in the airplane at the time of the accident.
The FAA Flight Standards Service publishes "InFO" Letters intended to disseminate "valuable information for operators that should help them meet certain administrative, regulatory, or operational requirements with relatively low urgency or impact on safety." InFO Letter number 07001, dated January 5, 2007, contained the subject line "Noise Attenuation Properties of Noise-Canceling Headsets." The FAA stated that the purpose of this particular letter was to alert "operators, directors of operations (DOs), chief pilots, and flight crewmembers who may be using noise-canceling headsets of the potential for misdetection of audible alarms and other environmental sounds." In part, this InFO letter stated:
"Noise-canceling headsets are most effective over a narrow frequency range, but the specific frequencies may vary by make and model. Also, these electronically attenuated frequencies are often proprietary to the manufacturer and may not be publicly available. Therefore, it is difficult to assess any effects the headsets may have on discerning environmental sounds such as…audible alarms other than those discernible by electronic means;"
"Operators, DOs, chief pilots, and crewmembers of aircraft should evaluate their use of noise-canceling headsets. The FAA recommends sampling the available manufactured makes and models when performing such evaluations, since performance and attenuation properties vary. Evaluations should be conducted while both on the ground and in flight during normal operating conditions to ascertain if any audible alarms or other environmental sounds, or combinations thereof, can be detected while electronic noise attenuation is on and active. If any audible alarms or environmental sounds cannot be discerned, operators should elect to find other solutions to discern such alarms or sounds, or discontinue the use of noise-canceling headsets."
The April 2007 weight and balance records for the airplane indicated an empty weight of 1645.8 pounds, and an empty weight center of gravity (CG) of 40.35 inches aft of the datum line. The Kenmore STC SA584NW designated an increase in the maximum takeoff weight from 2,220 to 2,350 pounds, and extrapolated the forward and aft CG limit lines linearly to the 2,350 pound weight line.
The cabin contents were examined in an effort to estimate the takeoff weight of the airplane. In addition to the clothing, personal effects, and flight gear, a number of unopened beverage containers were found in the cabin area. These beverages were inventoried, and estimated to weigh 52 pounds. The total estimated weight for the recovered cabin contents was 112 pounds. No indications of any restraint devices for the cabin contents were found in the wreckage. According to their respective most recent medical applications, the pilot weighed 185 pounds, and the passenger weighed 209 pounds. According to the third partner of the accident airplane, fuel was typically purchased at local automobile service stations and transported to the airplane in small containers. No records of the takeoff fuel quantity could be located.
Using the above information, and assuming a full usable fuel load of 40 gallons, the take off gross weight (TOGW) was calculated to be 2,392 pounds, with a CG of 42.19 inches. The same calculations with 30 gallons of fuel yielded a TOGW of 2,332 pounds, and a CG of 42.04 inches, and calculations with 20 gallons of fuel yielded a TOGW of 2,272 pounds, and a CG of 41.89 inches. Although the highest weight exceeded the maximum certificated takeoff weight, the CG value remained within a CG envelope that was linearly extrapolated to the weight. The lower weights and corresponding CG values were within the certificated weight and balance envelope. In all three cases, the estimated CG values were closer to the respective forward limits than to the aft limits.
The Kenmore STC SA584NW did not include any information regarding changes to the airplane performance, nor did it state that performance was not affected. No records that documented any airplane performance information such as takeoff distances, speeds, or fuel consumption, could be located for the accident airplane's airframe, engine and propeller combination.
The POH supplement for the 1978 Cessna 172N Floatplane specified a Lycoming O-320, 160 horsepower (hp) engine, whereas the accident airplane was equipped with a Lycoming O-360, 180 hp engine. According to the supplement, at 4,000 feet and 75% power, the airplane would cruise at 95 knots, and have a fuel consumption rate of approximately 8 gallons per hour (gph). Cessna performance information for a Cessna 172Q equipped with Lycoming O-360, 180 hp engine, indicates that the fuel consumption rate at 4,000 feet and 72% power would be approximately 10 gph.
According to the POH supplement, a float equipped C-172N weighing 2220 pounds would have a zero-bank stall speed of 42 knots indicated air speed (KIAS) and 48 knots calibrated air speed (KCAS). These values would increase to 45 KIAS and 52 KCAS in a 30 degree bank. Aerodynamic calculations indicate that for the same airplane weighing 2400 pounds, the stall speeds would each increase approximately 2 knots.
On June 17, 2006, the pilot and passenger of this accident were involved in another accident when their Taylorcraft DC-65 collided with trees shortly after takeoff. The Safety Board cited the probable cause of this accident as "an uncontrolled descent into trees and terrain after takeoff, for undetermined reasons." In addition, the Safety Board determined that "the airplane's gross weight at the time of the accident was greater than the maximum allowable gross weight for the airplane."