N734BLCessna 172N · 1977

On October 12, 2008, about 1050 eastern daylight time, a Cessna 172N, N734BL, was substantially damaged during a forced landing in an athletic field, shortly after takeoff from Kissimmee Gateway Airport (ISM), Orlando, Florida. The certificated private pilot/owner, the sole occupant, was seriously injured. The personal flight was operated under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed for the flight, and no flight plan was filed.

According to the pilot, he stored the airplane outside at ISM. The pilot stated that although he did not fly the airplane much in the year prior to the accident, he occasionally ran the engine on the ground, and he believed that the airplane had not been flown in the 10 months preceding the day prior to the accident. Two days before the accident, the pilot asked a maintenance technician to place a fuel order to fill the airplane, and the airplane was fueled with 32 gallons that evening. The next day, in the late morning, the pilot arrived to "test-fly" the airplane, in preparation for an upcoming cross-country flight.

When the pilot arrived at ISM, the technician who placed the fuel order told the pilot that subsequent to the refueling, he drained a "significant amount" of water from the tanks and the fuel strainer. The pilot stated that he conducted a preflight inspection of the airplane, which included sampling fuel from each of the two fuel tank sump drains. He did not observe any water in those samples. He also drained some fuel from the fuel strainer, but he did not capture that fuel. After the preflight, the pilot conducted approximately five takeoffs and landings at ISM. He said that they were uneventful, the airplane "ran fine," and the flight duration was about 1/2 hour. The pilot then parked the airplane, and left the airport.

The day of the accident, the pilot returned to the airport with the intention of conducting a cross-country flight. He conducted another preflight inspection; which again included sampling fuel from the two fuel tank sump drains, and again he did not observe any water in those samples. He also drained some fuel from the fuel strainer, but again he did not capture that fuel.

According to the pilot, he intended to fly the airplane to Huntsville, Alabama. According to Lockheed Martin Flight Services (LM), the pilot did not contact LM for any flight or weather briefing information, or to file a flight plan.

According to witnesses at the airport, the airplane began its takeoff roll near the threshold of runway 6, and became airborne prior to crossing runway 15/33. Shortly thereafter, the airplane began to lose altitude, and drift southeast of the runway. At some point in the sequence, the pilot declared an emergency on the ISM air traffic control tower (ATCT) radio frequency. One witness reported that the airplane then "banked sharply to the left," and descended rapidly to the ground. Witnesses near the accident site reported that the airplane appeared to be attempting to land on the athletic field, but that it struck a sports goal post. Witness reports did not agree on whether the airplane struck the goal post while airborne or after touchdown, and some witnesses reported that the airplane bounced during the landing. The airplane came to rest upright, on the athletic field, approximately 1/4 mile beyond the departure end of runway 6.

Federal Aviation Administration (FAA) records indicated that the pilot held a private pilot certificate with an airplane single-engine land rating. His most recent FAA third-class medical certificate was issued in October 2006, and he reported 1,200 total hours of flight experience at that time. The pilot’s logbook registered 12 flights and a total of 10.7 flight hours for 2006; however three of the entries did not include associated flight times. The pilot’s logbook registered one flight in 2007. The logbook indicated that the flight occurred on January 1, 2007, and lasted 1.5 hours. All pilot logbook entries for 2006 and 2007 indicated that the flights were conducted in the accident airplane. The pilot’s logbook did not contain any entries for 2008.

The accident airplane was manufactured in 1977, and was equipped with a Lycoming O-320 H2AD piston engine. The airplane was first registered to the pilot in 1984. The most recent annual inspection was completed 2 days prior to the accident. At the time of the accident, the tachometer registered 886.9 hours, and the hour meter registered 830.1 hours. Comparison of these values with values recorded in the maintenance records indicated that the airplane had been operated 0.7 hours between the most recent annual inspection and the accident.

The ISM 1950 recorded meteorological information for October 9 reported light rain. The ISM 1850 observation for October 10 also reported light rain, and the 1950 observation reported that the rain ended about 1915. No rain was reported at ISM on October 11 or 12. The 1050 special weather observation at ISM on the day of the accident (October 12) reported winds from 010 degrees at 10 knots, scattered clouds at 1,800 feet, broken cloud layers at 2,400 and 3,000 feet, 10 miles visibility, temperature 28 degrees C, dew point 23 degrees C, and an altimeter setting of 30.10 inches of mercury.

A review of the communications between the pilot and the controllers in the ISM air traffic control tower revealed that about 1044, the pilot contacted ground control for his initial taxi clearance. The pilot was instructed to taxi to runway 6, with instructions to hold short for clearance to cross the runway. About 2 minutes later, the ground controller cleared him to cross runway 6 with "no delay." About 1050, the pilot informed the local controller that he was ready for departure, and the controller instructed him to "taxi up to and hold short of runway 6," which the pilot acknowledged. About 1 minute later, the controller cleared the pilot for takeoff. About 90 seconds after that, the pilot declared an emergency, did not elucidate, and did not finish his sentence. The local controller replied 5 seconds later with "who has the emergency," but he did not receive a reply. About 1053, the controller transmitted "november seven three four, Kissimmee tower, can you hear me sir," but no other transmissions were received from the airplane. About 30 seconds after that, the local controller informed another airplane on the ground that the accident airplane had crashed,

Kissimmee Gateway Airport was configured with two runways, 6/24 and 15/33. Runway 6/24 was 5,000 feet long and 150 feet wide. Runway 15/33 crossed 6/24 at approximately the midpoint of 6/24. Airport elevation was listed as 82 feet above mean sea level (msl).

Documentation provided by the FAA inspector who responded to the accident revealed that the airplane came to rest upright on a southerly heading, with a pitch attitude of approximately 30 degrees nose down. The nose landing gear and lower cowl were crushed up and aft. The main landing gear struts and wheel assemblies were intact, but the left gear strut was deformed approximately 20 degrees up from its normal orientation. The windshield was fractured and separated from the airplane, and the right horizontal stabilizer was crushed and deformed down and aft. Both wings exhibited crumpling of the upper inboard skins, and both were rotated approximately 5 degrees trailing edge down, relative to their normal alignment with the fuselage. Witnesses, first responders, and airplane recovery personnel all reported that fuel was leaking from the left wing after the accident. The inspector reported that he found the fuel selector handle set to the "both" position, and subsequently moved it to the "off" position. There was no fire. Recovery personnel transported the airplane back to ISM, and covered it with a tarp.

Postaccident examination of the airplane was accomplished by FAA, Cessna and Lycoming personnel on October 15, 2008. The exterior paint was chalked, flaked or missing on much of the skin. The external face of the upper skin panel that covered the left fuel tank was painted with primer only. One propeller blade was bent aft, and the other was undamaged. No preimpact mechanical anomalies that would have prevented the production of power were noted with the engine. The engine was rotated by hand, and thumb compression and spark were verified at each cylinder.

Flight control cable continuity was confirmed from the cockpit controls to the respective flight control surfaces. The only discontinuity noted was the separation of one flap cable in the fuselage-wing carry-through section. The separation was consistent with tensile overload failure.

Each fuel tank cap was in its locked position in its respective filler neck. The left cap was a loose fit, and a 0.028 inch feeler gauge was able to be inserted between the cap gasket and its seat. No anomalies with the fit of the right cap in the filler neck were noted. No determinations of the gaskets' condition, expiration date(s), or nominal shelf life, was made.

The left fuel tank was empty at the time of the examination. Fuel samples were obtained from the right fuel tank, the fuel strainer, and the carburetor. According to the Cessna representative, each of these samples contained "several ounces of a yellowish liquid with dirt deposits." Blue liquid was observed floating on top of the yellowish liquid, and a water-indicating paste indicated positive results for the presence of water in the yellowish liquid.

Airplane Maintenance Records

The maintenance records that were provided to the investigation did not provide a continuous history of the airplane. Two bound logbooks, one each for the airframe and the engine, contained notations that they were "opened [started] on 8/2008." A separate binder contained an incomplete assortment of maintenance records for the airframe and engine prior to 2008. The records indicated that the left wing was replaced in July 1986. No records were found for the period from 1988 to 2003. A document from September 2003 stated that "rusty fuel tank cover screws" were removed and replaced, and it also contained a handwritten annotation from the technician to the owner that stated "I need to make up that patch on the L[ef]t wing."

The maintenance records indicated that at the time of an annual inspection in September 2003, the tachometer registered 847 hours. In January 2005, the tachometer reading was 866.9 hours, and in January 2006, the tachometer reading was 881.3 hours.

Aircraft and engine logbook entries dated October 10, 2008 indicated that the airframe and engine were inspected in accordance with an annual inspection, and were considered to be in an airworthy condition. These entries indicated a tachometer time of 886.2 hours, and an airplane total time in service of 1458.1 hours. The aircraft logbook indicated that a number of components were installed or replaced in conjunction with the annual inspection, including the pitot tube, airspeed indicator, emergency locator transmitter (ELT) battery, aircraft battery, aileron control rod, all tires and tubes, and multiple fairings and antennae. The engine logbook annual inspection entry indicated that the engine had accumulated 39.2 hours in service since a "top overhaul," but no record of that overhaul could be located.

Airplane Fuel System and Manufacturer's Guidance

The airplane was equipped with two fuel tanks, one in each wing. Total fuel capacity was 43 gallons, of which 40 gallons were usable. Each fuel tank was equipped with a sump drain located at the inboard aft corner of the tank, and a fuel strainer was installed on the firewall in the engine compartment. The fuel selector valve had four settings: left tank, right tank, both tanks, and off.

The preflight inspection procedure listed in the Cessna 172N Pilots Operating Handbook (POH) contained two entries, one each for the right and left wing, which stated: "Before first flight of the day, and after each refueling, use sampler cup and drain small quantity of fuel from fuel tank sump quick-drain valve to check for water, sediment and proper fuel grade." The POH procedure stated the following under the "Nose" section: "Before first flight of the day, and after each refueling, pull out strainer drain knob for about four seconds to clear fuel strainer of possible water and sediment...If water is observed, the fuel system may contain additional water, and further draining of the system at the strainer, fuel tank sumps, and fuel selector valve drain plug will be necessary."

In 1980 the manufacturer issued Service Information Letter (SIL) SE80-87, applicable to "All Cessna Single Engine Aircraft," and with the subject line of "Fuel Contamination." The SIL stated that "before the first flight of the day and after each refueling, use a clear sampling cup and drain a cupful of fuel from the fuel tank sump quick drain valve to determine if contaminants are present," and "If contamination is detected continue draining from all fuel drain points, including drain plugs, until all contamination has been removed." The SIL also stated "Do not fly the aircraft with contaminated...fuel."

In 1982, the manufacturer issued SIL SE82-36, applicable to all Cessna single engine airplanes, which stressed the importance of routine fuel system inspection and maintenance. The Owner Advisory attached to the SIL stated that persons conducting airplane preflight inspections should "Gently move the wings and/or lower the tail to the ground (on nose gear aircraft) to move the contaminants to the sampling points and assure that they are drained from the fuel system," and to "Take repeated samples from all drain points until all contamination has been removed." The Owner Advisory attached to SE82-36 stated "Make certain fuel caps are secure and sealing properly at all times (reference Service Information Letter SE82-34)."

The 1982 manufacturer's SIL SE82-34 stated that "An important part of every pre-flight inspection is to...make certain the fuel filler cap is not only secured but is sealing properly...because a leaking fuel filler cap may allow water...to enter the fuel system." The SIL recommended that "Owners and Operators add the following checks to their normal pre-flight activity in order to detect and preclude "fuel contamination, including inspecting the fuel cap seals for cracking, distortion, and general condition which might prevent sealing," and "ensuring that the [fuel filler cap adapter] sealing face is not distorted, scratched, marred or in such a condition as to prevent the cap from sealing." The SIL also provided explicit guidance to conduct a leak check of the tank cap seal.

In 2000, the FAA issued Airworthiness Directive (AD) 2000-06-01, which applied to many Cessna airplanes, including the accident airplane. The AD had an effective date of May 5, 2000, and required measuring the visible length of the standpipe in the fuel strainer, and replacing any fuel strainer assembly that did not have the correct standpipe length. The actions specified by the AD were intended to prevent foreign material from entering the fuel system and engine, which the FAA stated "could result in loss of engine power or complete engine stoppage during flight." The October 2008 AD compliance record for the airplane contained the handwritten annotation "N/A, Parts not installed" next to the entry for AD 2000-06-01. Examination revealed that the standpipe height was 1.66 inches, which confirmed that the standpipe was in compliance with the manufacturer's design specifications.

Fuel Records

According to information provided by the fixed base operator (FBO) at ISM, the accident airplane was fueled with 32 gallons of avgas on October 10, 2008. Fuel quality records provided by the FBO indicated that prior to the accident, the fuel complied with all tested standards, including contaminant levels.

After the accident, the pilot told investigators that he "typically" obtained "some water" when he sumped the left fuel tank. He quantified it as approximately a 1-inch column of water in the 3/4 inch-diameter sample container.

The pilot also stated that he believed that the fuel cap gaskets were replaced during a recent annual inspection. A search of the available maintenance records indicated that two fuel cap gaskets were purchased for the airplane in December 2002, but that the documentation did not explicitly state whether the gaskets were installed. As of the date of the accident, the gaskets were approximately 6 years old, and they would have accumulated a total time in service of 40 hours if they were installed shortly after their purchase.