LONG GROVE, IL, USA
N733XS
CESSNA 172N
A COMPUTER FLIGHT PLANNING PROGRAM PRINTOUT FOUND IN THE WRECKAGE SHOWED AN ESTIMATED 3.5 HRS EN ROUTE, WITH A 4.7 HR TOTAL RANGE. THE PILOTS DEVIATED FROM THE PLANNED DUE TO SEVERE THUNDERSTORM ACTIVITY IN THE AREA. AFTER 3 HRS 51 MIN OF FLIGHT, APPROX 7 MI FROM THE DESTINATION AIRPORT, THE ENGINE LOST POWER. THE AIRPLANE COLLIDED WITH POWER LINES DURING THE FORCED LANDING, AND CAME TO REST INVERTED IN A CORN FIELD. POSTACCIDENT EXAMINATION REVEALED NO EVIDENCE OF USEABLE FUEL IN THE FUEL SYSTEM. THERE WAS NO EVIDENCE OF PREIMPACT MECHANICAL MALFUNCTION. THE AIRPLANE WAS EQUIPPED WITH A 180 HP ENGINE (ORIGINAL EQUIPMENT WAS A 160 HP ENGINE) IN ACCORDANCE WITH STC SA703GL. THE STC DOCUMENTATION INDICATED THERE WAS 'NO CHANGE' TO THE PERFORMANCE SECTION OF THE AIRPLANE FLIGHT MANUAL. THE COMPUTER PROGRAM FUEL CONSUMPTION PERTAINED TO THE 160 HP ENGINE, AND SHOWED A FUEL CONSUMPTION OF 8.8 GPH. THE POH FOR A CESSNA 172Q (180 HP ENGINE) INDICATES THAT A FUEL CONSUMPTION RATE OF 10.0 GPH WAS MORE REALISTIC.
HISTORY OF FLIGHT On July 23, 1993, at 0656 central daylight time, a Cessna 172N, N733XS, operated as a rental aircraft by Kansas Air Center, Inc., experienced a loss of engine power and made a forced landing while en route to Palwaukee Airport (PWK), Wheeling, Illinois. The airplane was damaged beyond economical repair when it struck power lines and came to rest inverted in a cornfield in Long Grove, Illinois. The private pilot, commercial pilot/flight instructor and two passengers received serious injuries. Visual meteorological conditions prevailed, the flight operated on an IFR flight plan. The flight operated under 14 CFR Part 91 and originated from Manhattan, Kansas, approximately 0305. Postaccident interviews revealed the four friends planned the trip to Wheeling, Illinois to attend the wedding of another friend. The certificated flight instructor (CFI) arranged the airplane rental through the fixed base operator (FBO) where he was employed. The private pilot stated they amended their original planned departure time from 0800 to 0230 because of convective SIGMETs in effect for their route of flight. They expressed concern that the weather would get worse as the day continued. Weather data and AFSS transcripts are appended. The airplane departed Manhattan about 0305 and picked up their clearance from Kansas City Air Route Traffic Control Center (ARTCC) when airborne. Air Traffic Control (ATC) records and statements indicate the flight proceeded routinely for more than two hours. At 0523 the Peoria Radar Approach Controller asked if the pilots were aware of the weather along their route of flight. The pilot requested an update, and the controller advised "...it's pretty solid...all the way to Peoria. If you want to go around it you're gonna have to go well to the east." The pilot requested and received radar vectors with reference to the severe weather. At 0536 the pilot contacted ATC and stated he was "...doing some number crunching..." and wanted to land at Peoria. The radar controller responded: "This isn't a real good place to land right now...how about Bloomington?" (The controller's written statement indicated "...the intensity of the rain showers at the airport was increasing and there was a good deal of lightning in the area.") The pilot accepted Bloomington as an alternate. At 0538 the controller offered the pilot "...just a suggestion, but if you've got enough fuel to get to Palwaukee, you might think about pressing on...once you get around the east northeast side there you're...probably in good shape. If you wait it's just...more of this stuff coming in from the west...you still want to land Bloomington let me know...that won't be a problem either." The pilot elected to continue toward Palwaukee, and requested a direct routing, adding "...I've only got four and a half hours of gas and I'm into my third right now." At 0542 the controller issued a clearance which turned the airplane northbound toward Palwaukee. At 0549 the pilot received clearance to Palwaukee via preferential routing. The flight proceeded uneventfully. At 0634, Chicago-O'Hare's Terminal Radar Approach Control (TRACON) told the pilot to "...expect the ILS one six approach to Palwaukee..." The pilot acknowledged and accepted radar vectors to the approach. At 0640 the pilot contacted the TRACON controller to request "...any chance we can get a little more direct to Palwaukee?" The controller responded "...sure. Descend and maintain three thousand. As soon as you're a little lower I'll get you closer. They're using Runway Fourteen Right today at O'Hare." (See maps, appended.) At 0650 the TRACON controller instructed the pilot to descend and maintain two thousand seven hundred. The pilot responded "...down to two seven...Ah, three xray sierra, I need direct to the airport, my engine's running rough." At 0651 the pilot reported the engine had lost power completely, and he needed "anything that's close." At 0653, the pilot reported the airplane was at one thousand five hundred feet, and they could not make it to Palwaukee. He told the controller he was going to attempt a forced landing in a field, and requested "Send me everything you got." There were no further transmissions from the accident airplane. Postaccident interviews revealed the CFI sat in the right front seat and handled most of the radio communications. The private pilot occupied the left front seat, and manipulated the flight controls throughout most of the flight. The pilots wore headsets and used an intercom system for en route communications. The rear seat passengers reported they were aware of the thunderstorm activity, but received no indication from the pilots of additional concerns during the flight. One passenger stated: "It seemed almost like it ran out of gas. At one point when I looked up at the (fuel) gauges, it looked pretty low to me, but we were pretty close. Shortly after that (the CFI) told us we were 7 miles from Palwaukee." He reported as they began to descend the engine began to sputter. He reported the pilots pushed a button or lever in the front of the plane but were unable to regain engine power. He indicated when they realized they could not reach the airport they selected the corn field for a forced landing. Both passengers reported as the airplane glided toward the corn field for the emergency landing, they heard the private pilot yell that they were going to hit the wires. They described a white flash of electricity as the airplane struck the power lines. The airplane pitched forward and fell to the ground, coming to rest inverted. A witness ran to the airplane immediately to assist until authorities arrived. OTHER DAMAGE There was damage to a section of power lines and crops (corn) as a result of the airplane accident. AIRCRAFT INFORMATION The Cessna 172N (Skyhawk) was originally equipped with a Lycoming O-320-H2AD engine. The accident airplane had been altered in accordance with Supplemental Type Certificate (STC) SA703GL, and was equipped with a Lycoming O-360-A4A engine at the time of the accident. Copies of the FAA Form 337 (Major Repair and Alteration), STC SA703GL, Supplemental Airplane Flight Manual, excerpts from 172N and 172Q Pilot's Operating Handbooks (POH), and other associated documentation are appended. METEOROLOGICAL INFORMATION Convective SIGMET (21C) in effect for the states of Iowa, Missouri, and Nebraska indicated an area of severe thunderstorms moving from 280 degrees at 20 knots. The SIGMET stated tops above 45,000 feet, hail to 1 inch, and wind gusts to 50 knots were possible. The pilots received a complete weather briefing, and obtained up to date weather information prior to their departure. They reportedly altered their time of departure in an attempt to avoid the thunderstorms. Weather information is appended. WRECKAGE/IMPACT INFORMATION Witnesses reported they did not hear any engine noise as the airplane flew low overhead toward the corn field for the emergency landing. They stated the airplane was descending overhead on a southerly heading when it struck power lines located along the north boundary of the field, approximately 31 feet above the ground. The airplane pitched forward and fell to the ground. Photographs are appended. The airplane initially impacted the ground in a steep nose down, right wing low attitude, approximately 107 feet south of the power lines. It came to rest inverted in 5 to 7 foot tall corn, about 132 feet south of the power lines. The airplane was aligned on a 010 degree heading, and rested on the top of the wings, the cabin roof, and the vertical stabilizer. The nose section of the aircraft was crushed and bent left, up and aft. The engine and accessories were almost completely separated from the firewall. The propeller exhibited slight bending. The tail section was buckled aft of the baggage compartment and the vertical stabilizer and rudder were wrinkled. The left main landing gear and nose gear had separated from the airframe, and were located south and north of the wreckage, respectively. The broken power line cable displayed evidence of paint transfer. The right wing was wrinkled and the leading edge was crushed aft to the wing strut attach point, with more extensive damage toward the wing tip. The left wing was wrinkled and leading edge exhibited minimal crush. The wing flaps were in the retracted position, consistent with cockpit indications and pilot statement. Postaccident investigation revealed no evidence of useable fuel in the fuel system. An engine teardown revealed no evidence of preimpact mechanical malfunction. ADDITIONAL INFORMATION Local authorities reported the private pilot told them he didn't know what happened, but "...we couldn't have run out of gas." He stated their preflight planning indicated they should have had about one hour of fuel remaining when the engine lost power. He told the Deputy Sheriff the flight had gone as planned except for some radar vectors to avoid thunderstorm activity. This is consistent with ATC records, appended. A "Flitesoft" computer printout with flight planning information pertinent to the accident flight was located in the wreckage. The printout indicated the flight was planned for an altitude of 6,000 feet, at 70% BHP. The performance summary estimated 3.5 hours time en route, at an average fuel consumption rate of 8.8 gallons per hour (GPH). It estimated 1.2 hours of fuel remaining upon arrival, for an estimated total range of 4.7 hours. Records indicate the accident airplane departed Manhattan, Kansas with full fuel tanks (43 gallons, 40 gallons of which are useable). Aircraft records and Hobbs meter readings indicated the elapsed time from engine start to shutdown was 4.0 hours. The computer printout data corresponded to the data in the POH for the Cessna 172N utilizing the 160 HP engine, with adjustments to include fuel consumption during the climb. There was no fuel consumption data specific to the 180 HP engine on the 172N available to the pilots during their preflight or en route planning. Examination of the Cessna 172Q (originally equipped with the 180 HP engine) POH, indicated an estimated fuel consumption rate of 10 GPH was more realistic. Excerpts from the 172N POH and the 172Q POH are appended. The Supplemental AFM, available to the pilots for planning purposes, listed the "Normal Procedures" and "Performance" sections as having "No Change." An amended power setting chart, marked "DO NOT REMOVE FROM N733XS," was appended to the POH, but contained no fuel consumption data. A review of the Federal Aviation Administration (FAA) Civil Air Regulations (CAR), Part 3, revealed fuel consumption data was not required to be included in either the "Procedures" or "Performance" sections. Excerpts from FAA CAR 3 are appended.
THE PILOT-IN-COMMAND'S FAILURE TO REFUEL THE AIRPLANE PRIOR TO FUEL EXHAUSTION. RELATED FACTORS TO THE ACCIDENT WERE: INADEQUATE CERTIFICATION/APPROVAL OF THE STC BY THE FAA, INADEQUATE PERFORMANCE DATA, AND UNAVAILABLE FUEL CONSUMPTION INFORMATION.
Source: NTSB Aviation Accident Database
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