Factual Reports Shows A Full Inspection Of The Fuel System May Not Have Been Performed

The NTSB has released its factual report for an accident which occurred July 23rd, 2010, in which four of the five people aboard a Cessna 206 were fatally injured.

The airplane was ditched in Lake Michigan about 5 miles west of Ludington, Michigan, after a loss of engine power. The airplane was owned and operated by the pilot as a personal flight under 14 Code of Federal Regulations Part 91. It departed the Gratiot Community Airport (AMN), Alma, Michigan, at 0850 local time and was en route to Rochester International Airport (RST), Rochester, Minnesota. The single-engine airplane was over Lake Michigan at 10,000 feet above mean sea level (msl) when the engine lost power. The pilot reversed course but was unable to reach the shore, and he ditched the airplane. The pilot survived and was rescued by a fishing boat about 38 minutes later. The pilot rated passenger and three other passengers did not survive. Visual meteorological conditions prevailed at the time of the accident. An instrument flight rules (IFR) flight plan was activated.

On July 23, 2010, about 0659, the pilot rated passenger called the Princeton Automated Flight Service Station to obtain a weather brief and to file an IFR flight plan. The briefer informed him that there was an airmen's meteorological information (AIRMET) for IFR conditions for the entire route of flight that was valid until about 1100 - 1400. There was a Convective significant meteorological information (SIGMET) to the south that paralleled the route of flight. The briefer reported that the winds aloft were from 260 degrees at 41 knots at 9,000 feet, and 270 degrees at 35 knots at 12,000 feet. The pilot rated passenger filed the flight plan and identified the flight as a "lifeguard" flight.

The pilot reported that the purpose of the flight was to take one of the passengers to the Mayo Clinic in Rochester, Minnesota, for medical treatments. The flight was a personal flight and was not associated with a charity organization. The patient and his wife were seated in the aft seats, seats 5 and 6. The patient's doctor was sitting in the middle row on the left in seat 3. The pilot was in the left front seat and the pilot rated passenger was in the right front seat, seat 2. The fuel tanks were filled to capacity the night before the flight. The pilot reported that after climbing to 10,000 feet msl, he leaned the fuel mixture to approximately 14 gallons per hour (gph).

The pilot reported that all of the instrument readings were within normal limits as they crossed the shore near Ludington, Michigan. The head winds were about 40 knots "directly on the nose." Near mid-point over the lake (about 24 statute miles from the shoreline), the engine began to misfire and lose power, with the fuel flow dropping to about 11 gph. The pilot attempted to regain power by pushing in the mixture control to full rich but without effect. About 1005, the pilot contacted the Minneapolis Air Route Traffic Control Center (ARTCC) and reported that the airplane was losing power. He reversed course toward the Michigan shoreline. The fuel flow dropped to about 8 gph. The pilot switched fuel tanks and adjusted the mixture control in and out to try to regain power. He attempted to prime the engine but that had no effect. He reported that he turned on the high boost pump and got a short burst of power for about 30 - 45 seconds, but then the engine "failed completely."

The airplane descended through a cloud layer. About 1012, the airplane was about 12 miles from Ludington and about 2,300 feet above mean sea level (msl) and the airplane was still in the clouds. The surface weather at Ludington indicated that the cloud bases were at 1,800 feet msl. The pilot reported that they had a few minutes before water impact after breaking out of the clouds, so he had everyone don and inflate their life vests. Before impact, the pilot unlatched the pilot's door on the left side of the airplane, and he had the front door of the rear cargo door unlatched. The pilot reported that he did not lower the flaps since the cargo doors would not open if the flaps were extended.

The pilot reported that when he ditched the airplane, either the tail or the landing gear hit the water as he pulled up to go over a swell. The airplane pitched forward, flipped over on its back, and began to fill with water. The pilot unbuckled his seat belt and shoulder harness, fell a short distance, pushed the door open, and got out. He reported that the airplane was sinking rapidly. He saw the right seat passenger and the doctor in the water. A wave hit the pilot and when he resurfaced "everything was gone." He kept yelling but got no response. He eventually started to swim toward the shoreline. About 30 minutes later a US Coast Guard helicopter flew over him but they did not spot him. A few minutes later a fishing boat spotted him and rescued him from the water. He was transferred to a Coast Guard vessel and was taken to shore.

Using side scanning sonar, the Michigan State Police Dive Team located the airplane in about 173 feet of water on July 30. The dive team recovered all the bodies, with the last body being recovered on the morning of August 1, 2010.

The airplane was found resting on its main landing gear on the sandy lake bottom. The airframe and engine were separated by the water impact. Both were raised to the surface by a local commercial recovery service on August 1, 2010. The airframe and engine were taken to a local facility where the National Transportation Safety Board (NTSB) conducted its on-site investigation.

The airplane's maintenance logbooks indicated that four different inspection authorization (IA) mechanics had conducted the required annual maintenance inspections on the airplane within the last ten years. The logbooks indicated that the same IA mechanic had performed the last three annual maintenance inspections. On September 27, 2007, the IA mechanic performed his first annual maintenance inspection of the airplane. The total airframe time was 3,893.4 hours. His second annual inspection of the airplane was conducted on October 1, 2008, and the airplane had a total time of 3,908.1 hours. The last annual maintenance inspection was conducted on November 5, 2009, and it had a total time of 3,938.0 hours. At the time of the accident, the airplane had flown 7.5 hours since the last inspection and had a total time of 3,945.5 hours.

FAA inspectors interviewed the IA mechanic concerning the annual maintenance inspections he had conducted on the accident airplane. According to the FAA inspectors, the IA mechanic reported that he used the inspection checklists provided by the pilot/owner in order to conduct the annual maintenance inspections. The pilot/owner provided the IA mechanic with the Cessna Service Manual for "Stationair Series, Skywagon 206 Series and Super Skylane Series, 1969 thru 1971." The service manual indicated the items that needed to be inspected during a 50-hour inspection and 100-hour (annual) inspection. In the section of the checklist covering the "Engine Compartment," Item 29 states that the "Fuel-air control unit screen" is required to be checked during every 100-hour inspection. In the section of the checklist covering the "Fuel System," Item 2 states that the "Fuel strainer screen and bowl" is required to be checked during every 100-hour inspection.

File Photo

The Emergency Procedure section of the airplane Owner's Manual provides the procedures for "Ditching." The ditching procedures state:

• Plan approach into wind if winds are high and seas are heavy. With heavy swells and light wind, land parallel to swells.
• Approach with flaps 40 degrees and sufficient power for a 300 ft./min rate of descent at 75 MPH. 
• Unlatch the cabin door.
• Maintain a continuous descent until touchdown in level attitude. Avoid a landing flare because of difficulty in judging airplane height over a water surface.
• Place folded coat or cushion if front of face at time of touchdown.
• Evacuate airplane through cabin doors. If necessary, open window to flood cabin compartment for equalizing pressure so that door can be opened.
• Inflate life vests and raft (if available) after evacuation of cabin.

The airplane's Owner's Manual states that when conducting the "Before Entering the Airplane" checklist during the preflight, it is important check the cargo doors are securely latched and locked. An "IMPORTANT" note states:

"The cargo doors must be fully closed and latched before operating the electric wing flaps. A switch in the upper door sill of the front cargo door interrupts the wing flap electrical circuit when the front door is opened or removed, thus preventing the flaps being lowered with possible damage to the cargo door or wing flaps when the cargo door is open."

The Owner's Manual section titled "Cargo Door Emergency Exit" states the following information:

"If it is necessary to use the cargo door as an emergency exit and the wing flaps are not extended, open the forward door and exit. If the wing flaps are extended, open the doors in accordance with the instructions shown on the placard which is mounted on the forward cargo door."

The red placard found on the front cargo door of the accident airplane stated:

• EMERGENCY EXIT OPERATIONS
• OPEN FWD CARGO DOOR AS FAR AS POSSIBLE.
• ROTATE RED LEVER IN REAR CARGO DOOR FWD.
• FORCE REAR CARGO DOOR FULL OPEN.

The engine was sent to the manufacturer for inspection and operational testing. The engine was put on a test stand and run. The engine experienced a normal start. The engine RPM was advanced to 1,200 rpm and held for 5 minutes to stabilize; 1,600 rpm and held for 5 minutes to stabilize; 2,450 rpm and held for 5 minutes to stabilize; and at full throttle and held for 5 minutes to stabilize. The throttle was rapidly advanced from idle to full throttle six times and it accelerated and decelerated without hesitation or interruption in power. It produced rated horsepower.

The NTSB Materials Laboratory examined the debris found in the fuel metering assembly's fuel inlet screen. The examination of the material removed from the filter revealed several categories of materials present within the mixture. The materials present included: 1) cellulosic material similar to wood and sawdust; 2) non-metallic amber-colored flakes similar to varnish or shellac; 3) thin, ribbon-like metallic shavings; 4) white flakes similar to paint; 5) granular particulates similar to sand or dirt; and 6) fibers similar to fabric and glass fibers.

NTSB Public Affairs Officer Keith Holloway said the probable cause report is still pending.

FMI: www.ntsb.gov