NTSB Factual Report

HISTORY OF FLIGHT

On September 24, 2006, about 1435 central daylight time, a Cessna 182Q equipped with amphibious floats, N97435, piloted by a private pilot, was substantially damaged when it nosed over upon landing on Staples Lake near Cumberland, Wisconsin. Efforts to rescue the pilot were not successful. The personal flight was being conducted under 14 CFR Part 91 without a flight plan. Visual meteorological conditions prevailed at the time of the accident. The flight departed South St. Paul Airport - Fleming Field.

A witness reported that the airplane circled the lake and initially appeared to be approaching a paved landing strip near the lake. However, the airplane turned to the south and approached the lake from the east. He reported that the wheels were down at that time. He stated that the pilot's approach appeared to be "level and very routine." He reported that when the airplane contacted the water surface the floats "appeared to drag" and the airplane nosed over.

This witness stated that he entered the water and attempted to gain access the cabin. He reported that the windshield seemed to be intact. He noted, "After locating what I am sure was the [door] latch I made several attempts to open it. With both feet pushing against the plane and pulling with all I could, I was unable to budge it." His attempts to rescue the pilot were unsuccessful.

A second witness reported that she heard a plane fly over the lake. A few minutes later she heard what she believed to be the same airplane again. She stated that she saw the airplane approach the middle of the lake. She recalled seeing the wheels down and initially thought that it was in trouble, however, she then noticed the floats. She reported that the wind was blowing and gusting, and the lake seemed rough.

This witness stated that the airplane touched down and flipped over. She noted that the airplane floated sideways for several minutes. By the time she and her husband arrived on-scene in their pontoon boat, there were two other boats there and one man was in the water attempting to rescue the pilot.

The airplane was subsequently recovered to the lakeshore by local authorities.

PERSONNEL INFORMATION

The pilot held a private pilot certificate with single-engine land and sea airplane ratings. The certificate also included an instrument airplane rating. He held a third-class airman medical certificate issued on November 15, 2005.

The pilot's logbook was reviewed. The most recent entry was dated September 5, 2006. According to the logbook, as of that date, the pilot had accumulated 1,675 hours total flight time. Of that flight time, 614 hours were in single-engine sea airplanes. The pilot completed a flight review on September 18, 2004, in a Cessna 172XP airplane.

According to the logs, the pilot had acquired 199 hours total flight time in Cessna 182 model airplanes. For the 90-day period prior to the date of the accident, the pilot had logged 107 hours total flight time, of which 74 hours were in a Cessna 182. Within 30 days of the accident the pilot logged 11 hours, all of which were in a Cessna 182.

AIRCRAFT INFORMATION

The accident airplane was a 1979 Cessna 182Q, serial number 18267091. The airplane was powered by a 300-horsepower Continental IO-550-D (27) fuel injected engine, serial number 284371. This engine had been retrofitted into the accident aircraft under Supplemental Type Certificate (STC) SA00152WI on August 8, 2001.

Wipaire Model 3000 amphibious floats, serial numbers 30001 and 30002, were installed on the accident aircraft. Aircraft records indicated that the floats were originally installed by Wipaire under STC SA1156CH on March 17, 2001.

According to Federal Aviation Administration records, the accident pilot purchased the airplane on May 15, 2005. The records also indicated that Wipaire, the manufacturer of the floats, owned the airplane from December 1995 until March 2002. During that time, the airplane was used for research and development purposes.

Maintenance records indicated that the most recent annual inspection was completed on May 4, 2006. The records noted an aircraft total time of 3,045.1 hours, and a recording tachometer time of 466.2 hours, at the time of the inspection.

METEOROLOGICAL CONDITIONS

Conditions recorded by the Rice Lake Regional Airport (RPD) Automated Weather Observing System (AWOS), located approximately 16 miles east-southeast of the accident site, at 1435, were: Scattered clouds at 4,800 feet above ground level (agl); wind from 310 degrees at 10 knots, gusting to 16 knots; 10 miles visibility; temperature and dew point were 17 degrees and 4 degrees Celsius, respectively; altimeter was 29.93 inches of mercury.

Conditions recorded by the RPD AWOS at 1415, about 20 minutes before the accident, were: Scattered clouds at 11,000 feet agl; wind from 300 degrees at 9 knots; 10 miles visibility; temperature 17 degrees Celsius; dew point 4 degrees Celsius; and altimeter 29.93 inches of mercury.

Conditions recorded by the RPD AWOS at 1455, about 20 minutes after the accident, were: Scattered clouds at 5,000 feet agl; winds from 300 degrees variable at 8 knots, gusting to 17 knots; 10 miles visibility; temperature 17 degrees Celsius; dew point 5 degrees Celsius; altimeter 29.92 inches of mercury.

WRECKAGE AND IMPACT INFORMATION

The airplane was recovered to the southern shore of Staples Lake. The airplane was inverted and the floats were separated from the airframe at that time. Local authorities reported that the floats were separated during and following the recovery of the airplane. The coordinates of the airplane at the lake shore after recovery were 45 degrees, 29.710 minutes north latitude; 092 degrees 08.743 minutes west longitude, as determined by a handheld global positioning system receiver.

The wings, empennage, and flight controls remained attached to the airframe. The left wing lower wing skin was wrinkled and buckled from approximately mid span outboard. The outboard leading edge of the left wing was crushed aft. The left side of the fuselage was buckled in an area aft of the baggage door. Flight control continuity was confirmed. The flap control handle was at a 20-degree flap down setting. The actual flap positions were symmetric and appeared to correspond to that setting.

The propeller and spinner remained attached. Two propeller blades were bent aft approximately 20 degrees about a point near the mid span of each blade. The third propeller blade appeared undamaged.

The engine cowling was crushed inboard and upward along the bottom and sides of the assembly. The engine remained attached to the engine mount and the mount did not appear to be deformed. Engine control continuity was confirmed. Internal engine continuity was confirmed via crankshaft rotation. Compression was observed at all cylinders during crankshaft rotation. The magnetos, ignition harness and vacuum pump appeared intact. The spark plugs were removed and the appearance of each plug was consistent with normal wear.

The landing gear control handle was in the up position when viewed after recovery. The gear selector circuit breaker was in the open position. The gear pump and gear advisory circuit breakers were in the closed position.

The floats exhibited scrapes and dents. Separations of the struts and support bars were consistent in appearance with overload failures. All four wheels were in the down and locked position. Gear retraction and extension hydraulic cylinders and linkages appeared undamaged. The main and nose gear assemblies were intact.

The magnetic gear position switches and wiring harness located on the floats were examined. Continuity was observed on the gear down switches. When the gear-up switches were closed with a magnet, continuity was observed on the gear up switches. Continuity was also observed on one gear up circuit on the right float without the switch being actuated with a magnet.

Each float was equipped with a manual gear position indicator. The main gear assembly included an indictor arm and flexible cable, which protruded through a slot in the top of the float. Placards adjacent to the relief slot denoted the gear position as "Up Water" or "Down Land." The left and right manual gear indicators were visible from the left and right side pilot seats, respectively, when viewed on an exemplar Cessna 182 airplane, equipped with Wipline Model 3000 amphibious floats.

The manual gear indicator on the left float corresponded to a wheels down position when observed during the post accident examination. Removal of the indicator cover panel revealed that the indictor arm was not bent or visibly deformed. The flexible cable and red end cap were intact. The "Down Land" placard had separated from the cover.

The manual gear indicator on the right float did not protrude through the slot in the cover panel when observed after recovery of the airplane. The cover panel was intact and the "Up Water" and "Down Land" placards were present. Removal of the cover revealed that the indicator arm was intact and not visibly deformed. It was in the gear down position. The flexible cable and red cap remained attached to the arm, although the cable had moved inside the float.

The recording hour meter indicated 276.7 hours. The recording tachometer indicated 533.4 hours.

MEDICAL AND PATHOLOGICAL INFORMATION

An autopsy of the pilot was conducted at Sacred Heart Hospital, Eau Claire, Wisconsin, on September 25, 2006.

The Federal Aviation Administration Civil Aero Medical Institute (CAMI) toxicology report was negative for all substances tested.

SURVIVAL ASPECTS

The seat belts, shoulder harnesses and cabin doors were examined during the on-scene investigation. Both left and right seat belts and seat belt buckles were intact. The shoulder harnesses were also intact and remained attached to the airframe at the door post anchor points. The shoulder harness buckles were intact.

Both the left and right cabin doors remained attached to the airframe. Scrape marks and minor dents existed on the right door and door jamb in the vicinity of the handle. Authorities reported that they used a pry bar in an effort to gain access to the cabin because the doors were locked upon recovery.

Once unlocked, the doors opened and closed freely on their hinges. Movement of the interior door handles was unrestricted. The locking tabs that extended from the aft edge of the doors and into the mating door jam recesses were examined. Both extended and retracted when the door handle was moved from the locked through the closed and to the open position. Extensions of the locking tab from the door in the locked, closed and open positions were measured. These extensions corresponded to those measured on an exemplar C182 airplane. The door jam recesses appeared intact.

TESTS AND RESEARCH

The landing gear control assembly, which included the gear handle and gear position indicator lights, and the hydraulic power pack were removed and tested under supervision of the National Transportation Safety Board (NTSB).

Electrical continuity of the gear handle was confirmed. All gear position lights, and the pump operation light, illuminated when energized. The gear advisory switch illuminated and functioned properly when tested. The hydraulic power pack actuated a test hydraulic cylinder. The pump cycled properly and reached system pressures of between 440 pounds per square inch (psi) and 580 psi.

The gear advisory unit was examined. The threshold airspeed setting on the unit appeared to correspond to an arming/alert airspeed of 70 knots. The unit was unable to be tested due to water damage. The wiring harness for the gear advisory unit was inspected and electrical continuity of the harness was confirmed.

ADDITIONAL INFORMATION

The Wipaire amphibious floats were equipped with a retractable landing gear system to allow for runway operations. Each float included a main landing gear located approximately mid-length of the float, and a nose gear, which extended from the front of the float.

Gear retraction and extension was accomplished by hydraulic pressure provided by a reversible electric pump installed in the rear fuselage, aft of the baggage compartment. According to the service manual provided by Wipaire, the hydraulic system operates at between 500 psi and 700 psi.

The pilot controls gear retraction or extension by using a lever located on the instrument panel. Adjacent to the gear control lever is a cluster of eight gear position indicator lights. Four green lights are normally illuminated when the landing gear is down, such as in the event of a runway landing. Four blue lights are normally illuminated when the landing gear is up, such as in the event of a water landing. An additional red light is illuminated when the hydraulic pump has electrical power supplied to it. In the event that the gear selector circuit breaker is tripped, no gear position lights would be illuminated.

A landing gear position advisory system was also installed in the airplane. The system was designed to provide an audible status of the gear position to the pilot. The system functioned by using the electrical signals sent to the landing gear position lights and monitoring the airplane's airspeed from the pitot static system.

Based on the airplane's airspeed and landing gear position as sensed by the system, the system was designed to arm itself when the threshold airspeed was exceeded. Once armed, the system normally provided a voice message advising the pilot of the gear position when the airplane slowed to the threshold airspeed, such as prior to landing.

When activated, the system was designed to provide an audible message "Gear is up for water landing" or "Gear is down for runway landing" based on sensed gear position. In addition, a lighted Gear Advisory push button switch flashed upon system activation. The pilot may cancel the advisory and audible advisory by pressing the switch.

In the event that the landing gear positions were not consistent when the system activated, such as the gear was in transit or all four gear were not all up or all down, the system was design to provide an audible "Check gear" annunciation to the pilot.

Electrical power was supplied to the system through three circuit breakers. One 25-amp breaker protected the circuit for the hydraulic pump. A second 5-amp breaker protected the circuit for the gear selector handle and the gear position lights. The third 2-amp breaker protected the circuit for the audible gear advisory system.

The installation manual for the gear position advisory system stated that the recommended airspeed threshold setting is the airplane manufacturer's required final approach speed plus 10 - 20 knots.

The Cessna 182Q Information Manual stated that the normal landing approach speeds were 70 -80 knots with the flaps up, and 60 -70 knots with the flaps down.

The wreckage was released at the conclusion of the on-scene investigation and follow-up testing on October 10, 2006, and was acknowledged by the Barron County Sheriff's Office.

The Federal Aviation Administration and Cessna Aircraft Company were parties to the investigation.

NTSB Probable Cause

The pilot's inadvertent attempt to land on water with the wheels down and his failure to verify the gear position prior to landing. Contributing factors were the inoperative gear system due to the open gear selector circuit breaker, which tripped for undetermined reasons.