Friday, January 19, 2007

Accident of the Week

This week's Accident of the Week is truly a tragedy. Four members of a family board for a short flight across North Carolina. The pilot and father is instrument rated. They are setting up for the approach to their destination when something goes horribly wrong:
NTSB Identification: NYC07FA052
14 CFR Part 91: General Aviation
Accident occurred Sunday, December 31, 2006 in Charlotte, NC
Aircraft: Cessna TR182, registration: N7090S
Injuries: 4 Fatal.

This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed.

On December 31, 2006, at 1124 eastern standard time, a Cessna TR182, N7090S, was destroyed when it impacted terrain in Charlotte, North Carolina. The certificated private pilot and the three passengers were fatally injured. Instrument meteorological conditions prevailed and an instrument flight rules (IFR) flight plan was filed. The flight originated at the Dare County Regional Airport (MQI), Manteo, North Carolina, and was destined for the Shelby Municipal Airport (EHO), Shelby, North Carolina. The personal flight was conducted under 14 CFR Part 91.

According to preliminary air traffic control information provided by a Federal Aviation Administration (FAA) inspector, the pilot checked in with Charlotte Approach Control at 1057, at an altitude of 6,000 feet. The controller asked the pilot what type of approach he wanted at Shelby, and if he had the current weather. The pilot responded, "ah we do the gps rnav rnav five," and stated he did not have the current weather. The pilot was then instructed to descend to 5,000 feet and to inform the controller when he had the weather. The pilot acknowledged the transmission, and shortly after was instructed to fly a heading of 260 degrees. The controller asked the pilot whether he wanted vectors for the approach, and the pilot responded, "we're probably get take a little help right now."

At 1109, the pilot stated, "ah my heading is way off I'm banking back I am now tracking three oh five trying to get back." The controller instructed the pilot to "turn left, heading two five zero." The pilot acknowledged the instruction; however, he did not maneuver the airplane to the assigned heading. The controller subsequently issued additional vectors to assist the pilot and instructed him to "check [his] altitude," when he observed the airplane 400 feet too low. After observing the airplane continuing to the north, at 1116, the controller asked if the pilot was "doing alright," and the pilot responded, "I'm struggling a little." Over the next 60 seconds, the airplane continued it's right turn, heading to the south, and the controller issued several vectors to the pilot to assist him in turning left, to a westbound heading. At 1118, the controller informed the pilot that he appeared to be correcting, and the airplane appeared to be at the correct altitude. One minute later, the controller informed the pilot that he was again drifting to the southwest, and was issued a heading of 280 degrees. The pilot acknowledged the transmission, and at 1122, the controller issued another vector of 270 degrees. The pilot again acknowledged the transmission, and no further transmissions were received from the pilot.

A witness, who first heard the airplane as he was standing on his back porch, stated that the airplane sounded as if it was "going up and down, searching for altitude." The airplane then appeared through the cloud deck, in a "nose-dive," at an approximate 80-degree nose-down attitude. The witness observed the right wing separate from the airplane as it continued to travel downward at a high rate of speed. The airplane then disappeared behind trees, and shortly afterwards the witness heard the sound of the impact.

A second witness also heard the airplane before he observed it. He stated that he heard the airplane's engine "sound loud one second and then cut out the next." This pattern repeated several times, and then the witness heard a loud "bang," and observed parts of the airplane "falling from the air." The airplane continued until it impacted the ground in the backyard of a residence.

The airplane impacted a residential area, and the debris field extended into several backyards over a 1-block area. The initial point where wreckage was observed was along a road where the left wingtip and left wing came to rest. In a front yard adjacent to the road, the left aileron and a portion of the left elevator were also observed. The wreckage path continued over several yards, oriented on a heading of 280 degrees. Located along the wreckage path was the right aileron, pilot-side door, and a portion of the roof and elevator.

Approximately 250 feet from where the left wing was observed, the airplane impacted power lines in the backyard of a residence. The wreckage path continued 35 feet from the power lines, to a 12-foot long and 2-foot deep crater. Approximately 12 feet from the crater, the main wreckage impacted the base of a tree. The main wreckage included the cockpit area, fuselage area, right wing, a portion of the empennage, and one propeller blade. On the other side of the tree, in another backyard, additional fragmented fuselage and cabin sections were noted, as well as a second propeller blade.

The engine was located, embedded in the side of a residence, approximately 60 feet from the main wreckage.

The airplane and engine were recovered from the site, and transported to a facility for further examination. The airplane was reconstructed, and all components were accounted for. Examination of the left wing revealed it remained intact, and separated at the wing root. Both the left and right wing struts also separated from their attachment points on the wing and fuselage. Aileron control continuity was confirmed from the cockpit area to the broomstraw-separated cable ends in the wing root. Rudder and elevator control continuity was confirmed from the cockpit to the flight control surfaces.

Examination of the flap actuator revealed the flaps were in the retracted position.

The left wing attachment hardware and left strut attachments were retained for further examination.

The engine could not initially be rotated due to impact damage to the number 2 cylinder. The cylinder was removed, and the engine was successfully rotated by hand at the propeller flange. Thumb compression and suction were obtained on all cylinders, and valve train and crankshaft continuity were confirmed to the rear accessory drive section. Examination of the top and bottom spark plugs, revealed their electrodes were intact and light gray in color. The dual magneto was impact damaged, and could not be tested for spark.

The vacuum pump was disassembled, and impact damage was noted to the vanes; however, the drive coupling remained intact.

Examination of the propeller assembly revealed all of the propeller blades were separated from the propeller hub. Two of the blades displayed torsional twisting and chordwise scratching, and the third propeller blade was not located.

The pilot held a private pilot certificate with ratings for airplane single engine land and instrument airplane. His most recent FAA third class medical certificate was issued on April 14, 2006. At that time, the pilot reported 425 total hours of flight experience.

Weather reported at CLT, at 1100, included winds from 040 degrees at 4 knots, 3/4 mile visibility with rain and mist, a broken cloud layer at 500 feet, an overcast cloud layer at 1,200 feet, temperature 52 degrees Fahrenheit, dew point 50 degrees Fahrenheit, and an altimeter setting of 30.31 inches mercury.

While we'll ultimately see what the NTSB has to say, you have to guess out of the box that this was spatial disorientation leading to an in-flight breakup due to loss of control. If the NTSB does reach that as a probable cause determination -- and that's a big if -- let's hope that it is also able to shed some light on why, after several hours of routine flight in IMC ( shows that the accident flight departed MQI around 9:10 a.m., accident time was 11:24 a.m.), this pilot becomes so disoriented as to lose control of the airplane.

Perhaps there was an instrument failure. Perhaps the autopilot (if there was one, the report doesn't say) became inoperative at the worst possible time. Perhaps something -- anything -- other than pure pilot error.

Looking at the chronology of events, you see that the pilot first reported indications of difficulty at 11:09 a.m. The accident took place about 15 minutes later. The cloud tops are not indicated, but if possible, one escape strategy might have been to cancel the approach and request a clearance to someplace on top of the clouds.

Maybe that wasn't possible under the prevailing conditions. Maybe that wouldn't have helped. But it's worth thinking about if you are ever caught in that situation. Troubleshooting a problem in IMC is hard, especially if you are single-pilot and lacking an autopilot. So, if you can, consider climbing to VFR conditions and troubleshooting there. Then you can decide: Fly the approach or, if possible, divert to a destination where VFR conditions prevail.

Godspeed to the family (a third child was not on board) and friends.

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