Make sure you have enough of it:

This is an interesting read for those who breath oxygen aloft.  

 
 
NTSB Identification: ERA09FA429
14 CFR Part 91: General Aviation
Accident occurred Thursday, July 30, 2009 in Ravenswood, WV
Aircraft: CIRRUS SR-22, registration: N581DS
Injuries: 1 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 July 30, 2009, at 2149 eastern daylight time, a Cirrus SR-22, N581DS, was destroyed when it impacted terrain in Ravenswood, West Virginia. The certificated airline transport pilot, the sole occupant, sustained fatal injuries. Instrument meteorological conditions prevailed, and an instrument flight rules flight plan was filed for the Title 14 Code of Federal Regulations Part 91, personal flight. The flight originated from York Municipal Airport (JYR), York, Nebraska, about 1840, and according to the flight plan, was bound for Eagle Creek Airpark (EYE), Indianapolis, Indiana.

According to the non-pilot owner of the airplane, he and the accident pilot completed the flight from EYE to JYR at 25,000 feet while breathing supplemental oxygen from the on-board oxygen system. The pilot then departed on the return flight to EYE. The oxygen system was not serviced prior to departure, but was going to be serviced at EYE "on Monday."

According to preliminary information from the Federal Aviation Administration (FAA), and data downloaded from the Recoverable Data Module (RDM), the flight was incrementally cleared by air traffic control (ATC) to climb to 25,000 feet. At 1857, the flight was cleared to climb from 22,000 feet and to maintain 23,000 feet. The pilot acknowledged the instruction, but the controller noted that his voice had changed, and had taken on a "helium/Mickey Mouse" quality.

At 1905, the pilot announced that he was climbing to 26,000 feet. ATC had cleared the pilot to 25,000 feet and noted that the pilot was "stepping all over himself." Later, the pilot was given a vector to avoid traffic, which the pilot acknowledged, but when instructed to proceed on course, the pilot's response was "unreadable." At 1925, the pilot requested a descent to 12,000 feet, and "sounds in distress and out of breath."

The flight was first cleared to descend to 24,000 feet, which the pilot acknowledged, and then at 1927, the pilot was instructed to descend to 12,000 feet and was issued the altimeter setting. The pilot acknowledged the call and repeated the altimeter setting. However, the airplane maintained cruise flight at 25,000 feet.

ATC attempted to contact the pilot for approximately 6 minutes before the pilot responded with, "Go ahead." The airplane was again issued a clearance down to 12,000 feet and instructed to "begin your descent." An airline pilot on the frequency commented that the accident pilot sounded "incoherent." The last radio transmission received from the airplane, at 1937, was the "pilot's labored breathing." At 2051, the airplane crossed directly over EYE, at 25,000 feet, and maintained its on-course heading.

The airplane continued in cruise flight at 25,000 feet until 2146, when engine power and fuel flow parameters dropped to zero, and engine cylinder head and exhaust gas temperatures dropped significantly. A brief simulation of flight instruments for the final minutes of the flight showed the airplane increasing nose-up pitch and decelerating at 25,000 feet until a sharp, descending left spiral was entered. The instruments then depicted a random string of spiraling left and right turns and 360-degree rotations around the roll axis before the data stream was lost.

The Ohio Air National Guard launched F-16 Fighting Falcon jets in pursuit of the accident airplane, but the Air Force pilots were unable to gain the pilots attention visually or by radio. They noted that the pilot appeared "unconscious" at the flight controls. The Air Force jets remained with the airplane until it departed controlled flight, and descended into terrain.

A review of FAA records revealed that the pilot held an airline transport pilot certificate with ratings for single engine and multiengine land airplanes; flight instructor certificates for airplane single engine, multiengine, and instrument airplane; and a commercial pilot certificate for rotorcraft and single engine seaplanes. Additionally, he held a Learjet type rating. The pilot reported 18,500 hours of total flight experience on his most recent application for a Federal Aviation Administration first-class medical certificate, which was issued on July 14, 2009.

The pilot's logbook was not immediately recovered, but a review of an insurance renewal form dated July 23, 2009 revealed that the pilot reported 18,700 total hours of flight experience, 500 hours of which were in make and model.

According to FAA records and a conversation with the owner, the airplane was manufactured in 2008, and had accrued approximately 500 total aircraft hours. The most recent annual inspection was completed on July 22, 2009, at 433.5 total aircraft hours.

At 2153, the weather reported at Mid-Ohio Valley Regional Airport (PKB), Parkersburg, West Virginia, located approximately 30 miles northeast of the accident site, included winds from 170 degrees at 3 knots, and 2 ∏ statute miles visibility in mist. There were scattered clouds at 1,600 feet and 2,600 feet, and a broken ceiling at 3,800 feet. The temperature was 22 degrees Celsius (C), the dew point was 21 degrees C, and the altimeter setting was 29.93 inches of mercury.

The airplane was examined at the site in mountainous terrain on July 31, 2009. There was an odor of fuel, and all major components were accounted for at the scene. The wreckage path was oriented approximately 115 degrees magnetic, was about 550 feet long, and widened along its length to a width of approximately 150 feet. The first 200 feet of the wreckage path was on the down slope of an open pasture, at the top of a wooded ridgeline. The remainder of the wreckage path was distributed down a steep, heavily wooded incline to a creek bed.

A large area of grass just beyond the initial ground scar, and trees along the wood line, exhibited browning of the foliage consistent with exposure to fuel. The airplane was significantly fragmented and scattered over the entire area. Fragments associated with the engine, propeller blades, and the flight control system were accounted for along the entire length of the wreckage path. The primary flight and multi-function displays were destroyed and impossible to identify. The Cirrus Airframe Parachute System (CAPS) was deployed due to impact forces.

The Recoverable Data Module (RDM) and components from the airplane's supplemental oxygen system were retained for examination at the National Transportation Safety Board (NTSB) materials and flight recorders laboratories.