Homebrewed Loss of Control

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A few months ago, the NTSB released its report on the Jan. 14, 2016, crash of a Beech C35 in which the pilot, who was the only person on board, was killed. According to the Safety Board, the accident was the result of the non-instrument-rated pilot's decision to fly the airplane in instrument meteorological conditions at high altitude for greater than 30 minutes without the use of supplemental oxygen, which resulted in hypoxia and a subsequent loss of control. Contributing to the accident was the pilot's use of multiple impairing medications. And the more you find out about the accident, the worse it gets.

The pilot, age 62, had been taught to fly by his father and supposedly had a passion for flying. The Beech V-tail Bonanza was registered to him on Sept. 15, 2005, at his address in Tabernash, Colorado. He held a private pilot certificate with a rating for single-engine land airplanes but did not have an instrument rating. When he got his most recent FAA third-class medical certificate, on Nov. 6, 2015, he reported having flown 600 hours total with 20 hours in the six months before his visit to the medical examiner. His medical certificate required him to have glasses available for near vision.

The airplane was powered by a Continental E185 series engine rated at 205 horsepower. Typical cruise was 154 knots at gross weight of 2,700 pounds. The service ceiling of the airplane was reported by the NTSB to be 18,500 feet MSL, which is interesting because, as you will see, during the accident flight, the pilot accepted an ATC clearance to maintain Flight Level 190, which may or may not have been above the service ceiling, depending on things like the actual barometric pressure. But, as you'll also see, the pilot may have been in no condition to do the math to figure that out.

Investigators learned that the pilot had checked on weather with Lockheed Flight Service, although they were unable to retrieve the information the pilot had been given. But the NTSB weather study for the accident flight made it obvious that the flight from Provo Municipal Airport (KPVU), Provo, Utah, to Granby-Grand County Airport (KGNB), Granby, Colorado, would encounter instrument conditions. No flight plan was filed for the flight.

It was about 4:20 p.m. when the pilot took off from KPVU, elevation 4,497 feet MSL. The airplane circled in the vicinity of the airport as it climbed to 12,000 feet MSL and then headed east toward mountainous terrain. According to recorded radar data, the flight continued climbing and reached 14,500 feet MSL at about 4:41. For the next 12 minutes, it continued in cruise but did not hold a precise altitude, instead fluctuating between 14,500 and 14,000 feet. Then, it dropped down to about 13,000 feet and started climbing again.

It wasn't until 5:04:40 that the pilot put out a radio call to Air Traffic Control. "Denver Center, this is Bonanza two zero two five delta," he radioed. The controller immediately responded, "Bonanza two zero two five delta, go ahead." There was no reply and the controller radioed, "Bonanza calling Denver Center, say again." At 5:04:52, the pilot said, "Yes, it's two zero two five delta, I'm flyin' from, um, Salt Lake to Granby."  The controller asked the pilot for his position, and at 5:05:09 the pilot responded that he was "eight point nine miles from seventy four victor," followed at 5:05:18 by, "three hundred radial." The identifier 74V is for the Roosevelt Municipal Airport at Roosevelt, Utah. The airport does not have a co-located VOR station. The nearest one is the Myton VOR, 8.5 nautical miles to the south-southwest. Nevertheless, the controller had no trouble finding the Bonanza on radar. "November two zero two five delta, there ya are and, uh, the, uh, Grand Junction altimeter two niner niner eight."

The transcript of radio calls provided by the FAA does not show that the pilot specifically asked for flight following services or requested any kind of clearance. Recorded radar data indicated that for the next 21 minutes, the airplane continued on its course but eventually began climbing and had climbed above FL 180 by 5:36:43, when the controller radioed the pilot with a request for him to "say altitude."

The pilot responded by transmitting, "altitude eighteen thousand," which prompted the controller to radio at 5:36:50, "...you have to have an IFR clearance to go up to flight level one eight zero, uh, would you like an IFR clearance?" The pilot responded, "That would be great. I just want to get over this [unintelligible] get back down." It's speculation, but it would make sense if the pilot wanted to get over some clouds, since the tallest mountains on a direct line between the Roosevelt Municipal Airport and the pilot's destination at Granby as shown on a sectional chart only go up to just over 12,000 feet MSL.

The controller asked, "Are you IFR equipped and, uh, capable?" The pilot said, "I am IFR equipped," but said nothing of his capabilities. The controller did not pursue the point and radioed at 5:37:15, "Tell ya what and, uh, maintain block altitude, uh, one seven thousand to flight level one niner zero." The pilot then responded, "one niner zero," and the controller issued him a  direct clearance to the Granby airport. Rather than reading back the clearance, the pilot responded with, "That's correct." The airplane then stopped its climb at 18,400 feet, according to radar data, and, a minute later, the controller asked, "If I, uh, assign you flight level one niner zero, are you able to, um, maintain that? Or, do you want somethin' lower?"

The pilot's response could very well indicate that he was being affected by hypoxia, because his reply had no relationship to the controller's question. "Right now, I'm in the clouds," was what he said, prompting the controller to ask again, "Are you able to maintain flight level one niner zero?" The pilot's reply: "Uh, we're getting' there."

But the airplane was not "gettin' there." It had climbed to just short of 18,700 feet and abruptly descended to 17,400 feet. At 5:41:02, the controller radioed that he showed, "You're goin' down, would you like, uh, lower?" The response was unintelligible. The airplane then climbed up to about 18,500 feet. The controller radioed the pilot, but there was no response. He tried again about 10 seconds later and said, "I show you goin' north now. Are you okay?" The pilot replied, "A little bit."  The airplane then turned to the west and started descending in a right spiral.

At 5:41:36, the controller radioed, "I see you in a turn and descending. Are you under control there?" The pilot answered, "Uh, yes." The controller advised, "You can go down to one one thousand, descend and maintain one one thousand, that's the lowest I can get you." The pilot could be heard saying, "Alright, [unintelligible] clear there." The controller may have believed he was asking about the weather, because the controller radioed that he didn't have any weather reports for the area the pilot was in and asked if he was planning to head back to the west. The pilot's response again did not address the question. "I'm at seventeen [thousand feet] now," is what the pilot radioed at 5:42:04.

At 5:42:08, the controller told the pilot, "I need to know, are you planning, uh, you're kind of doin' some s-turns there, are you proceeding to Granby, or are you gonna go, headin' back west?" The pilot did not respond and, at 5:43:30, the controller asked, "November two zero five delta, how do you hear Denver?" When there was no response, the controller repeated the transmission. At 5:42:51, the pilot radioed, "I hear you fine." He also said something else, but it was unintelligible.

It apparently had become clear to the controller that the pilot was in trouble, and he offered that "the Meeker Airport's currently at your three o'clock and about one seven miles." When the pilot did not respond, the controller said, "November two zero two five delta, you need to talk to me." The reply was unintelligible, and the controller told the pilot that he was down to 14,600 feet and should not go below 11,000 feet. There were no further transmissions from the pilot, and the controller kept trying to raise the pilot and radioed in the blind the position of the Meeker Airport. The controller asked the pilots of other aircraft to try to raise the Bonanza and to listen for an emergency locator transmitter signal, but the effort was futile.

The Safety Board said the time of the accident was 5:45 p.m. Search crews did not locate the site until just after 10:30 the following morning. The airplane had crashed in mountainous terrain about 19.5 miles west of Meeker, Colorado. The elevation of the terrain was between 6,200 and 6,400 feet MSL. Pieces of the airplane were spread over a wide area, indicating an in-flight breakup. For example, the right stabilizer was found 890 feet from the main wreckage; the left stabilizer was 1,430 feet away in a different direction. 

Investigators found no evidence of an engine problem or failure of any of the airplane's systems before the accident. The weather observation at the Meeker Airport about 10 minutes after the crash included calm wind, an overcast ceiling at 4,300 feet AGL, temperature minus 2 degrees C., dew point minus 7 degrees C. and an altimeter setting of 29.89. A review of the weather by an NTSB meteorologist found that conditions en route were conducive to cloud formation between 9,000 and 15,000 feet. Icing was indicated between 9,000 feet and 14,000 feet. Weather radar and satellite images showed it was likely that some cloud tops went up to 19,000 feet. 

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Investigators found that a homemade oxygen system had been installed in the airplane. In fact, they studied a photograph of the airplane taken before the accident flight, which showed the baggage door open and two aluminum oxygen bottles fastened to the fuselage in the rear baggage area. They appeared to be of a type used in medical facilities. Each could hold 24 cubic feet of oxygen at a pressure of 2,015 pounds per square inch (psi). Each tank had a valve to which vinyl tubing was attached, feeding a vinyl oxygen mask. The valves on the bottles would not have been accessible to the pilot during flight, so the pilot would have had to set the oxygen flow before takeoff. The valves as found in the wreckage were both in the off position. Both bottles still held oxygen after the accident, one at 600 psi and the other at 1,200 psi.

The toxicology report prepared by the FAA's Bioaeronautical Sciences Research Laboratory in Oklahoma City showed that the pilot had been using medications which are classified as potentially impairing. These included diazepam, hydrocodone, cyclobenzaprine and zolpidem. Diazepam is used to treat anxiety, alcohol withdrawal and muscle spasms. Hydrocodone is an opioid pain medication. Cyclobenzaprine also is used to block pain. Zolpidem is used to treat sleeping problems.  

The Safety Board suggested that the medications had combined effects that contributed to what it termed the pilot's "unsafe decision making" and led him to initiate the flight in the first place into nighttime conditions over mountainous terrain. The board also suggested that the pilot's "inconsistent communications and erratic flight track was characteristic of a state of hypoxia, and hypoxia likely resulted in the pilot's inability to maintain control of the airplane."

Perhaps the pilot felt he was stacking the deck in his favor with a homemade oxygen system. But isn't it doing the opposite if you're not able to control the valves on the tanks in the back while you're busy flying? Perhaps the pilot believed he was stacking the deck is his favor when he accepted the IFR clearance. But don't the facts show that pilots who are not qualified for IFR, yet try it, frequently wind up as statistics? Perhaps the pilot thought he was stacking the deck in his favor by using plenty of medications to contain the symptoms of whatever medical conditions afflicted him. But isn't there a reason for warnings being placed on medication labels and for the FAA frowning on the use of potentially impairing drugs when a flight is in your immediate future? And there certainly are more questions for us to ask about how this happened and how we can avoid situations like this and continue dealing ourselves only winning hands.

Peter Katz is editor and publisher of NTSB Reporter, an independent monthly update on aircraft accident investigations and other news concerning the National Transportation Safety Board. To subscribe, visit www.ntsbreporter.us or write to: NTSB Reporter, Subscription Dept., P.O. Box 831, White Plains, NY 10602-0831.