By David Jack Kenny
Risk tolerance is highly individual. AOPA Pilot contributor Barry Schiff, for example, surprised some readers by reporting that he’s no longer willing to make cross-country flights in single-engine airplanes at night. After logging tens of thousands of hours in hundreds of different aircraft models, Schiff found himself uncomfortable with the limited options available in the event of an engine failure—an emergency he’s actually faced three times.
Others draw their own lines elsewhere. A pilot who doesn’t mind traversing farmland in the dark might balk at crossing the mountains at night. Or perhaps IFR flight over mountains seems like a little too much to one who’s equally at ease crossing them in VMC and making instrument flights over flatter ground. With sufficient proficiency and appropriate equipment, extended cross-country flights over mountainous terrain in instrument conditions can be made with an acceptable margin of safety. The pilot who does that in a piston single, however, assumes a heavy burden of contingency planning. The potential for a single-point failure makes weather evaluation and choice of route especially critical in minimizing the risk that something will go wrong… and having someplace to go if it does.
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Shortly after noon on Dec. 1, 2013, a turbocharged Beech Bonanza took off from Baker City, Oregon, with five people on board. Climbing through 6,200 feet, the pilot contacted the Salt Lake City Air Route Traffic Control Center for his IFR clearance to Butte, Montana, some 234 nautical miles east-northeast. Their route traversed some of the most rugged mountain ranges in the continental United States.
The 1,050-hour private pilot had filed his flight plan online just before departure. He did not download a weather briefing at that time, and there’s no record of what weather information, if any, he’d actually reviewed before the flight. The question is of some interest, because while he’d departed Baker City VFR under a 6,000-foot ceiling, conditions would become considerably more challenging ahead. Airmets for IFR conditions, turbulence, and moderate icing below 20,000 feet extended across the route, with freezing levels between 7,000 feet msl and 8,500 feet msl and cloud tops forecast to exceed 18,000 feet msl. The Bonanza had no icing protection beyond pitot heat and the engine’s alternate air intake. Salt Lake Center cleared it to join V-121 at the Donnelly VOR at its filed altitude of 13,000 feet msl.
Twenty-six minutes later, the controller asked the pilot to confirm that he was established on the airway at 13,000 feet msl. His reply was “Negative … picking up too much ice. We’d like to divert to Salmon,” still some 70 nautical miles ahead. He also requested a descent to 11,000 feet msl, but the minimum IFR altitude in that sector only allowed the controller to clear him to 12,000 feet msl.
This exchange suggests that the pilot hadn’t yet grasped the gravity of his situation. Significant ice accumulation in an unprotected airplane over mountains is a full-blown emergency requiring an immediate and decisive response. A prompt return to the most recent place that was ice-free is the most obvious course, if not inevitably the best. Continuing into the same weather with the airplane already unable to maintain altitude isn’t a viable plan.
The controller approved the diversion and provided a vector back to the airway, but the Bonanza continued to descend. In response to a low-altitude alert the pilot attempted to climb back up from 11,500 feet msl, only to report “engine problems” 12 seconds later. Fifteen seconds after that, he radioed “… needs to go to three uniform two immediately.”
Johnson Creek Airport (3U2) is an unpaved strip in a narrow valley in Idaho. It is unattended, with no fuel or other services, and not maintained in the winter. It did, however, have the advantage of being almost directly below the Bonanza’s location as it descended through 10,000 feet. Five and a half minutes after first reporting ice, the Bonanza pilot radioed that he’d “lost his engine” and requested a heading for Johnson Creek Airport. That was the last transmission received from him; attempts to relay messages via passing airliners were unsuccessful.
An alert notice was issued at 1:28 p.m. Search-and-rescue efforts began at once, but the wreckage wasn’t located until January 10, nearly six weeks after the accident. The airplane had hit trees on a mountainside just over a mile and a half from the strip. The NTSB concluded that the engine had been choked by induction ice despite the spring-loaded alternate air intake designed to open automatically, while accumulated airframe ice degraded its glide performance.
There was no evidence that anyone on board survived the initial impact, but even if the pilot had managed a perfect dead-stick landing and they’d reached the ground uninjured they’d have been in serious trouble. Miles from the nearest town, the combination of harsh winter weather and difficult terrain would have placed them at grave risk of succumbing to hypothermia. Dehydration and hunger posed longer-term threats. The Bonanza’s owner left himself with no better option than trying to exchange an immediate emergency for a more protracted crisis.