Humans have been flying into mountains since the dawn of flight. It’s what some of us do. We know the mountains are there but perhaps it’s another version of “see and avoid.” It only works when the target is seen—not so well if it isn’t.
Then comes Risk Management—the watchword in aviation for decades. No matter how we rationalize it, there is some risk in leaving the planet. The management part comes in determining how much you’re willing to take on—especially when carrying passengers and should that make any difference?
A preliminary report from the NTSB’s August 2015 files serves as a case study on what might be a reasonable risk or what might be a bridge too far. You be the judge. All the usual caveats about preliminary reports apply. However the general circumstances, if not probable cause, seem to be well established.
According to the NTSB, a Cessna 172 collided with mountainous terrain (a vertical rock face) at an elevation of 5,046 feet. The VFR flight departed Helena, Montana, at about 2215 Mountain Daylight Time and crashed about 15 minutes later. The destination was White Sulfur Springs, which was about 20 minutes beyond the crash site if a direct course were flown.
A few items for your consideration:
- As noted on the chart, there are some 8- to 9,000-foot mountains on the 45 mile route with smaller ridges in between. The approximate accident location was 18 miles east of Helena, so apparently the crash occurred before getting to the higher mountains.
- The 59 year old private pilot had obtained his certificate less than a year before the accident but had logged an impressive 280 hours, almost all of which were in the accident aircraft. He had 3.8 hours of night flight, but only .8 in the prior eight months. No indication if he was current to carry passengers at night although really not relevant here since this would be hard to describe as a landing – the flight never got that far.
- The engine appeared to be producing power and the flaps were set at 10 degrees – an unusual configuration for cruise.
- The weather at Helena included winds from 250 degrees at 5 knots, visibility 5 statute miles, haze, an overcast cloud layer at 4,800 feet, temperature 22 degrees C, and dew point 4 degrees C. Density altitude was calculated to be about 7,200 feet.
- Aircraft instrumentation and portable device information was not reported in the preliminary investigation, so there is no data regarding synthetic vision or other terrain avoidance equipment.
- Dark night conditions prevailed.
- A family member was on board.
The late great comedian George Carlin in the weatherman sketch noted that tonight’s forecast is for dark—a profound observation.
If you’ve flown a dark night VFR flight, it’s best done mostly on instruments regardless of weather reports. There is a distinction between a dark night, which some would call redundancy, and a not-so-dark night. VFR with a full moon, especially with many ground lights near a large city, can be done with a reasonable degree of safety. Over water and in unpopulated terrain it’s an instrument game. A complete engine stoppage in any kind of dark would be problematic but we rationalize that those are rare.
Mountains compound things tremendously even if the pilot doesn’t suffer spatial disorientation. You can be cruising along minding your own business when the earth suddenly rises up to inflict a fatal sudden stop. Many old timers will not fly in the mountains at night regardless of how good the weather is and some avoid night flight completely.
In the flatlands it’s the dark departures and arrivals that cause problems assuming a reasonable enroute altitude. That can be managed by not flying into short fields unless good local knowledge keeps you out of the rough. Electronic navigation to supplement poor human night vision is invaluable while enroute and at the destination.
So based on what is known at this point, was this a prudent flight, in your view? Should a passenger be factored into the equation in determining risk?
Read, Safety Pilot: Landmark Accidents “Comfortable and complacent: A dark night, high terrain, and a climbing skyline” and take the Air Safety Institute’s “Mountain Flying” online course.