Today’s post is more of a public service announcement than anything. It isn’t flight instruction, especially since I’m not yet qualified, but I want every pilot to learn from it.
While perusing YouTube recently, I saw the video above in the side bar. I was a bit put off by the title, but I watched anyway. While the video is low quality, which is understandable since it is from the mid-80s and spent 3 years laying in the Rockies, it is bearable to watch until the end. As you will see from the beginning of the video, the aircraft departed Granby, Colorado and crashed en route to Denver. So, that should set the stage for a mountain flying discussion.
Before I delve into more details regarding the crash, lets talk about the aircraft and pilot. The aircraft was a Cessna L-19E Bird Dog, registration N4584A. According to the NTSB reports, the plane had a Continental O-470-11 rated for 213 HP. Now, that’s plenty for operating at the 10,000+ feet altitudes in that area, but you have to be on your toes and know how to handle yourself in the mountains. Unfortunately, since the paperwork shows addresses in Texas, it seems the pilot was probably not local and may or may not know much about mountain flying. Since the flight plan information indicates a 1PM departure on a 77 degree day, I’m leaning toward him not knowing much as that put the density altitude at almost 14,000 feet along his route of flight. That’s only about 6000 feet below the service ceiling for the Bird Dog, meaning he was skirting the edge of the aircraft’s abilities.
Now, I did some perusing on Google Earth and I think I found the little lake that they fly over just before the crash. It’s on a bit of an oblique angle looking toward the route of flight, because I want to highlight that the terrain was rising pretty steeply and it starts rising even faster as they approach the mountain.
So, continuing my investigation, I followed the approximate flight path in Google Earth to an area that I believe is the site of the crash. It is shown here on more of an oblique to highlight just how much the terrain was rising.
The little yellow pin is where I think the crash happened and even though he had plenty of plane to be flying in the Rockies, even my limited knowledge of mountain flying suggests he shouldn’t have been there. The problem is he’s flown up the little valley way past his point of no return at the altitude he was flying. He ran out of altitude and started turning way too late. To make matters worse turning the other way wasn’t any better. In the end the terrain sneaked up and he got low, slow, and over-banked. The sad end to this tale is that he stalled and impacted the terrain.
So, what should he have done? He should have turned back over the lake and started flying racetracks and climbing to a much safer altitude to cross that ridge. At the very least he should have turned back away from climbing terrain much sooner. If you want to take it even further, he should have left much earlier or much later when the temperature was lower and he probably should have taken a different route. The other thing to remember is that stall speed increases at higher bank angles. He cranked it into a pretty steep turn trying to get out of a rapidly worsening altitude deficient condition. The problem is, he didn’t need to crank so much, because turn radius decreases as speed decreases, so he probably could have safely turned back by dropping in some flaps, slowing down a little, and turning with a much shallower bank angle. Think slow flight à la the Private Pilot Practical Test Standards.
As for a better route, it looks like a river valley snakes through the terrain that is quite a bit lower than his apparently direct route. While it is a somewhat longer route, it allows more terrain clearance and gives more time for the climb over the ridge. Most of the time the terrain elevation is below 9500 feet along that route and even at the highest point it is below 11,500 feet, which is a good 500 feet lower than the pass for which they were likely heading.
So, remember airspeed is life, altitude is insurance. Fly safely and have fun.