Fatigue + Darkness + VFR Only =


Act I

Pair a Mooney M20 airframe with a 200 hp engine and you have a great cross country machine. Our pilot plans to take advantage it by launching on a 1300 nm adventure at 0830.  The weather is clear all day and all the way so lack of an instrument ticket is not a problem.

Act II

We next see our Mooney owner 900 nm later in Tonopah, NV, preparing to launch on his last leg at 2000. Hold on a minute. Even if he is only making 150 knots over ground (1100 / 150 = 7.3) and stopped once before (1 hour for fuel and a meal), it should not have taken 11 and a half hours

 to get to this point. What has he been doing? AOPA M20 Fact Sheet

Just a quick 200 nm over the mountains to the outskirts of San Francisco (SkyVector.com).  A witness later reports he appeared tired. No kidding. He’s been at this at least 12 hours (including preflight and checking weather).

Sunset is beautiful as a Sol disappears on the other side of Yosemite. Even in the Mooney, he can’t catch the sun. The rest of the trip will be in the dark.

Act III

At 2100, there is a loud crashing sound. Of course, this brings up the question about a tree falling in the forest with no one there to hear the sound. An Emergency Locator Transmitter signal is received at 0024. The wreckage is later found at 11,000 feet, which is about 1000 feet below the terrain in that particular spot and 2500 feet below the Minimum Obstacle Clearance Altitude for the area. Crash site map can be seen planecrashmap.com.

Yes, this one is more than a little light on my usual storytelling. The Brief of Accident doesn’t give me a great deal to work with. This same lack of detail leaves me a with a lot of questions, so I’ll concentrate there.

The sole Causal Factor in the report is “failure of the pilot to maintain adequate altitude to clear mountainous terrain.” Listed as a contributing factor was “pilot fatigue due to a lengthy cross-country flight.” I don’t disagree fatigue was contributing, but there was no mention of three other matters.

1. Our long-range Mooney pilot was flying through mountainous terrain at night without an instrument ticket. According to the report, there was no ground or moon illumination at the time of the accident. What the report does not say is whether the wreckage indicated Controlled Flight Into Terrain (CFIT) or a Spatial Disoreintation (SD) induced death spiral. Perhaps his original plan was to be on the ground at his destination before sunset, but he was way behind such a time line before departing Tonopah.

2. Lacking a pressurized cockpit, he should have been flying on oxygen. You can argue about the 30 minutes you are allowed between 12,500 feet and 14,000 feet, but this fellow did not show himself to be a master of the clock. “Minimum Flight Elevation of 13,500 feet” and “did not have any ground or moon illumination” is all I need to hear.
3. Why was it so important for him to get there that night?

I have a lot of respect for NTSB investigators and the work they do, but I think they failed to go far enough on this one.  In their defense, I will say accident investigation has changed a lot since this polot died on April 1, 1991. Hindsight is 20/20, yes?

What would you have done at Tonopah? Called it a night and finished the next day or pressed on?

The Brief of Accident and Factual Report for this accident can be found by searching for Aircraft Registration Number N1941Y or Accident Number LAX91LA154 in the NTSB Aviation Accident Database.

Image from monocounty.org.

What say you?