A few weeks ago I wrote about the Mid-Air Collision of Glider and Jet near Reno: ASG-29 vs. Hawker XP800 and speculated about the glider's transponder.

We won't really know everything that we can until the NTSB finishes their investigation. Based on the information I've read and heard this week, there's a good chance that the accident was preventable.
I'm led to believe that the ASG-29 had a working transponder on board but that it wasn't currently powered up. If that's the case, it means the glider was virtually invisible to the jet's pilot and co-pilot, not to mention Reno Air Traffic Control. Even if the jet pilots couldn't have visually detected the glider (which is pretty difficult going that fast), their TCAS would have picked up the transponder signal and suggested a safe diversion.
There's a lot more I could say about this, but I'll hold off until the NTSB publishes their report a few months from now.

Since then I've had the chance to hear from people who met with the NTSB investigators and learn a lot more about the incident. But I waited to say anything more until the NTSB released their preliminary findings, which they recently did.

Here's the relevant section from those findings:

The glider was equipped with a panel mounted communication radio, global positioning system (GPS) unit, and a transponder; however, the pilot did not turn on the GPS and transponder. The transponder's activation is not required for glider operations (for more details see 14 CFR Part 91.215). According to the glider pilot, he did not turn on the transponder because he was only intending on remaining in the local glider area, and because he wanted to reserve his batteries for radio use. The glider was equipped with two batteries (one main and one spare), however, due to the previous glider flights, the pilot was unsure of the remaining charge in the battery.

So there we have it.

It should come as no surprise that pilots in the Reno area have a renewed interest in battery life and keeping their transponders on as long as possible. Many are also looking at TPAS devices such as the Monoroy ATD-300 Traffic Watch

Posted by jzawodn at September 25, 2006 07:30 AM

Reader Comments
# hack said:

You never got around to telling us about the DG300 crash at Truckee.

Is this because the pilot decided not to report it?

on September 25, 2006 09:59 AM
# Zurchman said:

There are only two ways that this accident could have been worse for the Soaring community: 1) it could have involved an airliner, and 2) it could very well have resulted in injuries or deaths.

It's interesting that a recent issue of "Soaring" had just discussed the transponder issue and pointed out that glider echoes from primary radars may be either faint, intermittent, or nonexistent, so without a transponder a glider may very well be "invisible" to ATC.

It is unreasonable to risk $10 millon for the Hawker, plus about $100,000 for the glider but not spend $30 for a transponder battery.

It may be legal, but anyone who flies a glider at 16,000 MSL without an operating transponder is nuts.

on September 26, 2006 10:14 AM
# rr said:

So how low before it's not nuts to have no operating transponder? I'd say 0 AGL.

I have a TrafficScope VRX, and let me just say it really reduces the enjoyment of flying. Instead of being blissfully unaware of how much traffic your scan is missing, it is a constant reminder that it isn't really a Big Sky Theory but more of a Medium to Smallish Sky Theory.

on September 27, 2006 07:42 AM
# Doug Conley said:

Questions from a non-pilot tourist to your blog:

1) Did we ever find out if the jet had a powered-up transponder? If so, how did this happen?
2) I understand that the glider pilot survived. I'm curious how much notice he had before bailing out. Although I'm not a pilot, I do understand that sound travels at approx. 600 mph and the jet was traveling at approx. 345 mph. Since most of the sound would be broadcast in the direction of thrust, I can't imagine that the glider would have heard much of anything. I surmise that in a glider, you have a rather large range of vision?

Thanks for the article. Very interesting.

As a somewhat unrelated question -- In law or fact, who would be liable for the damage to the respective planes? No-fault?

on May 31, 2009 03:47 PM
# Jeremy Zawodny said:


(1) the Jet had TCAS and a transponder, I believe. The glider, however, had a transponder that was not powered on. Had it been, this would not have happened.

(2) I suspect the glider had a few seconds of warning at most. If he'd seen it coming, I'm sure he first tried to out-maneuver it before even considering a bailout.

As for who is/was at fault. I think it's a no-fault situation, since neither pilot had broken any of the rules (common sense, aside) and it's the responsibility of all pilots to "see and avoid" as the FAA likes to say.

on May 31, 2009 05:25 PM
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