Followup on 2019 Otter/Beaver midair

Wow. That photo is the most sad and sobering thing I've seen all day.
I wonder what the conversation in the back seat was like in those last few moments?

The video with the full animation is really interesting. Among other things, it shows a simulation of the Otter pilot's view, in which the Beaver lies just perfectly hidden by the window strut obstruction as the two planes get closer.
 
"Was not transmitting pressure altitude information", ... forgot to switch the transponder to ALT mode?
 
Ugh that still pic is sobering. Sucks. Hard to imagine these guys aren’t talking like on a CTAF or something.
 
Wow, just wow

So otter had left his transpinder off?
 
They didn't explain why the otter wasn't showing altitude. I'm curious why?
 
Huckster79 said:
Wow, just wow

So otter had left his transpinder off?
Click to expand...

The report did not state that the transponder was off, just that the GSL 71 was off. A GSL 71 is a control panel that interfaces to a GDL90. A GDL90 is an early UAT only version of ADS-B Out/In that was used in Alaska for the Capstone project that did testing on the ADS-B concept. The GDL90 is not compliant with the current ADS-B Out mandate, but was permitted up until Jan 2, 2020. So the transponder was likely on. With the GSL 71 off, the GDL90 would not broadcast the pressure altitude, but would still be broadcasting the Geometric Altitude (a form of GPS altitude). Unfortunately, the published GDL90 interface used by so many ADS-B portable receivers does not pass the Geometric altitude to the program interface, even when it was broadcast by the ADS-B Out system. Some receivers such as the Stratus and Sentry devices would receive the Geometric altitude, but the report does not state the ADS-B receiver equipment available on the Beaver.
 
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John Collins said:
The report did not state that the transponder was off, just that the GSL 71 was off. A GSL 71 is a control panel that interfaces to a GDL90. A GDL90 is an early UAT only version of ADS-B Out/In that was used in Alaska for the Capstone project that did testing on the ADS-B concept. The GDL90 is not compliant with the current ADS-B Out mandate, but was permitted up until Jan 2, 2020. So the transponder was likely on. With the GSL 71 off, the GDL90 would not broadcast the pressure altitude, but would still be broadcasting the Geometric Altitude (a form of GPS altitude). Unfortunately, the published GDL90 interface used by so many ADS-B portable receivers does not pass the Geometric altitude to the program interface, even when it was broadcast by the ADS-B Out system. Some receivers such as the Stratus and Sentry devices would receive the Geometric altitude, but the report does not state the ADS-B receiver equipment available on the Beaver.
Click to expand...

thank you
 
John Collins said:
The report did not state that the transponder was off, just that the GSL 71 was off. A GSL 71 is a control panel that interfaces to a GDL90. A GDL90 is an early UAT only version of ADS-B Out/In that was used in Alaska for the Capstone project that did testing on the ADS-B concept. The GDL90 is not compliant with the current ADS-B Out mandate, but was permitted up until Jan 2, 2020. So the transponder was likely on. With the GSL 71 off, the GDL90 would not broadcast the pressure altitude, but would still be broadcasting the Geometric Altitude (a form of GPS altitude). Unfortunately, the published GDL90 interface used by so many ADS-B portable receivers does not pass the Geometric altitude to the program interface, even when it was broadcast by the ADS-B Out system. Some receivers such as the Stratus and Sentry devices would receive the Geometric altitude, but the report does not state the ADS-B receiver equipment available on the Beaver.
Click to expand...
The otter had no transponder, just the GSL 71 UAT control head and ADS-B in and out. The GDL 90's were replaced by a FreeFlight ranger system that was gettto engineered to fit into the tray the GDL 90 used. With the GDL 90 the Chelton in the otter would have given an aural and visual alert. The FreeFlight system did not have this ability as it wasn't wasn't a feature listed by the FAA as part of the replacement contract. Still the otter would have had Randy on his screen. Of he had any kind of a scan going he should have seen the converging traffic on the EFIS.
 
That video was very well done.
 
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