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Re: Mid-air collision, Denver…

PostPosted:Thu May 13, 2021 7:39 am
by Josh
Worth noting that the 160 kt is almost certainly groundspeed.

KAPA has an elevation of 5900’ and assuming still wind that gives an IAS more in the 140 kt region. Still pretty rapid for a circuit in a notoriously slippery aircraft!

Re: Mid-air collision, Denver…

PostPosted:Thu May 13, 2021 7:42 am
by Jonzarno
This was posted on COPA. The consensus there is that the Cirrus was way too fast in the circuit and overshot the runway centre line into the path of the other aircraft which was landing on the parallel runway.

The angle of bank in the Cirrus would have been steep enough for the pilot not to be able to see the other aircraft.

The reference to “first solo” is to the pilot of a 172 who was indeed on his first solo, was in the circuit at the time and not to the Cirrus pilot.

It is amazing that neither pilot was killed.


Re: Mid-air collision, Denver…

PostPosted:Thu May 13, 2021 7:43 am
by IMCR
johnm wrote:EC completely irrelevant to this my guess is that the Cirrus pilot was transferring from a slower aircraft and simply got behind.


What does this mean?

As I said earlier 7.1 has only been mandatory for the last 5 years on older cat in europe but not in the US.

This reminds me of the days Dijon operated bisecting runways on different frequencies (one military, one civil). It was unbelievably dangerous with a varied mix of GA, CAT, and fast military jets.

100 knots turning base and decreasing is about right.

Re: Mid-air collision, Denver…

PostPosted:Thu May 13, 2021 7:47 am
by johnm
It means that pilots were aware of each other's presence from traffic information and the Cirrus pilot barrelling down the base leg at least 20 to 40 KIAS faster than most light aircraft at that point simply turned final too late.

Re: Mid-air collision, Denver…

PostPosted:Thu May 13, 2021 7:49 am
by IMCR
No I meant transferring from slower aircraft?

Re: Mid-air collision, Denver…

PostPosted:Thu May 13, 2021 7:55 am
by PeteSpencer
TheATC tape is available from VASA aviation : no transmissions from the Cirrus after the MAC: plenty from other a/c witnessing chute deploy and correctly identifying a mid-air.

The pilot of the twin remains amazingly calm, initially diagnosing engine failure.

Then calmly lands and taxies to ramp without even mentioning that his a/c has nearly been chopped in half.

Cool or what? :wink:

Re: Mid-air collision, Denver…

PostPosted:Thu May 13, 2021 8:00 am
by G-BLEW
Full Metal Jackass wrote:
IMCR wrote:Most modern transponders now automatically apply ground mode.


That's what I thought hence I would put the transponder to ALT mode after starting the engine; the transponder is a GTX330 ES; even though the ground speed was set properly to ensure it logged flight time, it was still sufficient to cause a TCAS RA.

I didn't understand it either, still don't, but only put the transponder onto Alt mode after lining up.....


When I had a 330ES I am pretty sure it turned on automatically in GND mode, and switched, again automatically, to ALT on reaching (IIRC) 40kts. No manual intervention needed from me in normal use.

Ian

Re: Mid-air collision, Denver…

PostPosted:Thu May 13, 2021 8:19 am
by riverrock
VAS Aviation doesn't have the Cirrus being called to the metroliner, but a Cessna ahead is? The metroliner is called to the Cirrus.


The two aircraft are on different frequencies, and LiveATC record both within the same stream, so one broadcast may be covered by the other, so this isn't definitive.

Re: Mid-air collision, Denver…

PostPosted:Thu May 13, 2021 8:26 am
by riverrock
Transponders can only switch if they have some sort of speed information, speed switch or weight on wheels reference. For example, the popular Trig TT21 needs ground/air info wired to it to automatically switch. Most small GA doesn't have that.

Re: Mid-air collision, Denver…

PostPosted:Thu May 13, 2021 8:27 am
by johnm
IMCR wrote:No I meant transferring from slower aircraft?


The Cirrus was owned by a school so I suspect the pilot was under differences training and more used to the speed of Pipers or Cessnas than Cirruses

Re: Mid-air collision, Denver…

PostPosted:Thu May 13, 2021 8:35 am
by IMCR
If accurate the radar trace is very interesting looks like the Cirrus was turning away from the Metro as it rolled out onto final so the Metro was always slightly behind in the Cirrus’s blind spot until the collision. The Metro probably had the best chance of seeing the other aircraft but again pretty much in its blind spot given eyes very much forward and on the runway.

Re: Mid-air collision, Denver…

PostPosted:Thu May 13, 2021 8:50 am
by skydriller
johnm wrote:the Cirrus pilot barrelling down the base leg at least 20 to 40 KIAS faster than most light aircraft


Im uncomfortable with this evocative statement. 3nm (quoted as accident point is quite a long way from the threshold. I personally dont consider this a "base" position for a circuit - its outside a UK ATZ after all.

*Edit : What is the usual "base" speed for a Cirrus and would it habitually be at 3nm as opposed to closer?

riverrock wrote:The two aircraft are on different frequencies


This I do find odd though, why would that be for 2x aeroplanes 3nm from the threshold of an airport? At what point would Approach switch to Tower? Is it clear yet what flight rules the two aircraft were operating under?

Regards, SD..

Re: Mid-air collision, Denver…

PostPosted:Thu May 13, 2021 8:54 am
by Iceman
PeteSpencer wrote:The pilot of the twin remains amazingly calm, initially diagnosing engine failure.

Then calmly lands and taxies to ramp without even mentioning that his a/c has nearly been chopped in half.

Cool or what? :wink:


If you look at the twin’s flight on FR24 (the reg is in the pictures), you can’t even discern the point of impact on the approach and, as you say, he does taxi to the ramp.

Iceman 8)

Re: Mid-air collision, Denver…

PostPosted:Thu May 13, 2021 8:56 am
by johnm
Im uncomfortable with this evocative statement. 3nm (quoted as accident point is quite a long way from the threshold. I personally dont consider this a "base" position for a circuit - its outside a UK ATZ after all.


A 2nm ATZ is fine for a Tiger Moth but a bit tight for a more modern aeroplane :twisted:

Re: Mid-air collision, Denver…

PostPosted:Thu May 13, 2021 9:01 am
by G-JWTP
PeteSpencer wrote:TheATC tape is available from VASA aviation : no transmissions from the Cirrus after the MAC: plenty from other a/c witnessing chute deploy and correctly identifying a mid-air.

The pilot of the twin remains amazingly calm, initially diagnosing engine failure.

Then calmly lands and taxies to ramp without even mentioning that his a/c has nearly been chopped in half.

Cool or what? :wink:


When he/she climbed out of the Metroliner and had a look at the outside, then that was probably the 'brown trouser moment'.

G-JWTP