Key Lime Air Swearingen SA-226 Metro II and Cirrus SR-22 mid air collision

[aviatoreb]

2 hours ago, A64Pilot said:

Most of transport aircrafts strength is in the floor so that it can handle cargo and people, that floor as well as carrying the weight has to also restrain those people and cargo so it’s pretty tough, the rest of the fuselage’s primary job is be a pressure vessel and aerodynamics, but I imagine an aircraft with overhead baggage compartments has to be a whole lot stronger, case that’s a lot of weight, and the design loads are quite high. I assume the Metro liner has no overhead baggage?

Clearly you are right.

But I presume the reason such a large chunk tore away from the body after an impact with a smaller airplane that the smaller airplane was not destroyed to smithereens meaning that must have been a glancing blow so not a huge amount of force, 

is it must be a blow to a tensioned material like tapping an egg on its side with a load on it from above - even a relatively lighter point force will result in a large caving of the structure.

And Toto - I agree with your assessment - that thankfully this was all while at slower speeds or the aerodynamic with part of the body removed would have made huge forces.

That said - anyone remember that catastrophic pressurization failure on a Hawaiian passenger flight a number of years ago where a big piece of the fuselage tore away leaving an open top ride for the happy passengers inside - and that thing was moving at jet speeds but still survive to the landing.

https://www.aerotime.aero/18542-history-hour-aloha-airlines-flight-243-incident

[EricJ]

5 hours ago, midlifeflyer said:

I wondered. Assuming we used the same source (I use https://aspm.faa.gov/opsnet/sys/Airport.asp) at first I thought you might have pulled up 2020 when I would expect a reduction  in the numbers. That's why I used 2019. Then I pulled up 2020 and found that, as a GA airport, APA still had over 300,000 ops while the commercial airports were down, moving it to #8 of all US airports. (DVT was #5!)

Wow, Van Nuys has dropped way down.   They're usually right up there with DVT.

A year or so ago at our annual pancake breakfast at the wash rack, the DVT airport manager said that DVT had passed PHX (Sky Harbor) for total operations.   I didn't previously realize how far up the list APA is.   #2 for GA airports, it looks like!

[midlifeflyer]

3 hours ago, EricJ said:

Wow, Van Nuys has dropped way down.   They're usually right up there with DVT.

A year or so ago at our annual pancake breakfast at the wash rack, the DVT airport manager said that DVT had passed PHX (Sky Harbor) for total operations.   I didn't previously realize how far up the list APA is.   #2 for GA airports, it looks like!

VNY, APA, and DVT have flip-flopped in the top 3 or 4 for many years. Don't use 2020 as much of an indicator for anything representative.

[aviatoreb]

1 minute ago, Hyett6420 said:

My take on this Eric is that it was the cirrus wheels that cut the fueslage, if you look at the shape of the cut, it seems to make sense.  The speed of the cirrus coupled with the rigidness of the undercarriage would have created two nice knives.  

That sounds right.  But still if the skins were not under tension, I would have guessed that the skins would either tear right there, or maybe just dent.  That it tore away a big section like that suggests to me that it was all a big tensioned piece.

[RJBrown]

9 minutes ago, aviatoreb said:

That sounds right.  But still if the skins were not under tension, I would have guessed that the skins would either tear right there, or maybe just dent.  That it tore away a big section like that suggests to me that it was all a big tensioned piece.

Yes,

They are called a stressed skin or Monocoque design. Our Mooneys fuselage is built that way behind the steel cage. Cessnas are that way for the entire fuselage. The formers and the stringers give it shape but the skin is a lot of the strength. This is described and contrasted in car construction here: https://www.motortrend.com/news/body-on-frame-vs-unibody-vs-monocoque-what-is-the-difference/

[A64Pilot]

Not meant to pick but most aircraft are Semi-Monocoque meaning that there is structure other than the skin, formers, stringers, ribs etc. Monocoque is when there is just the skin.

One extreme is a fabric covered airplane where the skin is no structure, and Monocoque is the other extreme where the skin is 100% of the structure.

In Monocoque construction a dent can be a serious issue, it can cause the whole thing to fail.

[GeeBee]

Another mid air collision involving a Cirrus

https://www.avweb.com/aviation-news/just-days-after-centennial-miracle-another-midair-and-another-caps-pull/

[KB4]

On 5/13/2021 at 8:52 AM, ragedracer1977 said:

How do you see and avoid traffic behind you?

With good situational awareness. Ads-b Traffic screen and radio calls would have identified the Cirrus and put you on notice you ain’t alone approaching the field.  Traffic on FF even changes colors as you get closer so even if there are many targets on the screen you can quickly ignore the distant targets. 

[EricJ]

2 hours ago, GeeBee said:

Another mid air collision involving a Cirrus

https://www.avweb.com/aviation-news/just-days-after-centennial-miracle-another-midair-and-another-caps-pull/

The Cirrus in that report was evidently not involved in a mid-air collision.

[GeeBee]

That is correct, but another CAPS pull none the less

I would like to know how many of the CAPS pull involved a flyable airplane. IOW, fuel mismanagement etc. The idea of "pull early" may be overstating the "saves".

 

 

[MooneyMitch]

On 5/15/2021 at 1:33 PM, midlifeflyer said:

Don't use 2020 as much of an indicator for anything representative.

Except the Dodgers won the World Series!!

[Hank]

1 hour ago, MooneyMitch said:

Except the Dodgers won the World Series!!

You just made his point about 2020 not being a representative year . . . .

[MooneyMitch]

10 hours ago, Hank said:

You just made his point about 2020 not being a representative year . . . .

Hey, watch it mister!!   

[ragedracer1977]

16 hours ago, KB4 said:

With good situational awareness. Ads-b Traffic screen and radio calls would have identified the Cirrus and put you on notice you ain’t alone approaching the field.  Traffic on FF even changes colors as you get closer so even if there are many targets on the screen you can quickly ignore the distant targets. 

The traffic was never called to the metroliner. It was behind him, and the controller did not have to call it out.  He was on a different frequency.

If you land at airports with parallel runways, you get traffic alerts all the time. You EXPECT an airplane to be very close to you on final, and by the time it hit you, it's too late to do anything.

[Browncbr1]

Gtn visual approach is a great tool for confirming you’re lined up for the correct runway at unfamiliar airports ...   

[flyboy0681]

29 minutes ago, Browncbr1 said:

Gtn visual approach is a great tool for confirming you’re lined up for the correct runway at unfamiliar airports ...   

And a glideslope to boot.

[N201MKTurbo]

I have been working with a man for the last few days who worked for Swarengen for 20 years. His jacket has a metro liner embroidered on the back.

I showed him the picture and he said if the Cirrus would have hit 6 inches further back the tail would have come off.

[ilovecornfields]

Aviation News Talk had an interesting podcast on this. Their theory was that the Cirrus guy was using his AP to do his base-to-final turn and made a perfect 2 minute turn right into the metroliner. They hypothesized that if he'd made a 30 degree banked turn or actually been at the proper speed this would have never happened but due to his groundspeed, a standard rate turn was about 18 degrees and it arced perfectly into the metroliner.

Seems like this should be a pretty easy theory to prove or disprove.

https://aviationnewstalk.com/podcast/188-nine-lessons-from-cirrus-midair-collision-over-denver/

Edited May 27, 2021 by ilovecornfields