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Midair Collision over Denver

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Re: Midair Collision over Denver

#121

Post by captainredbeard »

JohnJamesRambo wrote: post #88
nickcw wrote: post #7

Just in case anyone (like me) is thinking - wait did that aeroplane have a parachute? From: https://en.m.wikipedia.org/wiki/Cirrus_Airframe_Parachute_Sy... The Cirrus Airframe Parachute System (CAPS) is a whole-plane ballistic parachute recovery system designed specifically for Cirrus Aircraft's line of general aviation light aircraft including the SR20, SR22 and SF50. The design became the first of its kind to becom…

Thank you, I was so confused. I was thinking the pilot a genius for bringing and activating a parachute. Now I see it was just great design. > As of 1 May 2021, CAPS had been activated 122 times, 101 of which saw successful parachute deployment. In those successful deployments, there were 207 survivors and 1 fatality. No fatalities had occurred when the parachute was deployed within the certified speed and altitude p…

It’s a “marquee feature” of buying a Cirrus, he didn’t just wake up and pack a chute

Re: Midair Collision over Denver

#122

Post by selectodude »

captainredbeard wrote: post #119
qayxc wrote: post #81

Earlier quoted context omitted.

> The weight is so critical that the 7-seat plane can realistically only seat 4-5 adults. I think you overlooked an important factor there. The plane was indeed designed to realistically seat 7 adults. The issue is that in the 50 years since the plane was originally designed, the average weight of adults (in the US) increased by about 18% [0] and the average adult woman today weighs as much as the average adult man i…

Wrong - most singles can’t fill the seats and the tanks. This is general aviation 101 folks

Apparently normal humans weighed less than 150 pounds until we discovered McDonalds.

Re: Midair Collision over Denver

#123

Post by captainredbeard »

elliekelly wrote: post #99
tialaramex wrote: post #36

Earlier quoted context omitted.

Pilots of planes with CAPS are (now) taught to pull the chute if anything goes wrong inside the profile (low enough speed, far enough above ground) where the chute is designed to work. The aeroplane is insured, you can buy a new one. Even if the pilot and all passengers are insured you can't buy new ones. They changed this because it turns out that the same phenomenon that leads to private pilots taking undue risks i…

I’m not really sure how to ask what I want to ask, so apologies if this doesn’t make sense: Does the parachute only work if the plane is in a free fall? If the plane is gliding along and suddenly the engine goes out, for example, would pulling the chute work?

Well you wouldn’t pull the chute. The plane has lift when it has forward motion at a non stalling angle of attack. It would become a glider until reaching stall speed

Re: Midair Collision over Denver

#124

Post by captainredbeard »

throw0101a wrote: post #105
elliekelly wrote: post #99

Earlier quoted context omitted.

I’m not really sure how to ask what I want to ask, so apologies if this doesn’t make sense: Does the parachute only work if the plane is in a free fall? If the plane is gliding along and suddenly the engine goes out, for example, would pulling the chute work?

There is a maximum speed that the system can handle: > Four CAPS deployments occurred successfully at higher speeds, 168, 171, 187 and 190 knots indicated airspeed, and one deployment failed at an airspeed estimated at over 300 knots airspeed. * https://www.cirruspilots.org/Safety/What-Is-CAPS Anything lower than that will forward-motion stop the aircraft. AFAICT, there is a need for 2000' (650m) of altitude above th…

Even then, they recommend pulling the chute anyway because it can reduce velocity if it’s still above nominal “touchdown” speed

Re: Midair Collision over Denver

#125

Post by selectodude »

londons_explore wrote: post #109
JohnJamesRambo wrote: post #88

Earlier quoted context omitted.

Thank you, I was so confused. I was thinking the pilot a genius for bringing and activating a parachute. Now I see it was just great design. > As of 1 May 2021, CAPS had been activated 122 times, 101 of which saw successful parachute deployment. In those successful deployments, there were 207 survivors and 1 fatality. No fatalities had occurred when the parachute was deployed within the certified speed and altitude p…

They are some impressive numbers, but to really compare you need an expert looking at each situation and estimating the likely outcome had the CAPS system not been installed.

Most GA pilots are awful so it's a pretty safe bet that CAPS saved lives.

Re: Midair Collision over Denver

#126

Post by jeffreyrogers »

selectodude wrote: post #122
captainredbeard wrote: post #119

Earlier quoted context omitted.

Wrong - most singles can’t fill the seats and the tanks. This is general aviation 101 folks

Apparently normal humans weighed less than 150 pounds until we discovered McDonalds.

I think the average US soldier in WWII weighed less than 150. People were a little shorter then too though.

Re: Midair Collision over Denver

#127

Post by travisjungroth »

sokoloff wrote: post #112
travisjungroth wrote: post #108

Earlier quoted context omitted.

The point of the person you're replying to is that people have gotten bigger, which is a fact. Pointing out the comfort of levels of people in airplanes today doesn't dispute that. It used to be more common to have a flexible combination of seats/baggage/fuel. But pilots flip out (or crash) if they can't fill the tanks, every seat and the baggage compartment and come in under gross. So the same airplanes often don't…

Have you ever seen the optional 7th seat for a PA-32? It makes for 3-across in the back row which makes the backseat of a 911 look positively roomy.

I just looked at photos. Yes, it's very small.

Here's a Piper ad from 1966 with seven adults and their bags: https://i.imgur.com/fWyArRH.png

"The SIX will carry up to seven adults and their luggage - in real comfort"

And here's an ad from 1969 with six adults in it (and some rifles. a different time!) https://i.imgur.com/kGMrENf.png

I can't read into the minds of the engineers who made the airplane. Maybe it's true "I don't think they even imagined 6 adults as a typical cabin load". But we can see that the marketing department at least tried to make people think it was.

Re: Midair Collision over Denver

#128

Post by mannykannot »

omegant wrote: post #40
FatalLogic wrote: post #15

It's strange that the planes were supposed to be flying parallel and yet the damage to both planes in the photos suggests a collision at right angles Remarkable that the Metroliner held together, despite that terrible damage, and they landed it safely edit: interesting photo of the landing from the Reddit thread linked elsewhere https://imgur.com/gallery/yKPOWR0

Looking at the youtube video of the radar with the radio sound that someone posted below, the Cirrus is cleared to runway 17R but he turns to runway 17L. There are 3 possibilities : 1- he mistakes one runway for the other visually, 2- he wrongly thinks he is cleared for the 17L runway 3- or he makes a too wide turn going for the 17R, intruding the 17L area. The cirrus is the one that makes the mistake. The 17 runways…

> I understand that they were in different frequencies with different controllers.

If that is so, then it seems from the recording that the Metroliner pilot was only informed about the Cessna ahead of him and on approach to 17R, not of the Cirrus.

The Cirrus pilot is told about the Metroliner in an exchange that goes thus:

TWR: "Cirrus 6DJ, traffic you're following just turned right base there ahead and to your right at 6600', Cessna."

6DJ: "I have traffic in sight, 6DJ."

TWR: "Cirrus 6DJ, follow them, runway 17R, cleared to land. Additional traffic north shore, it's a Metroliner for the parallel runway."

6DJ: "Traffic in sight, cleared to land 17R, 6DJ."

Now, does that second "traffic in sight" refer to both aircraft, or only to the Cessna he had just been cleared to follow? It would be unambiguous if he had replied "two in sight", but if, for whatever reason, the mention of the Metroliner (in the same call as the clearance was given) had not registered, the Cirrus pilot would not have been aware that more than one other aircraft needed his attention. And if the Metroliner communication was being conducted on a different frequency, neither pilot would have had any other opportunity to become aware of the other airplane, except by seeing it - and, in addition to the Metroliner pilot presumably being in the left seat, the Cirrus was banked right, turning final, and one might guess its pilot was probably looking at the runways and/or the Cessna ahead.

Putting this together, I suspect the Cirrus pilot never registered the presence of the Metroliner until the collision - and I doubt the Metroliner pilot saw the Cirrus even after the collision, given that he thought he had an engine failure (he might have seen it earlier, when it was heading north on downwind, and assumed it was behind him.)

This does not alter the fact that the Cirrus pilot overshot the 17R approach while turning onto final, and it is this which caused the collision. One other fact, pointed out by several commentators: the Cirrus was travelling at about 160 kts at the time, so any delay in turning final results in being out of position more quickly than in your average small, single-engined airplane.

Re: Midair Collision over Denver

#129

Post by boringg »

captainredbeard wrote: post #119
qayxc wrote: post #81

Earlier quoted context omitted.

> The weight is so critical that the 7-seat plane can realistically only seat 4-5 adults. I think you overlooked an important factor there. The plane was indeed designed to realistically seat 7 adults. The issue is that in the 50 years since the plane was originally designed, the average weight of adults (in the US) increased by about 18% [0] and the average adult woman today weighs as much as the average adult man i…

Wrong - most singles can’t fill the seats and the tanks. This is general aviation 101 folks

This sounds like backcountry tent sizing. 3-person tent! (Good luck fitting two people in there and anything else!)

Re: Midair Collision over Denver

#130

Post by phkahler »

azalemeth wrote: post #33
t0mas88 wrote: post #25

Earlier quoted context omitted.

The Cirrus overshot the centerline of the runway it was supposed to land on. The common way for these situations is for the plane to be on an intercept angle towards the centerline. That's a max 30 degree angle for an instrument approach, but this was a visual approach so it could have been a sharper angle. All it takes to make this mistake in a Cirrus (and other G1000 avionics type small airplanes) is to forget 1 bu…

Indeed. Something else I'd like to point out is that it might seem easy to 'blame the Cirrus' pilot or them call out for inattention, but doing so by itself isn't helpful. Aviation is so safe partly because it has managed to turn a culture of blame into a culture of continuous improvement and shared learning: I'd be very surprised if the airport's procedures came out of this unmodified, for example.

>> I'd be very surprised if the airport's procedures came out of this unmodified, for example.

I'm curious. The airport is at about 5900ft and they were at 6400. If that's AGL for them that seems like a long and high approach. If not, then they were going to do a 3 mile straight in at 500 feet AGL? Either interpretation doesn't fit my (limited, student) experience.

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