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Question re hypothetical midair collision

Old 11-07-2022, 06:30 PM
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Default Question re hypothetical midair collision

This question came to me, and I don't know whether it has been addressed before or elsewhere. I don't want to be macabre, so I suppose you could substitute "a bird" for the 152.

Hypothetical scenario:
737 Departs JFK on a flight to MIA.
Upon approach to MIA, 737 collides with a Cessna 152 midair. Everyone miraculously survives.
Two passengers just missed the 737 flight from JFK, and marvel at how lucky they were to have missed the flight.

Hypothetical analysis:
If the two potential passengers had not missed the flight, the 737 would have, by a miniscule amount, a longer takeoff roll, since it is .23% heavier.
The 737 would see very slightly different winds, have a different fuel burn rate, different control input responses, etc.
After multiplying all of these tiny differences over 1100 NM, what are the chances that the planes would have been in the same place at the same time over MIA ? At 250 knots, if the 737 arrives at the collision spot .1 second earlier or later, it misses the 152 (40 feet displacement).

I'm waiting for minds greater than mine to figure this one out.
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Old 11-07-2022, 06:46 PM
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That could be plausible, however to my mind its really just the butterfly effect. What if one of those passengers had a lithium battery that got a thermal runaway on the taxi out and they returned to gate? What if that same thermal runaway happened during rotation and they burned through some wires/control systems before returning to field? I could probably think of hundreds of other variables based on 2 late passengers.

There are millions of variables on every single flight, many of which could drastically change the outcome of the flight. SMS data does a great job at targeting the major threats and weaknesses and 2 late connecting passengers probably never shows up on that dashboard. In this case of a 737 vs 152 midair, the first things that run across my mind are where was ATC, ADSB, TCAS RA, and visual see and avoid protocols in this circumstance.

Not to be a jerk but, why focus on this one specific variable of a hypothetical?
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Old 11-07-2022, 06:51 PM
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Why would the 737 "see very slightly different winds," regardless of whether two passengers are aboard, or not? The weight of the two passengers is less than the tolerance in the fuel system indication and the APU fuel burn, and becomes entirely inconsequential with respect to length of taxi or any other delays; the airplane may well burn more fuel than their weight; or may burn less. If the 1,000 lbs of fuel burn is assumed for takeoff and the aircraft burns 500, then it's already made up the difference in weight of passengers.

Because the takeoff numbers are spelled out in values that won't reflect a difference with the weight of the two passenger(s), their presence is inconsequential. Two passengers will not require a different flight level.

There's a lot one can do to end one's life early, but when it's your time, you're done.

Perhaps a more useful question might be what would have occurred had the occupants of the 152 elected to take a train to JFK and hop that 737 back to Miami.

Then the collision would have occurred between the 737 and some doctor in his Bonanza. It would still happen to the two occupants of the 152, and everyone on board the 737. Plus one of the two who missed their flight at JFK. He'd be crushed in a tragic escalator mishap on the way back out to the parking lot, and the other one would slip and fall in the restroom, striking his head on a soap dispenser. Karma is an ungrateful sod, and one determined *****.
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Old 11-08-2022, 02:42 AM
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The 737ís speed and position on approach to MIA were largely determined by ATC and the traffic in front of it. An extra 400lb of weight would make a measurable difference in many parameters if you cared enough to measure it, but itís not going to change it enough to alter the planes place in line with Miami approach.

Even setting aside that there are many small factors affecting aircraft performance, this isnít a case of sensitive dependence on initial conditions. There are a number of step functions (ie ATC) that substantially reign in small variations. This isnít newtonian ballistics
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Old 11-08-2022, 03:10 AM
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I find myself wondering what kind of hobbies the OP has(?).
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Old 11-08-2022, 04:26 AM
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There is a difference between academic and practical.
Pick a random single digit number and start dividing by twoÖ.youíll mathematically never reach zero.
For all practical intents and purposes you will.
Have you ever done anything around the house as far as DIY handyman stuff?
You measure 2 3/4 inch on a non calibrated measuring tape that you bought at Home Depot.
Does it matter if itís 2.75000000000 inch exactly or 2.7532568? Or roundabout 2 3/4?
Cut it with a saw with a thickness of about 1/10th of an inch?
What if the ATC controller took a swig of coffee and delayed the take off clearance by a second.
Brah itís a useless scenario and I want my 182 seconds back that it took to type the answer.
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Old 11-08-2022, 06:37 AM
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Itís the butterfly effect, not the 152 effect. Lots of inherently improbable things happen every day. Eventually someone (probably not me) will win Powerball.
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Old 11-08-2022, 10:09 AM
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Those two passengers who missed the flight sound like people who would be fumbling around in the overhead bin causing a delay in the "cabin secure" call from the flight attendants which would have taken an extra 10 seconds to complete the before takeoff checklist which in turn would have resulted in the crew telling ATC to "standby we need to finish a checklist" before accepting the takeoff clearance which would have caused a two minute delay as they waited for the Delta A320 on short final to land an clear the runway which would have resulted in them missing the C152.

Unfortunately after missing the C152 that two minute delay placed them right in the path of an 87 year old who was 13 years out of his medical and was single piloting a King Air and who mistakenly made his downwind to the wrong airport thus collided with the 737 and everyone died.
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Old 11-09-2022, 04:23 AM
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And thatís basically the promise of the next ďFinal DestinationĒ movie. Well done!
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Old 11-13-2022, 04:44 PM
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Originally Posted by maxru View Post
And thatís basically the promise of the next ďFinal DestinationĒ movie. Well done!
Ha! I read the first post was just scrolled through to see if someone mentioned Final Destination. I almost got there but you beat me to it! lol
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