WTC Destroyed by Aviation Accident

Delta Force

Banned
What if one of the towers of the WTC had been destroyed in a terrible aviation accident instead of by terrorist attack, suppose by an aircraft suffering mechanical failure crashing trying to land at JFK International? What kind of an impact would this have on national culture and the aviation industry? What kind of an impact would this have on building codes and the handling of aircraft in crowded population centers?

Also, how would the rebuilding of the WTC be carried out in this timeline with half of the complex still standing and one of the towers being destroyed in a terrible accident? Would the remaining tower be demolished due to the proven design flaws of the complex or would it be possible to retrofit a repair? Might it not even matter at all, an aviation crash into a building being a rather rare event?
 
IIRC the WTC was designed with the possibility of an aircraft impact in mind, however the assumptions the architects made was that the such an aircraft would be trying to make an emergency landing and would be moving slowly and low on fuel. However on 9/11 the planes were nearly fully fueled and travelling at full throttle so there was more energy in the initial impact and more fuel to feed the subsequent fire which was what caused the structure to fail, the fact both towers lasted as long as they did allowing thousands to escape shows just how good the design was.

As for the consequences obviously it would still be a terrible tragedy but not on the same scale as OTL, if the Tower survives it is going to be extensively damaged and may not be repairable. That does raise the question as to how you dismantle or demolish something that size in a controlled way.
 
Also, how would the rebuilding of the WTC be carried out in this timeline with half of the complex still standing and one of the towers being destroyed in a terrible accident? Would the remaining tower be demolished due to the proven design flaws of the complex or would it be possible to retrofit a repair? Might it not even matter at all, an aviation crash into a building being a rather rare event?

I think I'll just address the second portion since aircraft have been flying into buildings ever since they got off the ground.

The demolition of the remaing tower would be contingent upon the structural damage it received with the collapse of the other. Given the extent of damage received by other buildings, at least two buildings were subsequently demolished as being unsafe IIRC, in the WTC complex one would likely consider that retrofitting it would be more expensive and dangerous to accomplish than slowly and deliberately taking it apart.
 
What if one of the towers of the WTC had been destroyed in a terrible aviation accident instead of by terrorist attack, suppose by an aircraft suffering mechanical failure crashing trying to land at JFK International? What kind of an impact would this have on national culture and the aviation industry? What kind of an impact would this have on building codes and the handling of aircraft in crowded population centers?

Note that this almost happened in 1981 (dense fog + pilot error).
It certainly would have changed the outcome of the air-traffic controller's strike, (there's no way Reagan could fire them after such a disaster) and would have prolonged the recession (you'd have to cordon off Lower Manhattan for a year until they could safely demolish the other tower), which might mean Reagan does not get re-elected.

https://www.alternatehistory.com/discussion/showthread.php?t=77535

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Well a B 25 crashed into the Empire State Building during WW 2. When the Trade Centers were being designed they were supposed to be able to handle a hit by a 707. That was the largest jet liner at the time. As mentioned before the assumption was it would be low and slow and out of gas. The planes that hit the towers were bigger then the 707. Also they were not going low and slow and out of gas.
docfl
 
An accidental collision, let alone one severe enough to take down one of the towers, is highly unlikely due to the use of airspace around lower Manhattan. In good weather with the right winds, the approach up the Hudson and the airspace therein is reserved for flights landing at LaGuardia runway 13. They fly northeast up over the river and make a right turn to land at LGA; large planes bound for JFK or EWR are nowhere near the area. Theoretically, an extended ILS approach to JFK's runway 13L would take planes over lower Manhattan. However, there is no such approach; the ILS is to 13R and there is no extended approach over Manhattan, as such a pattern would conflict with traffic heading into Newark and departing LaGuardia. Instead, planes are vectored over Brooklyn to TELEX intersection, about 8 miles from the runway. Moreover, all planes in that airspace are under radar control and modern aircraft have navigation capabilities that make such a large error highly improbable. To get a plane that far off course, you'd need a combination of both a ground control radar failure and an on-board navigation system failure. You can construct a scenario of cascading failures that gets you there, but it isn't very likely and gets less likely the larger and more complex the aircraft is.

The second part of the problem is that an aircraft that off-course is not under any reasonable scenario going to be flying anywhere near as fast as the 9/11 planes. There's a 250 knot speed limit below 10,000 feet in the US (a byproduct of the 1960 midair collision over Staten Island). As I recall, the 9/11 planes hit the towers at speeds of around 500 knots for UA175 and 400 knots for AA11, far faster than any scenario involving an accident. Since momentum is mass times velocity, the momentum of an accident aircraft is going to be something around half that of the 9/11 planes if one assumes a speed of 200 knots (230 mph). Less momentum at impact = less damage. Now, I suppose you could create a scenario with a just departed intercontinental flight, loaded with even more fuel than the 9/11 planes and an even larger aircraft, say a 747-400 headed for Tokyo, that develops an emergency after takeoff and winds up hitting one of the towers with the same momentum as one of the 9/11 planes, but this is really a stretch. Possible? Perhaps. But it's like a one in a billion scenario of cascading failures and mistakes that is really hard to imagine actually happening. If it did, it would be regarded, rightly, as a fluke accident.
 
An accidental collision, let alone one severe enough to take down one of the towers, is highly unlikely due to the use of airspace around lower Manhattan.

There was a near-miss in 1981: an Aerolineas Argentinas 707 randomly descended to 1500 feet in dense fog, and began an unapproved landing approach for JFK, on a vector that would have hit the North Tower's radio mast.

Granted, a collision with the mast would have left the plane scattered across Brooklyn, not inside the WTC ; but since the pilot was ignoring controller instructions anyway, he could have just as easily descended to 1200 feet (or whatever the TCA floor was in 1981) instead of 1500.
 
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