Not another 9/11 thread

[Capt. Manuvar]

I just want a bit of help on a few sept 11 issues that have been bothering me.
Airlnes operate under IFR which means they are always in radio contact (?). I lived in baltimore for about a year and i am slightly familiar with the airspace around there. There are three major airports in area of the pentagon: DCA, BWI and IAD , Loads of Class B.
I dont know much about the New york Airspace but i think its similar. SO

Were the four airliners maintaining prolonged radio silence and did anyone notice it?
If NO, then are there any recordings of ATC transmission with the highjackers?

If an aircraft deviates from it assigned altitude/course in such congested airspace, did anyone notice?

From the news reports, it seems action was only taken after the aircraft hit the WTC.
Does that mean that an airliner under ifr could divert (or could have diverted) from its assigned course and altitude , flown into busy New york/washington airspace while breaking speed restrictions without anybody noticing unusual radar contacts/dodgyor lack of comms?
I'm not trying to start any conspiracy theories, i just want to see it from an aviation professionals point of view
Capt. M

[av8boy]

Airlnes operate under IFR which means they are always in radio contact

IFR does not always mean constant radio contact with ATC. For instance, an aircraft landing at a remote location with no low altitude ATC radio coverage may be cleared for the approach and then instructed to change to advisory freq and cancel IFR via telephone. However, the aircraft which are the subject of this conversation would have been expected to be in radio contact with ATC throughout the duration of their flight.



Were the four airliners maintaining prolonged radio silence

Generally. There may have been, however, some conversation as well as an inadvertant keying of the mic on at least one.



and did anyone notice it?

Yes. Quickly.




are there any recordings of ATC transmission with the highjackers?

There are recordings from the appropriate freqs at the appropriate times.




If an aircraft deviates from it assigned altitude/course in such congested airspace, did anyone notice?

Yes.




From the news reports, it seems action was only taken after the aircraft hit the WTC.

Untrue. (However, it also depends upon what you mean by "action.")




Does that mean that an airliner under ifr could divert (or could have diverted) from its assigned course and altitude , flown into busy New york/washington airspace while breaking speed restrictions without anybody noticing unusual radar contacts/dodgyor lack of comms?

In a word, no, but it is more complex than that (is the transponder on, allowing for display of altitude/speed etc?). However, when the transponder and/or radio go away, it gets noticed. When the target goes in an unexpected direction, it gets noticed. When the target goes somewhere totally unreasonable, it really gets noticed. To the extent the position of the aircraft can be ascertained or estimated, ATC continues to protect for that aircraft regardless of where it goes.


Let's not do this again. OK?

Dave