Thanks for all that information about mode-3 transponder combinations, etc.
> XFSUgimpLB41X, I just got this ICOM R-2 receiver (it's smaller than a pack of smokes) for a birthday gift from my girlfriend on Nov 16. Since then, I've only had time to visit Toronto International Airport 2 times with the last visit being a month ago (it's only a 25 minute drive on the highway, but I've been very busy). While I was at Toronto Intl, I could hear everone perfectly...the ATC controllers for arrival, departure, the tower and ground were loud and clear.
Although I wasn't concentrating on the 4 and 3 digit numbers I hear pilot's saying during their readbacks to approach when I was last at YYZ (I was busy reading my new toy's manual), I know that I never heard the word "squawk" used once by anyone.
To answer your question, I will be going out to YYZ tonight or in the morning so I can really listen to the controller's instructions. Also, yes sir, I am hearing the numbers right. I have perfect hearing and the reception on this receiver is excellent!
> AAR90, thanks for that great info about why and when a pilot's transponder code might be changed by ATC during flight.
> > > OK, here we go again. Let's see if the following info can shine any light on this 4 digit question (I'm thinking of changing my user name to "4 DIGITS"
Last night and this morning I sat back with my girlfriend (who's also an A.Net member) and listened to the pilot's readbacks after checking in with Toronto's arrival controllers.
Starting at 9:20 pm (Jan 10, 21:20 hrs, Toronto time) I heard the following 4 digit numbers read back by 5 different pilots checking in over a 4 minute period.
In order of pilot's readback.
Several pilots checking in didn't readback any codes other than their flight #.
Between 9:30 and 9:40 pm, 5 different aircraft's pilots read back the same 4 digit code...2970.
These airliners were mostly Air Canada, however some others were American Airlines, Jazz, US Air, as well as a medivac flight. I couldn't pick up the names of many of the airlines checking in because of the pilot's lingo being too quick!
Here's some in detail.....(Jan 10, 22:05 hrs local time) "Good evening Toronto, Northwest one four eight eight's with you at one one thousand, speed showing two fifty knots, with whiskey".
His readback...."two niner six niner, down to seven thousand, Northwest one four eight eight".
This morning (Jan 11, 10:35 hrs local time) I heard this pilot's transmision..." Good morning Toronto, Air Canada seven three three's with you at one one thousand, coming at you at two fifty knots with xray.
His readback...."OK, twenty four right, one zero niner four, air canada seven three three".
A readback code at 11:20 this morning for Air Canada 579 was 2984. Another for Air Canada 555 at 11:28 am was 2985.
That's all folks. I wish I could record these pilots and post an audio, that would surely help. I'm very aware that some of these codes could be an altimeter setting...such as 2985, but, what about 1094, 1832 or 7362?
Incase you guys have had enough of this question about these mysterious 4 digit readbacks, here a quick question that I think I know the answer to, but want to make sure.
Sometimes I've heard pilots say during their readbacks "OK, we've got 5 on the glideslope" I've also heard 4 and 3 "on the glideslope".
Are these pilots simply being told how many aircraft are currently flying down the ILS?