"Say Altitude"

[PGT]

When departing towered airports I notice that every other time or so I get asked what altitude I'm at soon after departure, usually about 500-800 AGL. Now, I always set the transponder to ALT from standby when I taxi onto the runway so that can't be it. I never forget to set the altimeter either.

It's usually

T: Cherokee 190 say altitude
M: passing 1,XXX. 190.
sometimes they come back and say ok or thank you.

and that's where it ends

[Ian J]

Just an educated guess, but I belive they are using it to positively identify you - and to verify your transponder.

[ElyJs]

Yea a guess from me here too, but something about a spacing issue. Once your altitude and transponder are confirmed they can reduce the spacing. I am sure someone can chime in with a more qualified sourced response.

-Jason

[fish314]

There's an old piece of aviation humor that starts like that;

ATC: November 1234 say altitude
N1234: Altitude
ATC: November 1234 SAY ALTITUDE!!!
N1234: ALTITUDE!!!
ATC: November 1234 Say "Cancel IFR"

N1234:.... Uh, we're passing 4,500 for 6000, sir.

[Bumblebee]

I believe they do this to confirm that the altitude displayed on your altimeter is close (within 200') to what they are showing.

[PGT]

Originally Posted by fish314

There's an old piece of aviation humor that starts like that;

ATC: November 1234 say altitude
N1234: Altitude
ATC: November 1234 SAY ALTITUDE!!!
N1234: ALTITUDE!!!
ATC: November 1234 Say "Cancel IFR"

N1234:.... Uh, we're passing 4,500 for 6000, sir.

I might have have to do this once

[rickyrhodesii]

The controller needs to validate your mode C readout. It's considered valid when the altitude varies less than 300'.

One way to avoid being asked on departure is to say, "Departure, Cherokee 190 (passing) 800 for 2,000 (assigned altitude or VFR cruising altitude)." You're telling the controller your altitude, so he can validate it without asking you.

[tgrayson]

Originally Posted by rickyrhodesii

You're telling the controller your altitude, so he can validate it without asking you.

This should be done for every new facility you encounter, according to the AIM. For handoffs within a particular facility, just your assigned altitude.

[Bumblebee]

Originally Posted by rickyrhodesii

The controller needs to validate your mode C readout. It's considered valid when the altitude varies less than 300'.

Thanks, I thought it was 200' . . .

[Fox Xray]

Originally Posted by rickyrhodesii

The controller needs to validate your mode C readout. It's considered valid when the altitude varies less than 300'.

One way to avoid being asked on departure is to say, "Departure, Cherokee 190 (passing) 800 for 2,000 (assigned altitude or VFR cruising altitude)." You're telling the controller your altitude, so he can validate it without asking you.

[flyguy]

Originally Posted by fish314

There's an old piece of aviation humor that starts like that;

ATC: November 1234 say altitude
N1234: Altitude
ATC: November 1234 SAY ALTITUDE!!!
N1234: ALTITUDE!!!
ATC: November 1234 Say "Cancel IFR"

N1234:.... Uh, we're passing 4,500 for 6000, sir.

Controllers pull this stuff sometimes too. I was with a student once, and after a complicated instruction to enter the traffic pattern he asked the controller to "say again please" to which the controller replied "again please". I've been waiting for the time when I miss a radio call to come back and say "Uh, sorry I was on the land line.....". Gotta make sure the controller is pretty cool though.

[ClearedToThe]

Not sure if it applies to your situation, but not all towers have radar (i.e. most Class D). Thus the only way to know your altitude is for them to ask.

Also some facilities do not have radar coverage to the ground, so ATC (in this case a TRACON or ARTCC) asking for your altitude is the only way they know where you are at until you are "radar contact".

[TonyWilliams]

I might add that if you're climbing out at 5000 fpm, you might lag the altitude report slightly.

Otherwise, it'll never be within 300 feet of the mode C (which only updates with the speed of the radar antenna... 6 second approach, 12 seconds center).

Also, if you're in a mega slow climb (like 500fpm or less), if you're talking to center and get within 250 feet of your assigned altitude.... you're level. The center computer software stops displaying mode C within 300 feet of your final assigned altitude.

As a side note, Alaska Airlines used to (maybe still?) take advantage of this feature by letting the plane drift up or down 200 feet in level flight.

If your mode C is off by over 300 feet, the controller is supposed to tell you, "altitude differs by more than 300 feet, stop altitude squawk."

[trafficinsight]

Originally Posted by flyguy

Controllers pull this stuff sometimes too. I was with a student once, and after a complicated instruction to enter the traffic pattern he asked the controller to "say again please" to which the controller replied "again please". I've been waiting for the time when I miss a radio call to come back and say "Uh, sorry I was on the land line.....". Gotta make sure the controller is pretty cool though.

We were doing practice approaches once and the controller was doing fine and then all of a sudden didn't respond to like two or three calls. Finally we asked for a radio check and I swear to you she said "Sorry, something was coming in my ear."

silence on the frequency.

[Wolfy]

At a 40' MSL airport:
0HF, say altitude
1000 feet, 0HF
0HF, you're displaying 900 ft. below sea level.
Uh, 0HF is turning off our transponder.

[eagledriver101]

Originally Posted by fish314

There's an old piece of aviation humor that starts like that;

ATC: November 1234 say altitude
N1234: Altitude
ATC: November 1234 SAY ALTITUDE!!!
N1234: ALTITUDE!!!
ATC: November 1234 Say "Cancel IFR"

N1234:.... Uh, we're passing 4,500 for 6000, sir.

ROFLMAO

[flyguy]

Originally Posted by Travisimo

At a 40' MSL airport:
0HF, say altitude
1000 feet, 0HF
0HF, you're displaying 900 ft. below sea level.
Uh, 0HF is turning off our transponder.

Okay I've got a "squawk altitude" story.

A cop who was a student pilot was on his first solo cross county. His instructor failed to teach him about mode C transponders. So he's cruising along at 7500 feet and ATC asks him to squawk altitude. He thinks to himself "hmmm....squawk altitude??...okay I'm at 7500 feet so 7-5-0-0." After a few moments ATC asks if everything was okay - "affimative" he answers. Another few moments pass and they ask him if there is a firearm on board. He thought is was a strange question, but he was a cop, and happened to be carrying his weapon, so he answered "affirmative". The national guard was waiting for him at his destination.

[eagledriver101]

Originally Posted by flyguy

Okay I've got a "squawk altitude" story.

A cop who was a student pilot was on his first solo cross county. His instructor failed to teach him about mode C transponders. So he's cruising along at 7500 feet and ATC asks him to squawk altitude. He thinks to himself "hmmm....squawk altitude??...okay I'm at 7500 feet so 7-5-0-0." After a few moments ATC asks if everything was okay - "affimative" he answers. Another few moments pass and they ask him if there is a firearm on board. He thought is was a strange question, but he was a cop, and happened to be carrying his weapon, so he answered "affirmative". The national guard was waiting for him at his destination.

Uhh ooops!

[GreenDayPilot]

Originally Posted by fish314

There's an old piece of aviation humor that starts like that;

ATC: November 1234 say altitude
N1234: Altitude
ATC: November 1234 SAY ALTITUDE!!!
N1234: ALTITUDE!!!
ATC: November 1234 Say "Cancel IFR"

N1234:.... Uh, we're passing 4,500 for 6000, sir.

This happened to one of our guys from Taiwan.... just about the funniest thing I've heard on ATC.... cracked me up!