Question for controllers out there

[asgcpa]

On Sunday flying back into the Chicago area, I was worried about the ORD Bravo. There is an area where Bravo starts at 1900 feet, so because it was bumpy I tried to stay at 1700 feet, but that is a little low for my liking if I am not in a pattern. If you trim for 1800 feet, and for some reason your altimeter may be 75 feet too low, and then you have an updraft which may temporarily put you in Bravo would you recommend asking control to show what your altitude is when you are at 1800 feet to confirm your altimeter is giving the correct reading?

Another question, if you hear you are number 2 for a runway following xyz make of plane, and you see the plane land do you confirm that you are cleared to land? I like doing so, but don't want to be a pain when controllers are busy. I just think its safer.

Thanks

 

[roncachamp]

On Sunday flying back into the Chicago area, I was worried about the ORD Bravo. There is an area where Bravo starts at 1900 feet, so because it was bumpy I tried to stay at 1700 feet, but that is a little low for my liking if I am not in a pattern. If you trim for 1800 feet, and for some reason your altimeter may be 75 feet too low, and then you have an updraft which may temporarily put you in Bravo would you recommend asking control to show what your altitude is when you are at 1800 feet to confirm your altimeter is giving the correct reading?

The controller should verify the Mode C display when radar contact is established. If the displayed altitude is not more than 200 feet off the altitude you report it's within limits for ATC use.

Another question, if you hear you are number 2 for a runway following xyz make of plane, and you see the plane land do you confirm that you are cleared to land? I like doing so, but don't want to be a pain when controllers are busy. I just think its safer.

You must receive a landing clearance before the wheels touch the surface.

 

[mcmanigle]

You must receive a landing clearance before the wheels touch the surface.

There is a difference between "you are number two for runway XX" and "cleared to land runway XX, number two behind a YY." If the words "cleared to land" happen, you don't need to ask again. There's no harm in double checking though, especially if for whatever reason you can't visually verify that the YY in front of you landed and taxied off the runway.

 

[livitup]

The controller should verify the Mode C display when radar contact is established. If the displayed altitude is not more than 200 feet off the altitude you report it's within limits for ATC use.

Does that mean that you won't be tagged for a deviation if you bust by less than 200 feet?

Scenario: Bravo starts at 2000. Joe Pilot's altimeter reads 1900. Mode C is reporting 1950. Joe says "Chicago Center, Bugsmasher 123, Level 1900." Controller sees 1950, but says nothing about it because it's "within limits" and replies "roger". Joe then climbs to 1950 on his altimeter, Mode C is now reporting 2000. Then a sudden updraft pushes him up 20 feet to 1970/2020. Has he violated the Bravo?

Sorry if this is a pedantic question, and yes, I realize Joe is making decisions that cut it really close, putting himself in this potentially dangerous situation. But lets assume he had a good reason for wanting to be at that altitude.

Background, I'm a 25 hour student who hasn't quite started XC work yet. I fly in E airspace, but I'm about 15 miles from the SFRA and IAD B, so I'm interested in how this stuff works. Sorry if it's a dumb question.

 

[poadeleted20]

If you trim for 1800 feet,

You trim for speed, not altitude. You deal with up/down-drafts with manual pitch inputs, not trim. In such a situation, it's up to you to actively fly the plane so it stays on altitude.

and for some reason your altimeter may be 75 feet too low, and then you have an updraft which may temporarily put you in Bravo would you recommend asking control to show what your altitude is when you are at 1800 feet to confirm your altimeter is giving the correct reading?

If the up/down-drafts are so strong you can't maintain desired altitude within 100 feet, then choose a lower altitude so your deviations stay below the floor of the Bravo.

Another question, if you hear you are number 2 for a runway following xyz make of plane, and you see the plane land do you confirm that you are cleared to land?

That depends on what the controller has already told you. If you were told "Cleared to land, number two behind a Cessna on short final," then no, you are not required to confirm your clearance to land. If you were told "Continue, number two behind a Cessna on one mile final," the you do have to hear the words "cleared to land" before you do land, and if you don't hear them by short final, you must obtain that clearance or go around.

That said, if for any reason you are uncertain about whether or not you're cleared to land, ask again. And if the controller gets short tempered about that, shrug it off as the controller having had a bad day because you did the right thing.

I like doing so, but don't want to be a pain when controllers are busy.

You'll be a lot bigger pain in their lives if you land without clearance.

I just think its safer.

...and you're right. If you're going to make a small mistake, make it on the side of safety.

 

[poadeleted20]

Does that mean that you won't be tagged for a deviation if you bust by less than 200 feet?

I'll let the controllers answer that one.

Joe Pilot's altimeter reads 1900. Mode C is reporting 1950.

ATC only sees altitude in 100-foot increments. They'll see either 1900 or 2000 (019 or 020 on their display), not "1950".

Joe says "Chicago Center, Bugsmasher 123, Level 1900." Controller sees 1950, but says nothing about it because it's "within limits" and replies "roger". Joe then climbs to 1950 on his altimeter, Mode C is now reporting 2000. Then a sudden updraft pushes him up 20 feet to 1970/2020. Has he violated the Bravo?

If you actually reach 2020 MSL, then technically you have violated the B-space. However (and again, subject to controller confirmation) it is doubtful anyone will get excited if they briefly see 020 on their scope before it goes back to 019.

Sorry if it's a dumb question.

No dumb questions (other than those not asked out of fear), only dumb answers.

 

[Marauder]

Since we are talking altitude deviations, where does FlightAware get the altitudes reported on their site? I see my IFR flight altitudes usually 200' higher in FlightAware than the altitude I am flying. My obvious concern is if I get a little sloppy on altitude and climb 100', will this get me caught by the snitch?

 

[FWTxPilot]

On Sunday flying back into the Chicago area, I was worried about the ORD Bravo. There is an area where Bravo starts at 1900 feet, so because it was bumpy I tried to stay at 1700 feet, but that is a little low for my liking if I am not in a pattern. If you trim for 1800 feet, and for some reason your altimeter may be 75 feet too low, and then you have an updraft which may temporarily put you in Bravo would you recommend asking control to show what your altitude is when you are at 1800 feet to confirm your altimeter is giving the correct reading?

Thanks

I asked almost this exact same question when I was training because I was not sure how accurately the controllers could pinpoint altitude. If the class B shelf starts at 2000 and I am at 1900 per my altimeter, is it a bust if the controller shows me at 2000. I am assuming you are staying out of the Bravo because you are a solo student?

My instructor basically told me that if the controller feels it was a violation, then it is and you can be held accountable. His advice was to stay well below the shelf if safety permits, or fly around the B under a shelf that allows you to be at a higher altitude.

 

[rbridges]

I asked almost this exact same question when I was training because I was not sure how accurately the controllers could pinpoint altitude. If the class B shelf starts at 2000 and I am at 1900 per my altimeter, is it a bust if the controller shows me at 2000. I am assuming you are staying out of the Bravo because you are a solo student?

My instructor basically told me that if the controller feels it was a violation, then it is and you can be held accountable. His advice was to stay well below the shelf if safety permits, or fly around the B under a shelf that allows you to be at a higher altitude.

I'm a little rusty, but isn't tolerance 75ft at ground level for an altimeter to be legal for Ifr? I would always error on the side of safety but I can't see atc giving more than a verbal warning if they see a slight ceiling bust into bravo. Keep doing it and I could see it getting ugly.

I would personally give myself buffer and get radar services.

 

[poadeleted20]

There are times and places where the legal window is too small for much if any buffer. For example, when working under the 1500 MSL shelf of the B-space around BWI Airport in Maryland, the ground below is most definitely "congested" by the FAA's definition, requiring 1000 above the highest obstruction. With surface elevation of around 140 MSL and uncharted things sticking up 200 feet above that, your minimum legal altitude is just below 1400 MSL. Not much of a window there, so most folks run right at 1400 indicated and I've never heard Potomac griping about someone briefly reading 015 on their scope.

Further, IIRC, ATC is required to keep the jets at least 500 above the floor of the B-space, so indicating at 1500 MSL still keeps their required vertical separation from VFR traffic, and they're not going to get much excited about that.

 

[flyingron]

Further, IIRC, ATC is required to keep the jets at least 500 above the floor of the B-space, so indicating at 1500 MSL still keeps their required vertical separation from VFR traffic, and they're not going to get much excited about that.

Jets perhaps, but ATC is more than happy to put me as a piston plane right on the floor of the class B and less than 200' above the traffic pattern at JYO they were having me hold over (I suggested I could hold somewhere else or HIGHER but buzzing back and forth within a few hundred feet of the traffic there was getting on my nerves.

 

[asgcpa]

That depends on what the controller has already told you. If you were told "Cleared to land, number two behind a Cessna on short final," then no, you are not required to confirm your clearance to land. If you were told "Continue, number two behind a Cessna on one mile final," the you do have to hear the words "cleared to land" before you do land, and if you don't hear them by short final, you must obtain that clearance or go around.

That said, if for any reason you are uncertain about whether or not you're cleared to land, ask again. And if the controller gets short tempered about that, shrug it off as the controller having had a bad day because you did the right thing.

You'll be a lot bigger pain in their lives if you land without clearance.

...and you're right. If you're going to make a small mistake, make it on the side of safety.

I thought he said cleared to land #2 behind a Hawker, but, wasn't sure. It was quite a busy day. Also, usually they warn yo about wake turbulence landing behind a bigger jet if you are in a small plane. Didn't hear that either.

Thanks for the input.

 

[asgcpa]

I am assuming you are staying out of the Bravo because you are a solo student?

No, I have my private certificate. But, ORD controllers tell everyone who are not on an IFR flight plan to stay clear of ORD Bravo. They are not as accomodating as the St. Louis controllers.

 

[FWTxPilot]

No, I have my private certificate. But, ORD controllers tell everyone who are not on an IFR flight plan to stay clear of ORD Bravo. They are not as accomodating as the St. Louis controllers.

That's what I get for assuming... I can't really relate, fortunately in the few experiences I have had in the class B around DFW I have always been given clearance, even when I was right at the bottom of the shelf.

When I ask for flight following the local tower will tell me to remain clear, but when I get with approach I just request B transition and they usually grant it depending on my destination. ORD is much busier, so I could see where this might not be worth the trouble.

Sorry, I realize this post was intended for controllers, just thought I would share.

 

[poadeleted20]

I thought he said cleared to land #2 behind a Hawker, but, wasn't sure.

His exact words in the post were "you hear you are number 2 for a runway following xyz make of plane." Nothing there about "cleared" or "continue", but either way, if you don't hear "cleared to land", then you definitely need to ask further before crossing the threshold.

 

[Approach_controller]

ATC can and will use all of the Bravo to sequence arrivals. There is no artificial floor of must remain 500 feet above the Bravo or what have you. If the floor of the Bravo is say, 2,000 a jet could very well be there at 2,000. The only thing we are asked to do is to keep arrivals to the main airport contained within the Bravo to the extent possible. If you're at 1,999 you're legal. I'd be vigilant if I were cutting it that close as there is no guarantee ATC sees you there.

I've never seen a violation called on a pilot who has a mode C that just bumps the Bravo. As has been mentioned, even if some knucklehead controller tried to bust you for 100 or 200 feet, hey my mode C must have been a little off. The ones getting violated 99% of the time are the ones who brazenly bore on through the Bravo causing all sorts of chaos.

They didn't give a wake turbulence advisory to you because in our rule book a hawker is a small weight class as were you so it wasn't required.

 

[MAKG1]

You also need to ask if there is the slightest doubt.

Occasionally on a really busy day when I was cleared #4 for landing on 31 behind a Cirrus on the opposite downwind, I'll ask Tower to confirm landing clearance from final, which they immediately oblige.

 

[Jeff Oslick]

If you're at 1,999 you're legal. I'd be vigilant if I were cutting it that close as there is no guarantee ATC sees you there.

A big concern I have when crossing beneath the LAX Class B floors are wake turbulence from the conga-line above me. I always try to fly across (under) perpendicular to the direction of flight of the jets, to minimize my wake turbulence exposure time, and to visualize the likely points of wake turbulence (based on an average 400 fpm sink rate of the vortex; not sure where I picked up that rule of thumb) to avoid them.

 

[BillTIZ]

No, I have my private certificate. But, ORD controllers tell everyone who are not on an IFR flight plan to stay clear of ORD Bravo. They are not as accomodating as the St. Louis controllers.

Sounds like they were either trained at, or are in training for, LAS.
"Unable, Remain Clear of Class B"

 

[roncachamp]

Does that mean that you won't be tagged for a deviation if you bust by less than 200 feet?

Scenario: Bravo starts at 2000. Joe Pilot's altimeter reads 1900. Mode C is reporting 1950. Joe says "Chicago Center, Bugsmasher 123, Level 1900." Controller sees 1950, but says nothing about it because it's "within limits" and replies "roger".

Mode C is displayed in 100 foot increments using two digits, a display of "19" is 1900 MSL.

Joe then climbs to 1950 on his altimeter, Mode C is now reporting 2000. Then a sudden updraft pushes him up 20 feet to 1970/2020. Has he violated the Bravo?

No, he's 30 feet below Class B airspace at 1970 MSL. And he's talking with the wrong ATC facility.

 

[poadeleted20]

Mode C is displayed in 100 foot increments using two digits, a display of "19" is 1900 MSL.

Only two digits? Then how does 28,000 show up as opposed to 2800?

Actually, it's 2-3 digits, showing the altitude in hundreds, so 2800 is 28, but 28,000 is 280. Leading zeros are, contrary to what I said above, dropped.

 

[livitup]

Thanks Steve and Ron, I think I once knew that altitude shows rounded to the nearest 100 on the scopes, but I forgot it when that scenario popped into my head... And Steve, I guess he'd be talking to Chicago Approach?

What I get from this is that if you're communicating, and sensible, and react to instructions, a ***minor*** bust like that would ***probably*** not be a big deal.

Still better to plan to prevent it, by giving one's self plenty of cushion. But it's also good to know the reality of the situation if something were to force you up that close to the floor of airspace.

 

[roncachamp]

Only two digits? Then how does 28,000 show up as opposed to 2800?

He was at 1900 MSL.

 

[stratobee]

Just the other night I got carried away under LAX B shelf on the approach. I was out showing my friend the sights at night, and there were these low clouds. One particular one was a little higher. It was right in our path on the way back to El Monte from the Mini Route, so I started climbing over it. Just as I was about to clear it, I realised the shelf starts at 2500ft there and I was at 3000ft!. Right under the approach path to 25L it was, too! I was kicking myself, because I should know better - I fly that particular corridor every week. Such a stupid schoolboy mistake. I called up the controller HHR and fessed up. Asked if he could check with SoCal, fully expecting to get my a** handed to me on a platter with a number they want me to call. After he checked, he just came back with a "you're good, no bust recorded". So either my mode C was different enough from the actual, or there is some padding built in.

Close call.

 

[Tony_Scarpelli]

whenever I have been cleared to land behind a jet they always ask if I saw the jet land so I know where to position my landing as not to come into contact with WTV.

I thought he said cleared to land #2 behind a Hawker, but, wasn't sure. It was quite a busy day. Also, usually they warn yo about wake turbulence landing behind a bigger jet if you are in a small plane. Didn't hear that either.

Thanks for the input.

 

[roncachamp]

Thanks Steve and Ron, I think I once knew that altitude shows rounded to the nearest 100 on the scopes, but I forgot it when that scenario popped into my head... And Steve, I guess he'd be talking to Chicago Approach?

Affirmative.

 

[Approach_controller]

Just the other night I got carried away under LAX B shelf on the approach. I was out showing my friend the sights at night, and there were these low clouds. One particular one was a little higher. It was right in our path on the way back to El Monte from the Mini Route, so I started climbing over it. Just as I was about to clear it, I realised the shelf starts at 2500ft there and I was at 3000ft!. Right under the approach path to 25L it was, too! I was kicking myself, because I should know better - I fly that particular corridor every week. Such a stupid schoolboy mistake. I called up the controller HHR and fessed up. Asked if he could check with SoCal, fully expecting to get my a** handed to me on a platter with a number they want me to call. After he checked, he just came back with a "you're good, no bust recorded". So either my mode C was different enough from the actual, or there is some padding built in.

Close call.

No harm no foul :wink2:

They probably noticed, but it wasn't impacting a thing and you were clearly aware and fessed up. Every controller has made mistakes themselves. I've vectored for the wrong approach (VMC, VFR jet wanting opposite direction practice approach at a dead airport, busy vectoring final to 7 other airports). The pilot went so far as to fly the approach and nicely asked if the next one could be the one he REALLY wanted. Beat myself up for that one for a looooong time.

 

[BillTIZ]

Just the other night I got carried away under LAX B shelf on the approach. I was out showing my friend the sights at night, and there were these low clouds. One particular one was a little higher. It was right in our path on the way back to El Monte from the Mini Route, so I started climbing over it. Just as I was about to clear it, I realised the shelf starts at 2500ft there and I was at 3000ft!. Right under the approach path to 25L it was, too! I was kicking myself, because I should know better - I fly that particular corridor every week. Such a stupid schoolboy mistake. I called up the controller HHR and fessed up. Asked if he could check with SoCal, fully expecting to get my a** handed to me on a platter with a number they want me to call. After he checked, he just came back with a "you're good, no bust recorded". So either my mode C was different enough from the actual, or there is some padding built in.

Close call.

I'd file a NASA form anyway.

 

[BillTIZ]

Further, IIRC, ATC is required to keep the jets at least 500 above the floor of the B-space, so indicating at 1500 MSL still keeps their required vertical separation from VFR traffic, and they're not going to get much excited about that.

Does not work that way around here, airliners and others on approach were always busting the floor of Class B on descent before they would get to a lower ring.

They just expanded the Class B in an attempt to contain them. But it's not looking good so far. They also released and RNAV Visual to "signatory" participants and they are always busting the Class B floor.