Is the 200 knot speed limit a lie?

kicktireslightfires

kicktireslightfires

Pre-takeoff checklist
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kicktireslightfires
Or is ADS-B data inaccurate? Because I see the jets flying 270 and 280 knots all the time under 10k feet or even under 5k feet and I don't understand it if the speed limit is 250 knots under 10k MSL and max of 200 knots under 10k MSL while in Class B airspace. Both of these screenshots below are from within class B airspace so per my understanding of the rules, they should be flying no faster than 200 knots. I've noticed this for a while and probably 80% of the jets I see under 10k MSL are doing well in excess of those speed limits so I'm unsure if the ADS-B data is wrong or if just no one actually follows these speed limits and ATC doesn't care.

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Makes sense. But wouldn't that mean if their ground speed is 280kts and their max allowed is 200kts that they would be getting tailwinds of 80 knots... at a few thousand feet??

If so, that makes no sense. The screenshots I posted above were taken minutes apart. One plane is going south and the other is going north. Were the winds going 80 knots one direction and then switched 80 knots the other direction 60 seconds later? :p
 
"Unless otherwise authorized"

and

"(d) If the minimum safe airspeed for any particular operation is greater than the maximum speed prescribed in this section, the aircraft may be operated at that minimum speed."
 
kicktireslightfires said:
Makes sense. But wouldn't that mean if their ground speed is 280kts and their max allowed is 200kts that they would be getting tailwinds of 80 knots... at a few thousand feet??

If so, that makes no sense. The screenshots I posted above were taken minutes apart. One plane is going south and the other is going north. Were the winds going 80 knots one direction and then switched 80 knots the other direction 60 seconds later? :p
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Us jets don’t generally fly in the 200 zone except on final.... it’s 250 under 10k that’s the big one.


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kicktireslightfires said:
Or is ADS-B data inaccurate? Because I see the jets flying 270 and 280 knots all the time under 10k feet or even under 5k feet and I don't understand it if the speed limit is 250 knots under 10k MSL and max of 200 knots under 10k MSL while in Class B airspace. Both of these screenshots below are from within class B airspace so per my understanding of the rules, they should be flying no faster than 200 knots.
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There's no speed limit specific to Class B airspace. Most, but not all, Class B is below 10,000, so the 250 limit usually applies.
 
The speed limit *IN* Class B is never less than 250 KIAS. (Above 10,000' MSL there is no speed limit, even when in Class B)

The speed limit *UNDER* Class B is 200 KIAS. Airliners operating to or from the primary airport will rarely be below Class B.

KIAS must be converted to KTAS. 250 KIAS at 8,000' - 10,000' is ~280 - ~290 KTAS, depending on temperature and pressure.
 
kicktireslightfires said:
Or is ADS-B data inaccurate? Because I see the jets flying 270 and 280 knots all the time under 10k feet or even under 5k feet and I don't understand it if the speed limit is 250 knots under 10k MSL and max of 200 knots under 10k MSL while in Class B airspace. Both of these screenshots below are from within class B airspace so per my understanding of the rules, they should be flying no faster than 200 knots. I've noticed this for a while and probably 80% of the jets I see under 10k MSL are doing well in excess of those speed limits so I'm unsure if the ADS-B data is wrong or if just no one actually follows these speed limits and ATC doesn't care.

Image.jpg
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You nailed 'em, Barney. Take the bullet out of your pocket and go get 'em.
 
Larry in TN said:
The speed limit *UNDER* Class B is 200 KIAS. Airliners operating to or from the primary airport will rarely be below Class B.
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Just to provide the regulatory reference from 91.131:
(2) Unless otherwise authorized by ATC, each person operating a large turbine engine-powered airplane to or from a primary airport for which a Class B airspace area is designated must operate at or above the designated floors of the Class B airspace area while within the lateral limits of that area.
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So when you hear verbiage like "Delta 1234 XxxCenter speed restriction....". Is that where ATC is authorizing them to either exceed or go back to adhering to the limit.
 
Sinistar said:
So when you hear verbiage like "Delta 1234 XxxCenter speed restriction....". Is that where ATC is authorizing them to either exceed or go back to adhering to the limit.
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ATC can’t authorize exceeding regulatory speed limits, But they can authorize exceeding published speeds on SIDs and STARs, or restrict speeds to something less than the regulatory or published speeds.
 
MauleSkinner said:
ATC can’t authorize exceeding regulatory speed limits, But they can authorize exceeding published speeds on SIDs and STARs, or restrict speeds to something less than the regulatory or published speeds.
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Except 91.117 also includes:

(d) If the minimum safe airspeed for any particular operation is greater than the maximum speed prescribed in this section, the aircraft may be operated at that minimum speed.
 
Doc Holliday said:
Except 91.117 also includes:

(d) If the minimum safe airspeed for any particular operation is greater than the maximum speed prescribed in this section, the aircraft may be operated at that minimum speed.
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Arent there some planes like older Russian commercial planes that need to operate above these minimums?
 
Sinistar said:
So when you hear verbiage like "Delta 1234 XxxCenter speed restriction....". Is that where ATC is authorizing them to either exceed or go back to adhering to the limit.
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No.

Look at the regulation for each speed restriction. If it says, "Unless authorized or required by ATC", then ATC can waive it. If it says, "Unless authorized by the Administrator", then ATC can not. The 250 KIAS below 10,000' is the later.

The speed reduction at 10,000' is the default in the FMS. 240 KIAS on Boeings, 250 KIAS on Airbus, though many flying Boeings will change it to 250. I've never seen anyone intentionally fly above 250 KIAS below 10,000' (other than when outside 12nm from shore or during the high-speed departure test in IAH back in the 1990s).

Sinistar said:
Arent there some planes like older Russian commercial planes that need to operate above these minimums?
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Military fighters and large, heavy transports. B767, B747, A340/380, MD11, etc.
 
Bill Jennings said:
Man, where are those 50kt tailwinds when I need them?
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If you find those tailwinds please share with the group. Anytime I want to know what direction the wind is coming from I look out the windscreen.

BTW, breaking the 200 knot limit is something I'm certain I will never have to worry about ...
 
Sinistar said:
So when you hear verbiage like "Delta 1234 XxxCenter speed restriction....". Is that where ATC is authorizing them to either exceed or go back to adhering to the limit.
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AIM 5-5-9

Items of note is a. 2 (a) and (b). They assign it, you comply, except with an assignment faster than 250 above 10,000, you must be at 250 before going below 10,000.

Controllers are not supposed to assign speeds that do not comply FAR’s. That does not change FAR 91.123 (b). They assign, you comply. Yeah, you should question
 
Many years ago descending below 10 into the DFW metroplex.....

ATC:“ aircraft 123 say airspeed?”

123: “250”

ATC: “Southwest 567, say airspeed?”

SW567: “250”

ATC: “OK Southwest 567, I’ll need you to adjust your speed, you’re in trail and overtaking aircraft 123 by 60 knots”......
 
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It’s more of just a small fib. ;)
 
unsafervguy said:
But there is 250 and then there is southwest 250...........
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There really isn't. At an airport of any size, arrivals/departures are lined up with everyone doing the same speeds. If someone isn't flying the appropriate speed they'll gain ground on the aircraft ahead of them and separation will be lost.

There's also the FOQA programs that download the data from the FDRs for safety threat analysis. If flights are routinely exceeding speed limits, FOQA will find it and the company, union, and FAA will know about it.

https://en.wikipedia.org/wiki/Flight_operations_quality_assurance
 
Larry in TN said:
There really isn't. At an airport of any size, arrivals/departures are lined up with everyone doing the same speeds. If someone isn't flying the appropriate speed they'll gain ground on the aircraft ahead of them and separation will be lost.

There's also the FOQA programs that download the data from the FDRs for safety threat analysis. If flights are routinely exceeding speed limits, FOQA will find it and the company, union, and FAA will know about it.

https://en.wikipedia.org/wiki/Flight_operations_quality_assurance
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My post was something that happened many years ago (late 80's, early 90's). Yes, back then SW was rather known for their rather fast "250 below 10" procedure, hence the controllers snarky remarks about adjusting speed.
 
250 knots indicated is about 289 knots true on a hot day at 7500 feet. So your baseline is 289 and then you have to factor in winds. There is no 200 knot rule in class B airspace.
 
Doc Holliday said:
My post was something that happened many years ago (late 80's, early 90's). Yes, back then SW was rather known for their rather fast "250 below 10" procedure, hence the controllers snarky remarks about adjusting speed.
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Amateurs. PSA was the masters of that
 
One thing that a lot of people forget is the 200 knot speed limit below the class B. Its also enforced differently at different metros. Slow to 200 below the NY class B and ATC will yell at you for doing it. Forget to do it below ATL's class B, and they will yell at you for not doing it.
 
Groundpounder said:
One thing that a lot of people forget is the 200 knot speed limit below the class B. Its also enforced differently at different metros. Slow to 200 below the NY class B and ATC will yell at you for doing it. Forget to do it below ATL's class B, and they will yell at you for not doing it.
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Yell right back at them. ATC does not have the authority to authorize you to exceed 200 KIAS below Class B Airspace.

I've had that problem at DEN. On an assigned speed of 210 KIAS they'll descent us below the floor of Class B (without even telling us). Before Jepp FD Pro with own-ship display, you probably wouldn't catch it. I've filled out a few ASAP reports over that. I really do have better things to do at that point than keeping a close eye on what ATC is doing.
 
Larry in TN said:
Yell right back at them. ATC does not have the authority to authorize you to exceed 200 KIAS below Class B Airspace.

I've had that problem at DEN. On an assigned speed of 210 KIAS they'll descent us below the floor of Class B (without even telling us). Before Jepp FD Pro with own-ship display, you probably wouldn't catch it. I've filled out a few ASAP reports over that. I really do have better things to do at that point than keeping a close eye on what ATC is doing.
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I don't disagree with you, but sometimes you have to be flexible with them....NY is a special place.....doesn't make it right, but that is the reality.
 
Larry in TN said:
There really isn't. At an airport of any size, arrivals/departures are lined up with everyone doing the same speeds. If someone isn't flying the appropriate speed they'll gain ground on the aircraft ahead of them and separation will be lost.

There's also the FOQA programs that download the data from the FDRs for safety threat analysis. If flights are routinely exceeding speed limits, FOQA will find it and the company, union, and FAA will know about it.

https://en.wikipedia.org/wiki/Flight_operations_quality_assurance
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sorry you didn't get that that was an airline pilot joke.

just like did you hear about the woman that only dated airline pilots, she was dating a delta pilot but that relationship was to turbulent. now she is dating a southwest pilot but he is to direct..........
 
Groundpounder said:
I don't disagree with you, but sometimes you have to be flexible with them....NY is a special place.....doesn't make it right, but that is the reality.
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It certainly isn't right. I was based in EWR/LGA for almost three years and still fly into both airports with some regularity. The NY controllers have their distinctive personality but I never had any trouble with them. Never had NY approach try to take me under the Class B airspace going into either EWR or LGA.

Worst I saw (heard?) was going into PHL one night. Speedbird asked Philly approach for the QNH. The controller didn't understand what she was asking for. When he finally figure it out he gave her a short lecture on how it was called the "altimeter setting".

unsafervguy said:
sorry you didn't get that that was an airline pilot joke.
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I got it. I've heard it for years. Keep repeating it, though, and people will believe it is the norm.
 
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