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for the FAR lawyers - Airspeed limits

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for the FAR lawyers - Airspeed limits

Old 20th Mar 2024, 14:39
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for the FAR lawyers - Airspeed limits

ok FAR experts

https://www.ecfr.gov/current/title-1...section-91.117

Departing IFR out of LAX. Climbing thru 5000. Crossing 5000 feet, Departure says "Maintain 280 (knots) or better, climb and maintain 17,000"

Since this is an "ATC directive", you are approved to fly 280 below 10,000, or do you wait until 10,000 before selecting 280?

I say do it when ATC says to do it, since he may be seeing soon-to-merge electronic dots on his radar scope

Thanks



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Old 20th Mar 2024, 15:02
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Then why in reference to speed limits on or around Class B, C, and D does does it allow for “required by ATC”? The traditional answer is ATC cannot override the the 250 below 10,000’ rule.
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Old 20th Mar 2024, 22:02
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Originally Posted by 321XLR
ok FAR experts

https://www.ecfr.gov/current/title-1...section-91.117

Departing IFR out of LAX. Climbing thru 5000. Crossing 5000 feet, Departure says "Maintain 280 (knots) or better, climb and maintain 17,000"

Since this is an "ATC directive", you are approved to fly 280 below 10,000, or do you wait until 10,000 before selecting 280?

I say do it when ATC says to do it, since he may be seeing soon-to-merge electronic dots on his radar scope

Thanks
  • What aircraft
  • What was your rate of climb
  • Which SID if any?
  • How far offshore ?

If you’re flying a big jet and your rate of climb at the time of transmission was 3000+ then it’s only a minute and a half to 10,000.

Except as provided in paragraphs (b), (c), (e), and (f) of this section and §§ 91.701 and 91.703, this part prescribes rules governing the operation of aircraft within the United States, including the waters within 3 nautical miles of the U.S. coast.

(b) Each person operating an aircraft in the airspace overlying the waters between 3 and 12 nautical miles from the coast of the United States must comply with §§ 91.1 through 91.21; §§ 91.101 through 91.143; §§ 91.151 through 91.159; §§ 91.167 through 91.193; § 91.203; § 91.205; §§ 91.209 through 91.217; § 91.221, § 91.225; §§ 91.303 through 91.319; §§ 91.323 through 91.327; § 91.605; § 91.609; §§ 91.703 through 91.715; and § 91.903.
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Old 20th Mar 2024, 22:21
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I claim no expertise with the FARs but have had involvement with the equivalents in other states. Reading the regs that you link to, it seems very clear to me that ATC is inviting you to get a slap on the wrist (or worse) if you exceed 250kts before passing 10,000ft. Para (b) of the regs is an example of the structure used when an exception can be authorised/instructed by ATC.
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Old 20th Mar 2024, 22:33
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In short LAX is on the shoreline or as good as.
Departing to anywhere between SW and NW at 180-240kts will get you at 12 miles in 3-4 minutes after which the 250<10K no longer applies.
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Old 21st Mar 2024, 00:46
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My understanding for the US, based on the types of regulations that are in force, is that ATC has the authority to allow you to exceed certain speed limits(such as a maximum of 200 knots when within a certain distance of certain airports below a certain altitude) but does not have the legal authority to waive the 250K below 10,000'. Only the administrator can authorize an aircraft to exceed 250 knots(this could be as a publication such as a temporary high speed climb authorization on a SID out of Houston a few years back). One should note that we used to regularly request from ATC a speed of 280 knots below ten thousand feet and ATC would approve it. That doesn't mean that it was legal.
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Old 21st Mar 2024, 17:22
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Having departed LAX to the west with an easterly destination many times I would say it is almost entirely normal to be given this exact instruction.

Initial call to Socally results in “Maintain 280 knots” then when leaving 10000’ asked to “resume normal speed”.

Its the only place in the country where I see this routinely occur.

I have spoken to an ATCer several years ago who worked under the impression there is a waiver for speed below 10k off the coast to accommodate heavies with a westerly departure to permit flap retraction to clean speed.

The instructions certainly sound to me to imply an authorization to 280 knots below 10k.
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Old 21st Mar 2024, 17:34
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Originally Posted by oicur12.again
I have spoken to an ATCer several years ago who worked under the impression there is a waiver for speed below 10k off the coast to accommodate heavies with a westerly departure to permit flap retraction to clean speed.
This applies everywhere the FAR applies.
Heavies can accelerate to their min clean speed if above 250kts.
No request or clearance required although I do always notify ATC of my speed requirements below 10K.

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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Old 22nd Mar 2024, 10:04
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Originally Posted by B2N2
This applies everywhere the FAR applies.
Heavies can accelerate to their min clean speed if above 250kts.
No request or clearance required although I do always notify ATC of my speed requirements below 10K.
That’s what I do as I have a similar understanding, although I have yet to find an actual reference allowing the practice as theoretically you could keep some flap out and clean up at 10,000’ to follow the letter of the law.
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Old 22nd Mar 2024, 14:14
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Hope this helps, FAA legal take on this

Essentially if you configure the aircraft to meet a speed requirement than do so.

it mentions minimum safe speed, not minimum clean speed. Someone asked if the could fly a 737 clean, and they turned around and said no, configure the jet.

they also talk about ATC requirements

https://www.faa.gov/about/office_org/headquarters_offices/agc/practice_areas/regulations/interpretations/data/interps/2010/Seltzer-Continental%20Airlines_2010_Legal_Interpretation.pdf

Last edited by swh; 22nd Mar 2024 at 14:38.
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Old 22nd Mar 2024, 23:03
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Get this frequently out of LAX. The intent is at 10,000 that you’ll accelerate to 280 kts. The “administrator” can authorize speeds in excess 250 kts below 10,000 (IAH a number of years ago) individual controllers however cannot invoke the administrator’s authority.

Now if you need in excess of 250, that’s a different story.
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Old 23rd Mar 2024, 00:32
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Originally Posted by swh
Hope this helps, FAA legal take on this

Essentially if you configure the aircraft to meet a speed requirement than do so.

it mentions minimum safe speed, not minimum clean speed. Someone asked if the could fly a 737 clean, and they turned around and said no, configure the jet.

they also talk about ATC requirements

https://www.faa.gov/about/office_org...rpretation.pdf
No it doesn’t.
That interpretation specifies landing aircraft.
The whole truth:

Get this frequently out of LAX. The intent is at 10,000 that you’ll accelerate to 280 kts. The “administrator” can authorize speeds in excess 250 kts below 10,000 (IAH a number of years ago) individual controllers however cannot invoke the administrator’s authority.

Now if you need in excess of 250, that’s a different story.
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Old 24th Mar 2024, 03:06
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Thank you to the contributors here - this has been a very helpful discussion, directly relating to the same experience with the same direction by SOCAL for our aircraft heading west.
Where the confusion lies (for international operators like us) is that there are MANY non-US FIRs around the world where there is NO speed restriction for IFR aircraft operating in Class C airspace below 10,000'.
So the ATC instruction, "cancel speed restrictions" is common and permits speeds greater than 250 KIAS below 10,000'. In Australia, we are routinely permitted (with ATC explicit instruction) to exceed 250 KIAS below 10,000'.
The reason ATC still has to "cancel the speed restrictions below 10K" is that the SID/Departure or STAR/Arrival Chart will specify "maximum speed below 10,000' is 250 KIAS".
On the most recent departure from LAX heading west, we were given the same instruction to ""Maintain 280 (knots) or better, climb and maintain XX,000"
We, evidently incorrectly, immediately accelerated to 280 KIAS - instead of waiting to reach 10,000'.
This flagged on our FOQA and a robust discussion was had.
Anyway, we had already determined that the best course (in US airspace) was to delay the acceleration until 10,000' - which we'll do next time.

Last edited by josephfeatherweight; 24th Mar 2024 at 21:34. Reason: Added "SID/Departure" for clarity.
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Old 24th Mar 2024, 17:27
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We, evidently incorrectly, immediately accelerated to 280 KIAS - instead of waiting to reach 10,000'.
I’d have done the same as you.
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Old 2nd Apr 2024, 04:33
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Originally Posted by josephfeatherweight
Thank you to the contributors here - this has been a very helpful discussion, directly relating to the same experience with the same direction by SOCAL for our aircraft heading west.
Where the confusion lies (for international operators like us) is that there are MANY non-US FIRs around the world where there is NO speed restriction for IFR aircraft operating in Class C airspace below 10,000'.
So the ATC instruction, "cancel speed restrictions" is common and permits speeds greater than 250 KIAS below 10,000'. In Australia, we are routinely permitted (with ATC explicit instruction) to exceed 250 KIAS below 10,000'.
The reason ATC still has to "cancel the speed restrictions below 10K" is that the SID/Departure or STAR/Arrival Chart will specify "maximum speed below 10,000' is 250 KIAS".
On the most recent departure from LAX heading west, we were given the same instruction to ""Maintain 280 (knots) or better, climb and maintain XX,000"
We, evidently incorrectly, immediately accelerated to 280 KIAS - instead of waiting to reach 10,000'.
This flagged on our FOQA and a robust discussion was had.
Anyway, we had already determined that the best course (in US airspace) was to delay the acceleration until 10,000' - which we'll do next time.
If you’re an international operator, you will be operating under a FAA Part 129 certificate. As part of the approval, you will have a FAA approved OpsSpec, which for most international carriers it contains the approval from the administrator to exceed 250 below 10,000. You will also be outside 12 nm fairly smartly as well departed westbound from LAX.
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Old 2nd Apr 2024, 05:24
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Depart LAX about once a week, and have for the last decade. First call from departure 99%:"climb to 17k', when able maintain 280". Definitely should be:"passing 10k' accelerate to 280".
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Old 2nd Apr 2024, 08:48
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Or you may have a Part 375 (for commercial ops) approval and no such OpsSpec.
Or you may be operating privately.
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