Hi Tech Ops Forum,

I completed a search, but didn't find a good answer on airliners.net.

I am very used to North America and Europe where there's generally a limit under 10,000 feet of 250 KIAS (indicated air speed) or something similar (of course there are always exceptions). There have been some exceptions, but I haven't flown too much faster when we're in crowded airspace, Class B, etc.

However, after flying into and out of Singapore, I noticed, especially upon departure back to the US on United, that we far exceeded 250 KIAS on departure and climbed out at a higher speed than I'm used to (albeit shallower as well).

For example, I flew from SFO to IAH on UAL1677 and was at 282 knots ground speed at 10,000 feet
[url]https://flightaware.com/live/flight/UAL1677/history/20221120/1916Z/KSFO/KIAH/tracklog
[/url]

Similarly, when I flew IAH to SFO on UAL2621, we were at 289 knots ground speed at 10,700 feet
https://flightaware.com/live/flight/UAL2621/history/20221111/0142Z/KIAH/KSFO/tracklog

However, on UAL2 from SIN to SFO, we were already at 399 knots (459 MPH) ground speed at 10,200 feet. That's the fastest I believe that I've ever flown at that altitude when taking off.
https://flightaware.com/live/flight/UAL2/history/20221120/0225Z/WSSS/KSFO/tracklog

I confirmed that this isn't a one-off and other flights have a similar pattern. Those that head north into Malaysia appear to fly a bit slower though:
https://flightaware.com/live/flight/SIA122/history/20221117/0850Z/WSSS/WMKK/tracklog

It would be interesting to hear from someone such as an enthusiast, controller or pilot that's familiar with this airspace. Are there speed restrictions or is this airspace managed differently? Also, does the fact that we were taking off towards international airspace / waters / etc. make a difference of some sort?

I'm quite curious because we took off during a departure bank, so the airspace was not quiet with a few aircraft flying our same airways towards the Philippines (our direction towards the US)

Thanks ahead of time for your insight!

Best,
-no1racer

KIAS and ground speed are two different things. You can have a significantly different reading on both. Throw a tail wind in there and it’s easy to get a high ground speed. In a C172 or other trainer you can be set up for slow flight and actually be flying backwards while showing a positive IAS.

Can also be weight reasons. Some heavies at a high TOW need a higher airspeed to maintain lift.

jetblueguy22 wrote:

KIAS and ground speed are two different things. You can have a significantly different reading on both. Throw a tail wind in there and it’s easy to get a high ground speed. In a C172 or other trainer you can be set up for slow flight and actually be flying backwards while showing a positive IAS.

Can also be weight reasons. Some heavies at a high TOW need a higher airspeed to maintain lift.

Thanks jetblueguy22, absolutely they are two different things. I don't have the KIAS, so I posted what I have in ground speed.

However, as you can see on the UAL2 flight, the ground speeds are significantly higher at 450 MPH for 10,000ft. This can't be explained by tailwind alone. There's something else behind it.

Appreciate your quick reply and look forward to other contributions.

Best,
- no1racer

According to my Jeppesen, in the Singapore FIR, the 250knots/10,000 only applies to arrivals. Also, 250 KIAS is 288KTAS at 10,000’ on standard day, plus/minus any wind for ground speed.

A heavy 744 or 777 will climb better at 320-340 KIAS, so if allowed, will do so.

"250 below 10" as a hard limit is rather a North American thing.

In general, in the region in question, there is a speed limit of 250kn under 10000 feet, at least for arrivals. However, it is a rather "soft" limit. Being approved for "high speed below ten," getting "speed at your discretion," or having to "maintain 270 knots until xxxxx" is very common.

On departure, you might be given free speed because the controller knows you'll typically speed up and get out of their way.

If you get significant track shortening on arrival, typically the easiest thing to do is "request high speed" and maintain 280-300 knots to get back on profile.

Our ops manual says we must be at 250 knots or less below 5000ft, and that is a hard limit for us.

Although 250 below 10,000 is a thing in the United States, if a heavy jet needs it, they can be approved for a high-speed climb.

In the US, 250/10,000’ is pretty hard limit, ATC cannot approve “high speed” like they can in other parts of the world. It has been accepted that heavies, esp 747 and 777, can climb at the lowest IAS for the clean configuration, often about 280, BUT, the FAA General Counsel did publish a ruling stating that operating above 250 merely because that’s min clean isn’t legal.

GalaxyFlyer wrote:

According to my Jeppesen, in the Singapore FIR, the 250knots/10,000 only applies to arrivals. Also, 250 KIAS is 288KTAS at 10,000’ on standard day, plus/minus any wind for ground speed.

A heavy 744 or 777 will climb better at 320-340 KIAS, so if allowed, will do so.

Starlionblue wrote:

"250 below 10" as a hard limit is rather a North American thing.

In general, in the region in question, there is a speed limit of 250kn under 10000 feet, at least for arrivals. However, it is a rather "soft" limit. Being approved for "high speed below ten," getting "speed at your discretion," or having to "maintain 270 knots until xxxxx" is very common.

On departure, you might be given free speed because the controller knows you'll typically speed up and get out of their way.

If you get significant track shortening on arrival, typically the easiest thing to do is "request high speed" and maintain 280-300 knots to get back on profile.

Our ops manual says we must be at 250 knots or less below 5000ft, and that is a hard limit for us.

Thanks GalaxyFlyer and Starlionblue for both of these answers! It gives a lot of context and adds to the answer I'd received before. So, our 787-9 could have a climb profile that's better suited to a higher speed. Our climb out was quite shallow, but I was still surprised with how quickly we accelerated. It's pretty cool to be going so fast so low.

So, is the arrival restriction more because the arrival spacing is the more important?

AirKevin wrote:

Although 250 below 10,000 is a thing in the United States, if a heavy jet needs it, they can be approved for a high-speed climb.

GalaxyFlyer wrote:

In the US, 250/10,000’ is pretty hard limit, ATC cannot approve “high speed” like they can in other parts of the world. It has been accepted that heavies, esp 747 and 777, can climb at the lowest IAS for the clean configuration, often about 280, BUT, the FAA General Counsel did publish a ruling stating that operating above 250 merely because that’s min clean isn’t legal.

Thanks for the clarification on that. I'd be interested to know why it's such a hard limit. Is it because of close calls or some type of past set of issues / incidents? Really curious and thanks for all of the great replies!

Best,
- no1racer

In the ‘60s, there were series of mid-airs involving high speed airliners and GA planes that led to the regulation. Four in 67 and 68, plus the NYC collision between UA and TWA. At the time, no speed rules, so it wasn’t unusual to fly at 300+ at low altitudes.

As GalaxyFlyer knows well, military aircraft that routinely fly faster (fighters) are pretty much exempt from that rule when coming in to land. (300-350 IAS on initial, VMC). This even applies to joint use airports where many ANG units are stationed.

RetiredWeasel wrote:

As GalaxyFlyer knows well, military aircraft that routinely fly faster (fighters) are pretty much exempt from that rule when coming in to land. (300-350 IAS on initial, VMC). This even applies to joint use airports where many ANG units are stationed.

That’s very true, but those speeds are in the -1 and really minimum operational speeds. Try coming down initial at 450 at a civilian ANG base, it might raise some eyebrows.

GalaxyFlyer wrote:

RetiredWeasel wrote:

As GalaxyFlyer knows well, military aircraft that routinely fly faster (fighters) are pretty much exempt from that rule when coming in to land. (300-350 IAS on initial, VMC). This even applies to joint use airports where many ANG units are stationed.

That’s very true, but those speeds are in the -1 and really minimum operational speeds. Try coming down initial at 450 at a civilian ANG base, it might raise some eyebrows.

True, but then there were the VR (low level) routes which we used to fly at 400kts IAS at 500 feet AGL. I believe many of those were in uncontrolled airspace. You wouldn't find any airliners down there, but there was the occasional puddle jumper near miss.

I'm based out of Changi flying the 787. 230kts below 4000 and 250kts below 10,000 are published speed restrictions for all the SIDs, whilst most STARs would have you slow down to 250kts and 220kts much further out.

That being said, the departure speed restriction is usually waived by ATC, either on request or usually without even asking. Arrival speed restrictions are enforced whenever traffic is heavy, but it is common to be told to maintain 280kts even below 10,000ft. Company policy is max of 250kts below 5000 regardless.

I don't fly to Indonesia or Malaysia that often, though on the few occasions I've been into KUL and DPS, never had any issues with speed control.

RetiredWeasel wrote:

GalaxyFlyer wrote:

RetiredWeasel wrote:

As GalaxyFlyer knows well, military aircraft that routinely fly faster (fighters) are pretty much exempt from that rule when coming in to land. (300-350 IAS on initial, VMC). This even applies to joint use airports where many ANG units are stationed.

That’s very true, but those speeds are in the -1 and really minimum operational speeds. Try coming down initial at 450 at a civilian ANG base, it might raise some eyebrows.

True, but then there were the VR (low level) routes which we used to fly at 400kts IAS at 500 feet AGL. I believe many of those were in uncontrolled airspace. You wouldn't find any airliners down there, but there was the occasional puddle jumper near miss.

I’d forgotten VR and IR routes, yes, 420 in the Hun usually, unless fuel was an issue. It’s not blowing off the 250 restriction, an exception in the regs. In A-10s, we flew low levels at 250 unless in SUA.

no1racer wrote:

GalaxyFlyer wrote:

According to my Jeppesen, in the Singapore FIR, the 250knots/10,000 only applies to arrivals. Also, 250 KIAS is 288KTAS at 10,000’ on standard day, plus/minus any wind for ground speed.

A heavy 744 or 777 will climb better at 320-340 KIAS, so if allowed, will do so.

Starlionblue wrote:

"250 below 10" as a hard limit is rather a North American thing.

In general, in the region in question, there is a speed limit of 250kn under 10000 feet, at least for arrivals. However, it is a rather "soft" limit. Being approved for "high speed below ten," getting "speed at your discretion," or having to "maintain 270 knots until xxxxx" is very common.

On departure, you might be given free speed because the controller knows you'll typically speed up and get out of their way.

If you get significant track shortening on arrival, typically the easiest thing to do is "request high speed" and maintain 280-300 knots to get back on profile.

Our ops manual says we must be at 250 knots or less below 5000ft, and that is a hard limit for us.

Thanks GalaxyFlyer and Starlionblue for both of these answers! It gives a lot of context and adds to the answer I'd received before. So, our 787-9 could have a climb profile that's better suited to a higher speed. Our climb out was quite shallow, but I was still surprised with how quickly we accelerated. It's pretty cool to be going so fast so low.

So, is the arrival restriction more because the arrival spacing is the more important?

As I see it, the arrival restriction is not really about spacing per se. It's more an admission of the fact that we are all funneling into the same patch of sky, so unless told otherwise, go slower and there's more time to deal with stuff. On departure, aircraft are all coming from one spot and fanning out from there, so spacing is less of an issue.

One thing to consider as well are bird strikes. Even though most birdstrikes occur very close to the ground (below around 1000/1500ft) there is still a risk of encountering birds below FL100. Obviously, hitting a big bird at high speed is no fun and can cause considerable damage to the aircraft, so this is also a consideration. IIRC, in Indonesia it was quite common to get high speed (I was there around 8 years ago, so things may have changed), but that's the same in Europe. Slightly off topic, but also interesting is that in some countries (mostly in Germany tbh) smaller airports that are using by commercial flights (including 320s, 737s, 747 freighters...) are within airspace class E below FL100, which means that VFR flights are allowed in this airspace and they don't necessarily have to be in contact with ATC and "see and avoid" principle applies there. For this reason it is advisable (in my company it is even a "hard limitation") that the speed is reduced to below 220kts in these airspaces to enable more time to see and avoid traffic.

GalaxyFlyer wrote:

In the US, 250/10,000’ is pretty hard limit, ATC cannot approve “high speed” like they can in other parts of the world. It has been accepted that heavies, esp 747 and 777, can climb at the lowest IAS for the clean configuration, often about 280, BUT, the FAA General Counsel did publish a ruling stating that operating above 250 merely because that’s min clean isn’t legal.

Wasn't there something in that interpretation that also said something about "normal configurations in the climb?" I recall one area of pushback being that some planes' published climb profiles don't include a dirty config, and hence they argued that they had to be clean because flaps out would be an unapproved condition, so they could go faster under 91.117(d).

That might, I haven’t read it in years. Frankly, between bird strike potential, GA traffic, I don’t see a lot of reason to be faster than 250 or min clean to 10,000’.

no1racer wrote:

So, is the arrival restriction more because the arrival spacing is the more important?

There is also another reason which is often overlooked that is for procedures involving loss of communications. If for any reason an aircraft were to face a loss of communications there are set procedures to be followed which would include following the filed plan, last ATC instruction etc. STARs are known published procedures that aircraft with loss of communications would be expected to follow to an instrument approach and then land, it provides ATC with a predictable 4D flight path even in the event of loss of communications.

ATC do have the authority to vary the speed below 10,000 ft in these regions, I have in ancient times before the fun police got involved flown in excess of 300 kts on downwind for 02 at SIN.

RetiredWeasel wrote:

As GalaxyFlyer knows well, military aircraft that routinely fly faster (fighters) are pretty much exempt from that rule when coming in to land. (300-350 IAS on initial, VMC). This even applies to joint use airports where many ANG units are stationed.

Civil aviation rules do not apply to state aircraft eg military.

LH707330 wrote:

Wasn't there something in that interpretation that also said something about "normal configurations in the climb?" I recall one area of pushback being that some planes' published climb profiles don't include a dirty config, and hence they argued that they had to be clean because flaps out would be an unapproved condition, so they could go faster under 91.117(d).

Not that I am aware of, the limit does not apply 12 miles offshore, and operators that need this relaxed elsewhere would have a specific approval from the administrator in their OpsSpec, it would be a common inclusion for any flag carrier or international carrier operating long haul flights out of the US. ATC is not the administrator, they cannot authorize the variation to this rule.

In the US anyway, the DoD requires us to follow State rules, including the FARs and any ICAO SARPs as incorporated into national aviation authority. The only exception obviously is actual combat or very specialized activities over the high seas, carriers for example.

Our flight rules are identical to FAA Part 91, example. Yes, the authority comes from the DOD and not the FAA, functionally there’s no difference.

Due Regard Is a thing, but military operations have to follow civil rules in peacetime over sovereign territory to meet the intent of exercising due regard to civil air navigation.

no1racer wrote:

[quote="jetblueguy22"

However, as you can see on the UAL2 flight, the ground speeds are significantly higher at 450 MPH for 10,000ft. This can't be explained by tailwind alone. There's something else behind it.

Yes, it most certainly can be explained by tailwind alone. Unless the flight crew broke the limit during climb.

At F100, 320 KIAS is 362 KTAS, so you’d only 37 knots of tailwind to have ground speed of 399 knots. If the crew the leveled off at F100 to accelerate from min clean of around 270 KIAS, this is very explainable.

GalaxyFlyer wrote:

In the US anyway, the DoD requires us to follow State rules, including the FARs and any ICAO SARPs as incorporated into national aviation authority. The only exception obviously is actual combat or very specialized activities over the high seas, carriers for example.

Our flight rules are identical to FAA Part 91, example. Yes, the authority comes from the DOD and not the FAA, functionally there’s no difference.

Due Regard Is a thing, but military operations have to follow civil rules in peacetime over sovereign territory to meet the intent of exercising due regard to civil air navigation.

Article 3 of the 1844 Chicago convention

“ Article 3
Civil and state aircraft
a)This Convention shall be applicable only to civil aircraft, and shall not be applicable to state aircraft
b)Aircraft used in military, customs and police services shall be deemed to be state aircraft.”

The C in ICAO is civil.

Do military pilots have a current FAA medical licence or medical ?

GalaxyFlyer wrote:

In the US, 250/10,000’ is pretty hard limit, ATC cannot approve “high speed” like they can in other parts of the world. It has been accepted that heavies, esp 747 and 777, can climb at the lowest IAS for the clean configuration, often about 280, BUT, the FAA General Counsel did publish a ruling stating that operating above 250 merely because that’s min clean isn’t legal.

Do you have a source for this? In ANC we have a lot of heavy traffic (both foreign and U.S. carriers) and the foreign carriers are always requesting "high speed climb" on departure, which is always approved. The American carriers don't bother asking probably because we are all under the impression that we are covered by 91.117(d) and I have never heard of a crew being violated for 250 below 10k on departure.

zeke wrote:

GalaxyFlyer wrote:

In the US anyway, the DoD requires us to follow State rules, including the FARs and any ICAO SARPs as incorporated into national aviation authority. The only exception obviously is actual combat or very specialized activities over the high seas, carriers for example.

Our flight rules are identical to FAA Part 91, example. Yes, the authority comes from the DOD and not the FAA, functionally there’s no difference.

Due Regard Is a thing, but military operations have to follow civil rules in peacetime over sovereign territory to meet the intent of exercising due regard to civil air navigation.

Article 3 of the 1844 Chicago convention

“ Article 3
Civil and state aircraft
a)This Convention shall be applicable only to civil aircraft, and shall not be applicable to state aircraft
b)Aircraft used in military, customs and police services shall be deemed to be state aircraft.”

The C in ICAO is civil.

Do military pilots have a current FAA medical licence or medical ?

Do you contend that military are at liberty to disregard civil rules? Yes, as I said, the authority doesn’t come from civil authority, but every competent military flight operation follow the same rules as civilians. In the US, that means our flight rules are identical to FAR 91. I’ve been in USAF Flight Standards, the USAF a manual references every bit of FAR 91 or ICAO SARPs. No, we don’t have FAA certificates, but military pilots have had their civilian certificates under enforcement action due to FAR violations while operating military aircraft. Famously, an airline
ANG pilot who thought he could use a non-approved NAV system in his F-16 caused loss of separation in US airspace.

USAF Advanced Instrumrnt Instructor School spent about 2 hours on Chicago Convention, before delving into the details of operating state aircraft.

ArcticFlyer wrote:

GalaxyFlyer wrote:

In the US, 250/10,000’ is pretty hard limit, ATC cannot approve “high speed” like they can in other parts of the world. It has been accepted that heavies, esp 747 and 777, can climb at the lowest IAS for the clean configuration, often about 280, BUT, the FAA General Counsel did publish a ruling stating that operating above 250 merely because that’s min clean isn’t legal.

Do you have a source for this? In ANC we have a lot of heavy traffic (both foreign and U.S. carriers) and the foreign carriers are always requesting "high speed climb" on departure, which is always approved. The American carriers don't bother asking probably because we are all under the impression that we are covered by 91.117(d) and I have never heard of a crew being violated for 250 below 10k on departure.

Sure, Seltzer/Continental Airlines.

https://www.faa.gov/about/office_org/he ... tation.pdf

I doubt anybody gonna be violated, but the question was asked and the GC said, “”configuration is up to the pilot to comply with 91.117”.

Note it addresses the application of 91.117 as it applies to military aircraft. BTW, many fighters didn’t have anti-collision lighting until the FAA required which was then installed on non-compliant aircraft. Huns didn’t have rotating beacons and the “old heads” would tease ‘em, “look a fire engine just taxied by”.

GalaxyFlyer wrote:

ArcticFlyer wrote:

GalaxyFlyer wrote:

In the US, 250/10,000’ is pretty hard limit, ATC cannot approve “high speed” like they can in other parts of the world. It has been accepted that heavies, esp 747 and 777, can climb at the lowest IAS for the clean configuration, often about 280, BUT, the FAA General Counsel did publish a ruling stating that operating above 250 merely because that’s min clean isn’t legal.

Do you have a source for this? In ANC we have a lot of heavy traffic (both foreign and U.S. carriers) and the foreign carriers are always requesting "high speed climb" on departure, which is always approved. The American carriers don't bother asking probably because we are all under the impression that we are covered by 91.117(d) and I have never heard of a crew being violated for 250 below 10k on departure.

Sure, Seltzer/Continental Airlines.

https://www.faa.gov/about/office_org/he ... tation.pdf

I doubt anybody gonna be violated, but the question was asked and the GC said, “”configuration is up to the pilot to comply with 91.117”.

Note it addresses the application of 91.117 as it applies to military aircraft. BTW, many fighters didn’t have anti-collision lighting until the FAA required which was then installed on non-compliant aircraft. Huns didn’t have rotating beacons and the “old heads” would tease ‘em, “look a fire engine just taxied by”.

That's quite interesting although it doesn't exactly address 91.117(a) a.k.a. 250 kts below 10,000. While an arriving aircraft would hardly be justified in not simply configuring to comply with speed restrictions (either regulatory or ATC-assigned), departing aircraft (to my knowledge) do not factor into their fuel planning the prospect of dragging flaps all the way up to 10,000 feet. I'd be interested to see if the FAA has ever addressed that scenario specifically; I'm sure everyone is afraid to ask since right now no one seems to care in practice.

Exactly! The FAA, being the FAA, would probably rule 250 knots means 250 knots, period. Flaps 1 to 10,000’.