Speed Restriction and Descents

[Guest EIDUB]

Hi,I was wondering would it be possible to put in an option as to whether ATC issues you a speed restriction of 250KIAS below 10,000ft. I know this is a mandatory speed restriction in the US except for experimental areas in Houston I believe (correct me if I am wrong) but in Europe it is not uncommon traffic permitting to release the speed restriction and give speed discretion to the pilot. Maybe even make it random.Also why not add random late descent clearances. I have a problem with the descent clearance as it never matches any VNAV predictions from the FMC of PIC767 and PMDG737. However I saw this topic mentioned before and it was explained that a formula is used to calculate TOD. Fair enough. Would it not be interesting to add a switch to allow late descents though?Can we expect any future updates to RC3.Thanks for a great product,Stephen

[jd 57]

working on future updates as we speakif the boss says 250 can be optional between 10000, i can put it in. maybe i can tie it to rsvm (or is it rvsm LOL)the problem with randomizing the descent clearances, most people i think will end up never making their crossing restriction. then that will be a problem.but i'll think of if there is a way to make everyone happyjd

[Guest EIDUB]

JD,Thank you for your prompt and informative reply. Regards,Stephen

[Guest Scott Campbell]

Around these parts the speed restriction is at the discretion of the Center/APC controller. Pilots are frequently being told something like, "Expect the Pikes1 Arrival. You can ignore the speed restriction." Or if there's not a specific STAR inbound point, then just toldd to cross a specific intersection at altitude and ignore the restriction(s).Oh, and...Reduced Vertical Separation Minimum ;-) (sorry, had to do that).

[PeteP 2]

That's good news, jd. Just in case you find a way to do it, here are the rules for the UK:CAP 493 Manual of Air Traffic Services Part 13 Speed Limit3.1 Airspace Speed Limits and Procedure Speed Limits are two types of speedrestrictions which may apply to certain flights.3.2 Airspace Speed Limit3.2.1 The Rules of the Air Regulations require aircraft flying below FL100 to observe, withexceptions, a speed limit of 250 kt IAS. Such a limit is an essential component of the'see and avoid' principle when separation is not established by ATC. This is in additionto other speed limits, see below, which may be notified for a specific airspace.The 250 kt speed limit does not apply to:a) flights in Class A and B airspace;:( IFR flights in Class C airspace;c) flights in Class C and D airspace when authorised by an air traffic control unit;d) test flights in accordance with specified conditions;e) aircraft taking part in flying displays when authorised by the CAA;f) aircraft subject to a written permission granted by the CAA;g) aircraft not subject to the Air Navigation Order (e.g. Military aircraft).3.2.2 Controllers may only exercise the authority granted in paragraph c) above when theyare satisfied that they are in contact with all aircraft in the relevant part of the airspace.VFR flights in the vicinity are to be warned about aircraft flying at a higher speed.3.2.3 An airspace speed limit must not be relaxed by ATC for flights which will be transitingfrom a known traffic environment, Class A airspace for example, into airspace wherethe 'see and avoid' principle operates as the primary means of separation.3.2.4 In Class E, F and G airspace, conflicting traffic may not be known to ATC and so it isnecessary for all flights to make use of the see and avoid principle. In order for this tooperate effectively, controllers shall not authorise a relaxation of the airspace speedlimit.3.3 Procedure speed limits3.3.1 In certain cases, speed limits are published for specific ATC procedures for a numberof reasons. For example:a) A speed limit of 250 kt is applied to published Standard Instrument DepartureProcedures to assist in the initial provision of separation between successivedeparting aircraft;:( A speed limit of 250 kt is applied to some Standard Arrival Route procedures toassist ATC in the integration of traffic flows;c) Some holding patterns have non-standard maximum holding speeds forcontainment within controlled airspace or separation from adjacent routes orprocedures;d) Some instrument approach procedures have non-standard maximum speeds forobstacle avoidance or controlled airspace containment.3.3.2 When an aircraft is in receipt of a radar service, except for instrument approachprocedures, controllers may relax procedure speed limits. However, extreme cautionshould be exercised as the controller then becomes responsible for the provision ofseparation, controlled airspace containment and obstacle clearance which wouldotherwise have been provided within the speed limited procedure design.3.3.3 Controllers should also be aware that even if there is no tactical ATC requirement tosustain a speed limit, particularly for departing aircraft, the pilot remains responsiblefor operating his aircraft in such a manner as to adhere to other requirements such asnoise preferential route track-keeping.Good luck! :-):-):-)Pete

[Guest Tim W]

And from a radio point of view, the call would be "Speedbird 555, climb flight level seven zero, no speed restriction"., often shortened to "No speed" or "The speed is yours".RegardsTimhttp://www.cambridgeflyingclub.com/images/timavatar2.gif

[PeteP 2]

the call would be "Speedbird 555, climb flight level seven zero, no speed restriction"Almost, Tim. The correct phrase is, "no ATC speed restriction. The "ATC" part is included to ensure the pilot is not mislead into believing he is released from the responsibility of flying speeds which will still allow him to comply with noise preferential route track-keeping etc, as in para 3.3.3 above.Pete