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Delete VNAV's 240 Knot Speed Limit Below 10,000

Started by emerydc8, Tue, 13 Oct 2020 15:42

andrej

Hi Jon,
thanks for confirming our hypothesis. 8) If anything, PSX is a must have for any pilot (especially for Boeing drivers).
Andrej

emerydc8

With regard to maintaining the last speed on a STAR, it looks like Atlanta ATC was correct.

Quote
NOTE-

Pilots are required to comply with published speed restrictions.

    A speed restriction published as part of a SID/STAR is canceled when an aircraft is vectored off, or a deviation from the SID/STAR is approved. If necessary, assign a speed in conjunction with the vector or approval to deviate.

NOTE-

The last published speed on a STAR will be maintained by the aircraft until ATC deletes it, assigns a new speed, issues a vector, assigns a direct route or issues an approach clearance.

FAA Order JO 7110.65Y - Air Traffic Control
Section 7
5-7-1 SPEED ADJUSTMENT
https://www.faa.gov/air_traffic/publications/atpubs/atc_html/chap5_section_7.html

andrej

Hi Jon,
so, at least in the US, one must always obey ATC. Thanks for confirmation. As I only fly virtual via VATSIM, I tend to obey ATC as such. However, from some YouTube videos, I have noticed that most of the time, even in Europe, pilots follow ATC's instructions (unless directly told that speed is (i) "no factor", (ii) "speed is yours", etc.).

Cheers,

Andrej

emerydc8

Quote from: andrej on Thu, 15 Oct 2020 05:07

My other question is, when to slow down to 220 kts. Immediately after passing WINTA or a few miles prior to reaching SPYSD? I managed my speed via VNAV all the way up to IAF.

Thanks and best!

To answer your question, in this situation, you would hold 250 knots until the minimum distance necessary to slow to 220 by the next fix. At least that's the case in the US. The VNAV on the 767 will usually ratchet down later than it should, often times a mile or two prior to the fix, and then you get the DRAG REQUIRED message.

Jon


andrej

Thanks Jon. So, slowing down "until the minimum distance necessary" to next speed restriction can be achieved by programing the limit speed to the FMC, or manually based on PIC's experience and knowledge of the type, and/or based on decision to slow down at certain point prior to the waypoint.

Unless, one is instructed by the ATC of speed limit.

Very informative and learning experience for me. :)

Cheers!
Andrej

emerydc8

Quote from: andrej on Wed, 28 Oct 2020 08:40
Thanks Jon. So, slowing down "until the minimum distance necessary" to next speed restriction can be achieved by programing the limit speed to the FMC, or manually based on PIC's experience and knowledge of the type, and/or based on decision to slow down at certain point prior to the waypoint.

The limit speed on the STAR is usually coded into the arrival. For whatever reason, it seems that just about every descent I do that contains a crossing speed, I end up having to use speed brakes because VNAV just isn't smart enough to figure out it needs more time to slow, even when we load the descent winds via ACARS. VNAV is a total waste of fuel (at least it is on the 767), and it was sold to the airlines as a way of saving fuel. We consumed less fuel when we used V/S and a 3-1 profile. Go figure.