Why can airlines expect their flight level 10 minutes after departure? why exactly ten minutes?

Answer 1

By that time they are nearing the edge of the lower tier of the terminal controlled airspace. They need to keep the aircraft in controlled airspace (IFR rules), so they need to start raising that a/c altitude to get it into the upper tier, so it remains in controlled airspace. By the time they are in the upper tier, they just go ahead and clear it to it;s cruising altitude, so they can start getting better fuel economy (and away from any vfr a/c they might not see on radar).

Answer 2

Patrick misunderstood the question.

The 10 minutes is when the departing aircraft can expect to receive clearance to continue to climb their assigned altitude. Normally a SID dictates a lower level off altitude. In MSP, for example, you initially climb and maintain 7000 feet, and you can expect further clearance to climb 10 minutes after departure.

And yes, ATC can require you to be at a specific altitude at a specific time or place. That's what they do. If you don't tell them "unable" then you will be violated if you don't comply with the ATC instructions.

Answer 3

It's just a sort of 'do not do it yet' sort of directive, usually having just been told "climb and maintain 2000" they check in with departure who immediately say "climb and maintain 15000", or something similar. Very few actually level at 2000, I can only remember tooling around over the south of England in a 747 at a couple of thousand feet on one occasion. They ran us round the M25 then up the M1 to Luton before they cleared us to climb and resume a more normal NNW coarse. It's expensive to fly a big jet around at low level, they burn too much fuel.

Answer 4

The 10 Minutes is just a number... it could be any number, thats just the one they use... It tells the pilot that in the case of a two-way radio failure, they can and should procede to that altitude 10 minutes after departure as stated here.

FAR's Sec. 91.185

(a) General. Unless otherwise authorized by ATC, each pilot who has two-way radio communications failure when operating under IFR shall comply with the rules of this section.

(c) IFR conditions. If the failure occurs in IFR conditions, or if paragraph (b) of this section cannot be complied with, each pilot shall continue the flight according to the following:

(1) Route. (i) By the route assigned in the last ATC clearance received;

(ii) If being radar vectored, by the direct route from the point of radio failure to the fix, route, or airway specified in the vector clearance;

(iii) In the absence of an assigned route, by the route that ATC has advised may be expected in a further clearance; or

(iv) In the absence of an assigned route or a route that ATC has advised may be expected in a further clearance, by the route filed in the flight plan.

(2) Altitude. At the highest of the following altitudes or flight levels for the route segment being flown:

(i) The altitude or flight level assigned in the last ATC clearance received;

(ii) The minimum altitude (converted, if appropriate, to minimum flight level as prescribed in §91.121(c)) for IFR operations; or

(iii) THE ALTITUDE OR FLIGHT LEVEL ATC HAS ADVISED MAY BE EXPECTED IN A FURTHER CLEARANCE.

Answer 5

It is an arbritary time limit that ATC clearance gives the pilot, in case of two-way radio communication failure after takeoff. You hear that on almost every IFR clearance, and that's why.

Answer 6

They can't and it isn't. ATC and the location of the airport dictate the rate of climb on takeoff which would have a direct bearing on when the aircraft level's off.