Hey guys. Really quickly, (I apologize if this question has been asked: I looked back 3 pages to see if anyone asked the same thing, but it didn't look like it) is it possible to get ATC to stop giving me this command?

 

An hour ago I did an approach into JFK and I got the "Descend to 12,000. Start down now please I need you down in 20 miles or less." - I know what that means, it means idle thrust, full speed brakes and maximum descent rate. In the B738, however, it's hard to do more than 2500 ft/min descent rates without gaining more speed than you can handle.

 

I busted the altitude restriction at a -2700ft/min descent rate. That's absurd. Is there any way to stop ATC from demanding this type of action from me, or any way I can just reply with an "Unable to comply" response? I hate getting a bad score at the End Of Flight Critique (And a call to FISDO) because my aircraft can't descend like the Space Shuttle. Thanks for any help!

You should get an option to report that you are unable to comply, when you say that, you usually get something along the lines of 'okay, well, do the best you can'.

 

Al

you can put a vor within 5 miles of the airport.

 

jd

You should get an option to report that you are unable to comply, when you say that, you usually get something along the lines of 'okay, well, do the best you can'.

 

Al

 

Al,

 

In that case I've been pretty silly about this. I let my Co-Pilot do the talking and I guess he and I don't agree on what the 738 can do. I'll try manual coms the next time I descend and see if I get the option; Thanks for the heads up Al!

you can put a vor within 5 miles of the airport.

 

jd

 

Never thought about that. I actually may just start doing that.

 

Thanks for the quick advice. Going to try both suggestions out next flight.

The crossing restriction is at 12,000 or 11,000 depending on your arrival heading at 40 nm out. You need to plan ahead for this.

 

To help plan for this if you are using a Boeing (Smith's) type FMC like in the PMDG or possibly the IFly models, go to the FIX page, enter the ICAO code, and the for the place/bearing distance enter /40 and EXE.

 

On the nav display you will now see a range ring around the airport . Use MCP V/S, speed reduction, and spoilers, if necessary, and then the descent arcs will tell you if you'll make it in time.

 

RC uses the 3:1 descent estimate to establish the TOD to the crossing restriction altitude, not surface altitude, so if you use pilot's discretion to delay your descent you take your chances. The TOD in the nav display uses the surface altitude and therefore will start you down later than RC's TOD. If you place a fix with a hard altitude on your LEGS page then the TOD in the nav display will change accordingly.

 

http://flightaware.com/live/airport_status_bigmap.rvt?airport=KJFK

 

and watch for a while the incoming aircraft. Those that are too high are coming in on a long wide downwind dropping swiftly. RC probably had you appropriately at around 17,000 fifty or so miles out and that's plenty of time to drop to 12,000 when you got the command.

 

In planning ahead you can ask RC before the approach phase for a lower altitude while in center.

I don't ever recall hearing "I need you down in 20 miles or less". I hear "30 miles or less" which results in a descent rate around 2000fpm with no speed brakes.

I usually stall ATC before answering.

I get this messsage each flight and they tell me when I'm far enough away that I get down to the altitude givin to me way before 30 miles and I can descend at 1800fpm

Same here. The key is to control your descend at an 1800fpm from the ATC-requested TOD. You can comfortably use that rate all the way.

FYI:

 

The NOTAMS flexibility option does not apply to the crossing restriction. It remains strict.

 

In general if you are not near a checkpoint start your aircraft descending before acknowledging the command to save a small bit of time.