To Ray or any other RC4 user - RC4.3 Controller (P3Dv5.4) commands initial descent earlier than FMC/CDU calculated T/D.  The manual indicates it is possible to advise controller that we are unable to descend at present by selecting option #3 from the menu.  However, I never see an option 3, only 2, 4 & maybe 5.  I've tried both with NOTAMS box on arrival airport checked and unchecked without the option appearing in the menu.  

I've just been ignoring controller's commands to descend and once the a/c begins descent as per the FMC VNAV path, controller stops nagging me.  Is there any way around this, or am I doing something wrong/missing something?

Kindest regards,

Glenn

Edited February 27, 20242 yr by beechcaptain
typo error correction

Hi Glenn,

By a sheer coindence I've just been cleared lower before the ToD in my PMDG737 inbound to LAX.

The answer is to ack and initiate the shallowest descent that keeps RC4 happy. 200fpm in v/speed mode.

When the PMDG ToD point is reached initiate VNAV and monitor your speed and descent rate. I usually engage the SPD INTV option so the speed remains constant.

If you can set an altitude constraint in the CDU for the 40nm point that will ease the workload.

10 minutes ago, Ray Proudfoot said:

200fpm in v/speed mode.

For regulation:

 When ATC has not used the term 'AT PILOT'S DISCRETION' nor imposed any climb or descent restrictions, pilots should initiate climb or descent promptly on acknowledgement of the clearance. Descend or climb at an optimum rate consistent with the operating characteristics of the aircraft to 1,000 feet above or below the assigned altitude, and then attempt to descend or climb at a rate of 500 feet per minute until the assigned altitude is reached. If at anytime the pilot is unable to climb or descend at a rate of at least 500 feet a minute, advise ATC

Thanks for the info, Ray & polosim.  I would normally just select DES NOW in my PMDG a/c and let VNAV control the slower descent rate, usually 1000 fpm until the T/D is reached then it will descend at various fpm rates to meet crossing restrictions in the STAR.  However, the FMC in the Capt Sim 757 III is a bit antiquated compared to the PMDG 737NGXu a/c and I prefer to let its VNAV initiate descent at its calculated T/D.  I don't tend to fly the 757 much, as I prefer the PMDG a/c, so I just wanted to see if there was a better solution.

 

@polosim, there was no pilot discretion on my flight today. I find I only get that on lower cruise levels.

My plan is always to stay as high and fast for as long as possible before initiating a descent. Because RC4 always wants you down earlier than the calculated ToD this procedure is unavoidable.

Glenn, if you program your altitude required 40nm out that will also work although you’re descending at a greater rate.

If you don’t incur the wrath of RC4 controllers you’re doing a good job. 👍

1 hour ago, Ray Proudfoot said:

If you don’t incur the wrath of RC4 controllers you’re doing a good job. 👍

Well, I suppose in a way it is better to incur Ray's wrath as a controller rather than as a Moderator!