I've been having an ongoing discussion with several other pilots, and many seem to be on both sides of the question. The problem is if you are close to an airport and ATC left you too high, what do you do first? I tend to slow down and perhaps stop the descent, put out my gear and flaps, and then drop like a rock. Other pilots believe it's better to keep descending, slowly slow down and put gear and flaps down while still going down. As far as the best angle of descent, or losing the most altitude for a given distance, which is better? I know that you can get a much higher descent rate at a higher speed, but you are also moving over the ground much faster. Even the ground you use up slowing down couldn't possibly make up for putting all of your drag out and going down much faster, could it? Is there a way to resolve this question?
I could just try it in the sim, but I was hoping there was a way to figure it out mathematically. Thanks for the help.
PS, I'm talking about large turbojets in this question.
If safety is no concern, as everyone else has said, slow down then extend the flaps and gear. If safety is any concern at all decline the clearance and request an extended down wind or vector for descent. Don't let ATC push you. These kinds of descents can lead to a number of bad things. If for any reason you must level off unexpectedly (VFR nordo traffic, other side traffic enters your final path, etc) you will be very close to stall speed before you get the engines spooled up. Your AC is in a very vulnerable state. The gear take forever to retract and the first thing that happens if you try to retract them is the doors open and the rate of deceleration increases. Some AC have flaps that may retract quickly but if the gear is out the flaps won't be enough. These descents also precede the majority of unstable approaches.
For safety sake some 'old school' gouge still works very well
Below 10, 3000 fpm max to 3000 AGL
Then the max sinkrate is your altitude AGL until stabilized at 1000'
If you are at idle minimum speed is VREF plus 30
The gear
never get extended prior to the FAF on profile or if visual when descending through the pattern altitude - 1500 agl
Most AC can live with this gouge. If you must use some drag for the descent
approach flaps and spoilers should be enough for 3000 fpm. Just remember to add 30 knots or so to the published minimum speed for the configuration.
I have seen both regional and 'mainline' crews fully configure at 10, then start an idle descent at the slowest speed possible. It makes the hair stand up on the back of my neck, my skin crawl, stomach get queasy, and body and mind generally revolt. If any little external, unforeseen factor requires a flight path change you will be between a rock and a hard spot with few choices.
Don't let ATC push you. You don't have to accept the clearance. Too many of our brethren do. And ATC knows better. They are just seeing if you will do it to cover their mistake.
