My head is now in the books to get my mind back into the sky before my body goes into the simulator.
Did you remember that if you're more than 200 miles from the airport, and ATC descends you to a lower altitude, you'll lose your descent path indicator... ie., the Chinese glideslope?
When you descend to a lower altitude prior to 200 miles, the airplane re-cruises you at that lower altitude. Operationally this means that you are still in the cruise phase, and the decent path indicator disappears.
While there are other means to in assist descent planning, if you want this tool back in your tool kit now, all you need to do is go the performance page and put in an altitude above the altitude you're cruised at. This puts you back into the descent phase.
Another note on descending...
You're at FL340, and you're supposed to be at intersection HAPPY at 10,000 at 250 KTS, but ATC descends you to FL300. Remember the path has drawn a straight line from FL340 to HAPPY. You've just been cleared down to 300. To get the descent path indicator to provide good information you'll need to take the HAPPY constraints out. Then, when level at 300 put them back in. Your straight line, your path, will be recalculated from your present altitude to HAPPY's constraints.
Enjoy the Journey!
Funny how Airbus computers seem to work fairly differently from Boeing's.ReplyDelete
If you start an early descent, will it give you a reduced rate of descent until you reach the original calculated descent path?
If it thinks you're descending to a new cruize altitude and lets say you were really close to your TOD, if you reduce your rate of descent, at some point you should reach your original descent path, would it capture it at this point?
Wow, tricks of the trade! Maybe the computer could generate these guidelines for pilots as they're flying??ReplyDelete
Hi GolfCharlie... yes, they are a bit different from Boeing for sure.ReplyDelete
When ATC say's go descend now... new alt... we use open descent if the descent isn't at our planned descent point because in managed nav, it waits to start down until that magic profile point. Open goes now, and with idle thrust.
But, the bus may deviate from the planned speed and vertical profile in managed nav because of some factors: the actual winds are different from the forecast winds inserted in the MCDU, use of anti-ice (engine idle speed has been increased), or a modification of the lateral flight plan.
Then, if the aircraft is not on the vertical path, the FMS calculates a point where it will intercept the path displaying an intercept symbol at that point along the ND flight plan line.
If the intercept symbol is blue then the path will capture upon interception.
If the path intercept symbol is white the path will not be captured.
So back to your question about the different rate of descent. If the aircraft is below the vertical path she will descend at a constant vertical speed of either 1000 ft./min or 500 ft./min.
The 500 ft/min rate will be used if the aircraft is within 5000 feet of the destination airport elevation or below the highest altitude at which a descent speed limit exists, for a rate protection.
Can you do a shallow descent and capture the path on your own? Yes... in vertical speed. You can monitor your path and create whatever rate. Oh... remember that "white" intercept symbol? Well, that would occur if you're in vertical speed. It won't intercept and fly right on over. But, all you need to do is put it back in managed nav at that point.
The problem with V/S is that it will fly you away from the altitude in the MCP. That's not really a good thing, thus I never like to use it. Murphy's rule is the second you think you're watching then ATC calls, a frequency change... some distraction.
Thanks for the great question!
Thanks Linda, this computer is so smart... but it still can't out think the power of what a human will do. If we could figure out an absolute for every situation we'd be millionaires!ReplyDelete
I had no idea that pilots needed three takeoffs and landings to stay current. Although, I suppose it makes sense. So sorry that you have to hit the books though!ReplyDelete
Thanks Karene, this is exactly the answer I was looking for. Very well explained! Are you a Training Captain or do you consider becoming one?ReplyDelete
Now I think about it, it is not so much different from Boeing's philosophy. Both have their own way of doing things but in the end you have pretty much the same options available, just presented in different ways.
I know you regularly fly to Europe, it would be great to meet in an airport. I am awaiting a new base from my airline, probably in Spain or in the United Kingdom. I believe you fly to major airports only, is that correct? (AMS, BCN, LHR, CDG, ...)
Always a pleasure to read your posts, looking forward to reading your book.
I am so confused.ReplyDelete
I've always done VS mode for descents and the guys that teach us tell us it's better but maybe because different modes/levels of automation.
No VNAV mode, just advisory usually and it'll give it in vertical speed.
They have told us about the idle descents though, I'm still trying to put two and two together!
*Runs to the (CRJ200) sim*
I'd play around with that thing as long as they give me access to it!
Happy landings!...oh and takeoffs too those are important, sometimes overlooked! :)
GolfCharlie, Thank you so much for the kind compliments. Yes... my past life included 21 years of teaching: 737, 757/767, and 747 aircraft. I love it. Would love to on the Bus too, but the new world of transitioning to Non-seniority pilots is making the commute and ability to teach a challenge. I love it however.ReplyDelete
Yes... I fly to AMS, BCN, and CDG. I'll keep you posted when I head that way. On reserve, one never knows. Thanks again for your great comment. And I'm looking forward to your reading my book too!
Ramiel, not to worry and don't be confused. Using V/S for a highly automated airplane is just not utilizing the technology very well. It works, but the protections aren't there that you will have in other modes. I'm not sure on the CRJ200. But I do know... there is more than one way to skin a cat (a saying from the US... I would never do that!) and there is more than one way to fly the automation. Thanks for the comment! And...if you say you're confused, you are entering the world of glass.ReplyDelete
Thanks Heather, I am always hitting the books! But it's fun... I just need more time.ReplyDelete
haha yes. exciting though,ReplyDelete
like at first it was counter intuitive, seeing the red tape on the airspeed, instincts say to move away from it, if its low speed to go up, or high speed to go down, but it's actually the opposite
but yes, exciting times!!
and no don't skin anything, unless your life is dependent on it!
(as per my survival training :P)
Yes, this is exciting times. Ha ha... I'm not skinning anything... except for my knees with the kids.ReplyDelete
As an experienced pilot trainer, you're well ahead of the curve when someone asks, "What's it doing now?" or some such. I think - understanding the what, why and how of those super-smart airplanes is the mark of a seriously good pilot. Some do and and some do not. From a SLC type, thanks for knowing! -CraigReplyDelete
Thank you Craig! I come from old school where we had to know the why and the how... today's world, with the automation, instructors say, "you don't need to know that." But I agree with you... we need to know why, and we'll be prepared when something goes wrong.ReplyDelete
Thanks for the comment.
Can you intercept the vertical path in open descent?ReplyDelete