How does a PILOT KNOW when to DESCEND? Descent planning explained by CAPTAIN JOE

, , 98 Comments


Dear friends followers,
welcome back to my channel and to a very important topic you are most
likely going to mess up at least once in your pilot career – descent planning. How does a pilot know when to initiate his
descent towards its destination aerodrome? This is today’s question. So I’ll show you a few thumb rules Which will make your descent a lot
easier and avoid coming in hot and high. So get your brain ready for some easy
head calculations and let’s get started! [Music]
[ATC]
[Jet taking off] This is undeniably one of the
procedures every pilot messes up at least once in his pilot
career – – the descent planning. Tell me about it, transitioning on to the Boeing 747, which is heavy as lead and fast as a
bullet, will slap you in the face if you think you can fly her like an
Airbus A320, which has a glide ratio comparable to a flying piano
once you extend to speed breaks. There is only little room to play with
once you fly a wide-body airplane. But how is it done? Okay, the times where you flew
inbound to your destination airport and just look outside of the
window and then decided to descend visually towards the runway are over,
at least within the airline industry. Now you might have seen these abbreviations
and videos about a navigation display This shows the top of
descent point in regards to the entered flight plan in the FMGS on
Airbus models or on the FMS on the Boeing. Obviously, this is a great help showing you
when to start your descent, but there is a big flaw with that top of
descent point on the ND and I’ll show you in an example why and why it is important to me that YOU know a few thumb rules to
NOT mess up your approach. Now, let’s assume we’re approaching
into Hamburg, Germany. Now we’ve got the approach set up, but as you see here on those two ND’s, the top of descent points
are at different locations. How can that be? Now this ND shows a direct
approach towards runway 33, and the other includes a
so-called “transition”. A transition is an approach procedure in order to slow down incoming traffic and makes it easier for the approach
controller to stack the planes, or as they say, “pushing tin”, before handing them over
to the tower controller. So with a transition, the
flight or approach distance moves the top of descent to a later point, compared to a direct approach,
which will want you to descend earlier, as you only have a
certain distance left over. This makes sense, right? Compare it as if you were driving
to your girlfriend’s house and she wants you to call her 30
miles prior reaching the house to get dinner ready. Now, you are on a direct
route, but let’s say [that] you need to perform a little detour, or a Transition, at your
ex-girlfriend’s house, that would move your time of call, or top
of descent, to a later point, right? So in order to anticipate that the controller
MIGHT take you in for a direct apporach, always plan with the SHORTEST
distance to the runway. Now, the easiest way of finding
out the distance to the airport is by tuning in the closest VOR DME
to the runway you’re flying to. So in our case, Hamburg has a DME station
named Alster right at the aiport. So we’re gonna be tuning into Alster (ALF)
and [it] will give us a distance of. Now, as you see on the PFD
and ND, we’re at 27,000 feet with a speed of 320 knots,
and a tailwind of 20 knots. Let’s neglect weight of
the plane for a moment. So with that data we want to
calculate the distance we need to fly a continuous descent profile. So the first thing we’re gonna look at is
the altitude we’re gonna have to lose. Now, Hamburg is at 53 feet above sea level, we can disregard that, so we effectively have
to descend 27,000 feet. Now, keep in mind in your airport
destination is Bogotá, for example, you would have less altitude to lose as
the aiport already is at 8,300 feet. So, we’re gonna cross out the last
digits and divide that by 3, so 270 divided by 3 equals 90. So 90 nautical miles is the MINIMUM
distance we’ll need for our descent. Now, the next factor to consider is speed, as there will be no way we’ll be
landing the plane at 320 knots. Now we’ll consider 200 knots
as an average descent speed as you are progressively getting
slower over the entire descent profile, including company speed restrictions
like 250 knots bellow 10,000 feet. But I’ll come back to that in a minute. So we’ve got to lose 120
knots indicated air speed, not ground speed, and a good estimate for most planes is 1
nautical mile per 10 knots speed reduction. So, 120 knots divided by 10 equals 12
nautical miles to reduce the speed. Last, but definitely not
least, and often forgotten, but easily messes up your
descent planning is the wind. Now, in our example we have a
tailwind, which will make it harder for you to lose altitude and kill
speed, so for every 10 knots of wind you add 1 nautical mile, so we have 20 knots divided by 10 equals 2 nautical miles we
have to add to our milage. Now, if it were to be a headwind,
you SUBTRACT the miles. Capisce? So, summing up our calculations, we should
be starting our descent at 104 track miles. As you are in descent, you
want to check every 10,000 feet if you’re still on the
correct vertical profile, and then decrease or increase
your vertical speed. Speaking of vertical speed, there
is another technique you can apply. Now, we’ll use 200 knots as an average
descent speed, as mentioned previously, so we determine the distance
needed of 104 nautical miles, so if you use your
calculations that say 100 NM, that means you need 30 minutes
for the entire distance. 27,000 feet divided by 30 minutes
equals 900 feet per minute, which should be your
average vertical speed. I’m personally not a vertical speed
flyer, and I’ll tell you why: first of all, 900 ft/min is in
most cases not steep enough for the intitial descent,
and the controller will be fuffing about why you’re
descending at such [a] slow rate. In the rarest cases, the vertical profile
is a 3° glide slope from top to bottom, as it is sheer impossible to maintain that
slope, and reduce speed at the same time. Compare it as if you were coasting
downhill a highway at 60 miles, if you wanted to slow down,
but you couldn’t use the brakes. How would you slow down? The only way you’ll be doing that is
if the highway would become shallower. So, commonly, pilots start up with a
high speed descent at 3° or steeper. Now, just before reaching 10,000
feet, you dial down the speed, the plane pitches upwards,
creating a shallower descent path, equal to 1,000 feet per 5 NM. Now, once you receive for the descent
clearance, you rejoin the 3° angle, equal to 1,000 feet vertically,
needing 3 NM horizontally, maintain 250 knots until
reaching 5,000 feet, dial down the speed even more so
you can extend the slats and flaps to establish yourself on the
ILS, VOR approach, etc., so your vertical profile is going
to look something similar to this. Now once established on the
approach, another thumb rule – ground speed times 5 gives you the
necessary vertical speed feet per minute you want to be flying to
maintain on the 3° glideslope. But for the descent I primarily use the
first three thumb rules I’ve mentioned, and your goal should be, as it is mine, to fly the entire
descent on idle power and ONLY apply thrust after
the final flap setting. The least efficient thing you can do is if
you use the speed brakes for the descent and then you have to apply thrust to maintain
altitude before reaching the glideslope. You’ve then killed kinetic
energy for no good reason. That’s the point I’m at right now
with the Queen [Boeing 747], so she’s still testing me, but
I have to admit that sometimes we land with the maximum landing weight and
the next day we land with 100 tonnes less. And that for sure has an impact on the handling
and descent characteristics of the plane. Let’s look at a scenario
which is quite common: the controller won’t give you the
descent clearance due to traffic crossing at lower levels. So you slowly get over
your descent profile. Now what? Now, there are three things you
can do to rejoin your profile once you have your descent clearance: increase speed and indle power; dial up the speed and pull
back the thrust levers and the autopilot immediately will try to capture the speed, but without thrust, and the only way of doing this is by pitching down, so you and your passangers will feel that
descent, believe me, but it’s fun though. Try to get below your descent
profile as quickly as possible, as that will give you space and time
to slow down the airplane again. Now, if ATC advises you to
maintain a certain speed, which is too slow to kill altitude, use your speed brakes – the airbrakes, the high drag devices – whatever
the manufacturer named them, that’s what they are made for. A video about that topic is coming up soon. Now remember the car
scenario mentioned before. Now, you’re allowed to use the
breaks actually to slow down. Now, you might even use the gear or flaps, but you’re most likely not gonna
retract them once you’ve used them. And the last resort, ask for delay
vectors or more track miles. You ever so often hear
collegues ask the controller: “How many track miles can we expect?”, and will response, let’s say, “25 nautical miles”, the pilots quickly do their
calculations, and if they’re too high, they’ll say
“Unable, request delay vectors”. So the controller will extend their downwind,
for example, to give them more time to lose altitude or reduce speed. Now, you might say: “Joe, this is all nice to know, but I’d rather
rely on the data I’ve put into the FMGS, or FMS, and I use all the help given
on the navigation display.” That’s fine by me, but the FMS and
all the other help cannot anticipate a sudden direct approach given by the
controller, and if you’re replying “Unable, we’re too high for the approach.”, you’ll be the reason for many smiley
faces in surrounding cockpits, and they’ll be happy to nick
your slot for the approach, so fly conservatice, but also plan ahead, constantly monitor your distance
to the airport and, if necessary, use the speed brakes or extend
the flaps, or even the gear, to lose speed and altitude. As always, situational awareness is KEY! You’ll get a feel for it, don’t worry. Also, on how to anticipate
the surrounding traffic and the mood of the air traffic controller. A go-around [be]cause you’re
hot and high might happen as you’re unable to establish
yourself on the approach, but it’s not a failure. It’s more of a lesson
that you’ll profit from. That’s it for today, thank
you very much for your time! To become my wingman, hit that subscribe
button and that notificaiton bell, so you won’t miss out upcoming videos. And don’t forget, a good
pilot is always learning! See you next week, all the best, your Captain Joe! [Outro] [Outro]
[English subtitles transcribed by Iliyan Angelov]

 

98 Responses

  1. Daniel Aviation Ireland

    July 29, 2019 1:28 am

    I was on a flight in 2016 when we must’ve got over the descent profile and we could feel it and it wasn’t fun , my ears were in awful pain😂😂😂

    Reply
  2. HYMNS OF PRAISE

    July 30, 2019 1:24 am

    Captain Joe..after listening to all you had to say about this subject, even though you lost me with all those calculations and configurations..(my brain could not handle it), I nevertheless learned one fact. Piloting an aircraft requires a tremendous amount of knowledge, intelligence, skill and courage. None of which I have. Taking on the awesome responsibility of ensuring your passengers arrive at their destinations safely, there is no question that whatever pay pilots of your caliber receive, it is not enough. Just saying.

    Reply
  3. Mark Joel V

    August 3, 2019 12:52 pm

    Thank God I’m not a pilot 👨‍✈️ I will crash the airplane ✈️ because I’m not good with calculations. Good video.

    Reply
  4. Profelis

    August 10, 2019 12:02 am

    Can you tell all this the pilots of Air Botswana please? Ever time I've flown with them the landing is so steep that without seat belts you'd slide out of your seat. Not to mention the door to the cockpit which always flies open – lock, what lock?!? This then means you can see the ground approaching straight ahead!! 😂😱😂😱

    Reply
  5. william herron

    August 10, 2019 8:32 am

    Does a pilot have a different type of passport or do they just have to keep getting new ones due to running out of stamp space

    Reply
  6. tjoo trolo

    August 11, 2019 3:27 am

    I managed to decend with flying piano. Without ILS – and not a single string went out of tune. Now redo that Captain Joe. 3:P

    Reply
  7. Chad Portenga

    August 12, 2019 5:13 pm

    If your girlfriend finds out about the transition to the ex's, you'll probably be diverted to a new destination!

    Reply
  8. Jo Ll

    August 13, 2019 5:54 am

    They don't just turn you loose on your own. Another pilot whose made the trip many times in type aircraft instructs every move you make.

    Reply
  9. Dennis Flo

    August 13, 2019 4:52 pm

    I work in information technology I understand the math and technical part a bit but the actual controls not so much.

    Anyone who think this is complicated you will practice this 10k times in simulators before being in an actual plane so no worries 😉

    Reply
  10. Crystal Lightman

    August 13, 2019 6:18 pm

    You may be a plane expert but let me tell you what to tell the current girlfriend about your 1 hour ex-delay and keep you away from the storm and lightning strikes… First your ex will become Harry, he's a friend's friend and you borrowed a power drill from him, that he desperately needs back tonight, without delay, because he needs it to finish up his kitchen counter tonight, because he has family coming over tomorrow, that Harry hasn't seen in 8 years, and he's finishing it up tonight! Once over at Harry's, make a quick call to your gf, from the driveway) and say these exact words… Honey, I'll be about an hour or so because you're going to give Harry a quick hand with his kitchen small job! (don't forget to say the word so, because it automatically buys you another 45 minutes on top of the hour delay!). And take it from here… its an extensively lengthy manual, once you've mastered it you will have earned your wings and have kept the frying pan away from your heading!

    Reply
  11. badlongon

    August 14, 2019 4:44 am

    That girlfriend and ex-girlfriend example cracked me up. Hahaha. Must have happened to you, I guess?? Hahaha

    Reply
  12. Douglas Nisbet

    August 14, 2019 11:15 am

    Typical instagram pilot trying to make things out to be more complex. In a typical Boeing FMC you input descent forecast winds, ISA deviation and approach speed limit points. The FMC calculates and extremely precise descent point for a perfect CDA. This idiot just seriously enjoys the sound of his own voice.

    Reply
  13. Douglas Nisbet

    August 14, 2019 11:42 am

    The FMC definitely CAN anticipate a shorter approach. This idiot is such a wet blanket. He is giving out false information and trying to make himself look smart.

    Reply
  14. keri caye

    August 18, 2019 8:50 pm

    I wish I was young enough to be YOURS……………………hmmmmmm to cute for words Captain of my heart

    Reply
  15. heavy meddle

    August 21, 2019 10:43 am

    Its not as hard as it seems. He's just a windbag. Its not very different from parking a helicopter. This plane driver is just an illuminati shill from NASA payed by Rockefeller and his friends

    Reply
  16. The Suicidal Plain Yogurt

    August 22, 2019 9:31 pm

    doesnt flight control measure some stuff with some information provided by you and then tell you to bring it lower and lower and then bring it down when everything is at the right measurements?

    Reply
  17. nathan adekoya

    August 23, 2019 10:27 pm

    how do I become an airline pilot after high school do I go to the military or what
    does pilot go to college?

    I want to be an airline pilot when I grow up

    Reply
  18. saner sabahci

    August 27, 2019 6:35 pm

    I am an air traffic controller working at ACC departmant.

    (ANKARA (City)/TURKEY)
    thanx for video Joe 😊👍🏻

    Reply
  19. Aviation 777

    August 28, 2019 7:22 am

    If your girlfriend wants you to call 30 miles prior to arriving at her house then she's probably cheating on you. Lmao

    Reply
  20. Mr Dub Crazy

    August 29, 2019 7:11 pm

    My girlfriend is cooking from the day before. Bulgarian cuisine ain't no microwave boil in the bag shit! Poor westerner fellas.

    Reply
  21. Tomasee Ah

    August 31, 2019 7:45 am

    How does a pilot know when to decent?

    Math. Shit tons of math. Math here math there math everywhere. Touch down!

    Reply
  22. C-130 Hercules

    August 31, 2019 10:41 am

    Im still on high school 2nd year and on school days I study the lessons while on weekends I study aviation like how to takeoff a plane,descend etc…. so that I could be ahead of my classmates and friends!

    Reply
  23. Goldman

    September 1, 2019 11:32 am

    Wow thanks captain it was a very good explanations Please we need more details and examples for the next videos at the same subject. And how to use this a miss for T/ D performance

    Reply
  24. FlyJV

    September 2, 2019 11:05 am

    Great Video, an easier to calculate V/S on 3deg Glide is to take GS and simply divide by 2 and add a zero. So in your example: 147÷2=75 add a zero and we have 750fpm

    Reply
  25. Jesus Antonio

    September 3, 2019 8:49 am

    This is something cool that I figured out on a video game not too long ago, I'd use time to arrival multiplied by decent rate to get distance. As in descent from FL413 at 2,000 fpm decent I'd need 20m. Usually at Mach .8 would be 120 miles out. Once at 10,000 follow approach level off at 2,000 feet AGL on the ILS or on the visual. Credits to Infinite Flight!

    Reply
  26. Dave William

    September 3, 2019 11:48 pm

    Very nice video. 3 Times the altitude to lose plus 10 miles for slowing to 250 knots by 10000 works on for most medium jet aircraft. I check the altitude when doing that, and adjust speed slightly to compensate for a diverging profile. Slightly high, increase speed 10 knots, slightly low, decrease speed 10 knots. ATC often has other plans though flying around the busy USA Northeast/Midwest/SE Florida. Florida area, they get you down way too early, but as most their traffic funnels through the southern pan-handle, I can see why they have do this. Yes weight and wind are factors, but a good general way to cross check what the FMS(G) is doing is a quick math check to the nearest downrange along track descent waypoint as per above.

    Reply
  27. hhhm.1

    September 5, 2019 12:56 am

    Either you could search it up on google or look for answers on joe’s channel. We’re all here for a reason 👍👨🏻‍✈️

    Reply
  28. Equal Vector

    September 9, 2019 3:37 pm

    You didn't mention the holding pattern. Isn't that a way to achieve your descend or it is only if there is another approach by another airplane or bad weather or something else?

    Reply
  29. Manrique Hidalgo

    September 13, 2019 3:00 am

    My dear friend
    Yes and No.
    Agree alitude to lose divide by 3, excelent that give distance.
    But the Time you Descent, now you multiplying the distance x 3.
    For example if going to SL and you are 79:miles out 70x 3 21 si you ve 21000, and un this case SL, but if not add Airport Elevation
    To decelerate 10 knots we need 1 nautical mile at power in idle and level flight.
    for the wind Remember that it is the ground speed between 2, for example 400 Kts G / S would be a descent regime of 200 we add a 0 and we have 2000 feet x minute, now if we find tail wind of for example 40 Kts then we now have 440kts of G / S then 440: divided by 2: it is 220 masvun 0 now we have 2200 feet per minute. and guess how that corrects the A320 with the bracket in the speed so Is why it exists. I hope you have understood me.
    I prove this from DC 3, DC6, 727,737, E190 yo A320:and general aviation

    Reply
  30. Terry Anderson

    September 15, 2019 9:33 pm

    A pilot knows when to descend when there is too much air in the tanks or you’re on fire (seriously though thanks Joe for your insights)

    Reply
  31. owllettefluff

    September 17, 2019 10:28 am

    Hi Captain Joe, can you do a vid on coms between the control tower and pilots ? how do you coms with different accent ? how do copy that from each nationality ? thanks C. Joe

    Reply
  32. Miguel Angel

    September 18, 2019 3:46 am

    Sounds like a lot of stuff but how do they do it in the movies when the pilots are dead and a passenger is assisted from ground to land the plane?

    Reply
  33. Airash Samuel Kiran

    September 21, 2019 7:44 pm

    Dubai Dxb to Pakistan Multan mux only 2 hour 30 minutes but MUX to DXB 2 hour 45 or 50 or 55 way like this

    Reply
  34. Allen Richards

    September 21, 2019 10:39 pm

    After seeing 9:14, I remembered that I used to wonder how planes avoided crashing into each other when there was so much air traffic and so many planes flying in different directions. I knew they have the radar, but I wondered how does even that keep all the different planes aligned and flying in such a way to where they could all avoid a situation where one wouldn't have enough time to dodge out of the way of another. Got to remember that these planes are all flying somewhere between 200 and 500 mph (depending on how high up they are)

    Reply
  35. Shirley Reece

    September 25, 2019 3:45 pm

    It's a shame everybody's worried about the the girlfriend and no one is interesting in the information you just gave them that is very important I see why they all watching YouTube at home and none of them have commercial pilot license it shows how dumb people can be when you putting out educational information for freeI wish you had a school out here in the US I will definitely attend the school Captain Joe keep up the good work keep your head high and fly to the sky good work you are very good teacher

    Reply
  36. Christian De Leo

    September 29, 2019 11:18 pm

    Vertical take off for airlines?? Is it true or even possible?
    Recently I saw a couple of YouTube videos where airlines almost did a vertical take off but I am suspicious.. would vertical take off slow down the airplane too much or the jet engines would be able to cooperate and continue to give enough power?
    Thank you,
    Chris

    Reply
  37. BrutusPalmeira

    September 30, 2019 5:17 pm

    Yeah, if your girlfriend asks you to call 30 miles before getting to her apartment, you know it's time to call your trusty ex-girlfriend and remanence.

    Reply

Leave a Reply