Use of speed brakes in flight

[colsie]

Hello all. I think this might be my first post here.

So a tiny bit about me first of all. I am called Colin. I am 15 live in Glasgow, Scotland. And love planes.

I have a question regarding the use of speed brakes in flight and on approach.

What are the real life limitations apart from speed for not using speed brake in flight?

Is there any point in which it is forbidden as so to speak to release and use the spoiler in flight?

Is it really advisable to use speed brakes in flight unless it is absolutely necessary?

Thanks,
Colin

[greenslopes]

G'day Col,

Different aircraft have different limitations. I can't think of one right now which requires you to be below a certain speed in ordr to use. The speedbrake is there so if you reach the high speed limit(Mmo) you can pop them out and slow down............hence "speed brakes", they also help you increase the drag in the L/D equation thus increasing the descent profile(particularly useful with say a depressurisation or uncontained cabin fire). Some aircraft require they not be deployed when flaps are set greater than ten degrees and many operators do not allow them to be used below 1000 ft(as standard operating procedure rather than an airframe limitation).
Hope this helps

[colsie]

Thank you very much. That has answered my question fairly well.

If anyone has any specifics on the 767 I would be overjoyed however.

Thanks,
Colin.

[FlexibleResponse]

And they are also used for landing (or rejected take-off) to decrease lift on the wing and therefore increase weight on the wheels to make the wheel braking system more effective.

[Dont Hang Up]

One regularly hears the terms "speed brakes", "spoilers", and "lift dumpers" and I am never really sure if these are all different things or fundamentally the same. I used to fly a (light) aircraft that had airbrakes on the underside of the wing. I'm guessing that's not the case on a commercial jets though.

[FE Hoppy]

Technically speaking the panels on top of the wing on most if not all modern jets are "spoilers". They are used for various functions such as:

"Speed Brake" - symmetrical variable deployment of some or all pairs of spoilers to increase drag and reduce lift. Often the most inboard pairs are not used for this function.

"Ground Spoiler" - sometimes called Lift Dump - symmetrical deployment of all pairs to max position in order to disrupt lift and put the weight on the wheels to improve braking on landing or in the case of a rejected take off.


"Roll spoiler" - Asymmetric variable deployment to assist or completely control roll.

"Direct Lift Control" - Symmetrical variable deployment coupled to elevator or stabilizer input in order to "Directly control the lift" as apposed to indirect lift control by virtue of varying pitch and therefore AOA.

"Maneuver Direct Lift Control" - symmetrical automatic variable deployment of some or all pairs in order to reduce load factor during high speed maneuvers.

Did I miss any?

[canyonblue737]

In general for most airplanes their speed brakes are useable at any speed. The 737 does have a limitation at most carriers preventing speed brake use with flaps at the same time.

[colsie]

I want to thank you all for these answers.

Especially FE Hoppy I have now learned a lot I never knew about the wing.

[kijangnim]

Hi cosie
the speed brakes are the only fly by wire on the B767, when you pull the handle out of its detent, the speed brakes will pop up and create a slight a short pitching moment, and it takes a little bit of practice to master.
Once I had to diverte (due to a pax weird behavior), the weight was above max landing weight and no jetisson, I cruised with speed brakes slightly out to increase the drag,thus the fuel flow, without compromising the speed. I landed at the max landing weight.
regards

[Rainboe]

Colsie, there are other factors of interest. Speedbrake causes vibration throughout the aeroplane. With flaps extended it gets worse. It can be quite sobering to sit behind the wing and see what speedbrake does to the flaps. That is the reason the use of speedbrake is not recommended beyond a certain level of flap. Flap 5 on the 737 and full speedbrake is not a nice combination!

Another reason is that you are throwing away efficiency, and I view it as an admission that you have misjudged the descent if you need to use speedbrake except where you are having to obey ATC instructions. If you have free reign over your descent and use speedbrake, you are throwing away energy, hence you have wasted fuel. It comes with practice!

Another factor may interest you- using partial speedbrake on the 737 is not recommended because it affects the roll control and makes the aileron control more sensitive. However I don't like using full speedbrake, especially when any flap is out, so I only use what I need and take care with very gentle controls.

Right- are you ready for your exam?

(May I say how nice to see such a well phrased query? You are very welcome to ask more! Do you have a further interest in aviation?)

[411A]

FE Hoppy has given you superb information, Colin, but he forget to mention one rather important item...

"Direct Lift Control" - Symmetrical variable deployment coupled to elevator or stabilizer input in order to "Directly control the lift" as apposed to indirect lift control by virtue of varying pitch and therefore AOA.

"Maneuver Direct Lift Control" - symmetrical automatic variable deployment of some or all pairs in order to reduce load factor during high speed maneuvers.


These functions of the spoilers are found only on one type of civil jet transport. And, they are fully automatic, requiring no separate pilot action.
It was manufactured by the Lockheed California Company at Palmdale California, and is called...the Lockheed L-1011 TriStar.




Sorry folks...but it's true.
Lockheed...far far ahead of everyone else, at the time.

[colsie]

Again I would like to thank you all for these very informative and most importantly educational answers.

Rainboe my main interest in aviation is with the good old (well modern actually), airbus aircraft. I do however like the Boeing 767's and 727's. Actually anything which is vintage is a big go in my book.

Unfortunately any career in the skies is out of my reach, this due to my poor eye sight. So I need to suffice and aim for a job in the airport.

It is nice to be welcomed into such as good community. I hope you look forward to more of my questions.

Thanks,
Colin

[World of Tweed]

Colin,

As you ask about the 767:

There is no limitation on its use in terms of speed. Part of the drill for an overspeed condition is t deploy speed brakes first before retarding the thrust levers. This does two things, one increase drag and two cause the nose to pitch up as the centre of pressure (the point through which lift acts) moves. Nose goes up, reducing speed rapidly.

Company SOP is no speedbrake use beyond Flap 20.

On the 757s we have fitted with winglets there is a limitation on full speed brake deployment - 330 Knots Indicated Airspeed. Maximum of 50% deployment only is permitted beyond this speed. There is an auto stow facility which limits the spoiler movement above this speed. This limit is to do with the bending of the wing caused by the winglets combined with the loss of lift at the root of the wing at such high speeds. Winglets place a greater bending force on the outer portion of the wing upward than on aircraft without therefore when you deploy the spoilers at the centre of the wing you effectively increase this bending force placing extra stress on the structure. This is not desirable at such speeds.

The speedbrakes on the 757 are not that effective at low speeds with the aircraft being so overpowered. At lower speeds 220kts or so it is little more than a rumble maker.

[Rainboe]

Yes it is! Unnecessary use of the speedbrake and I throw a tantrum! Waving a rolled-up newspaper around and shouting 'you're wasting my fuel! Have you ever REALLY been short of fuel in your miserable short existence?' sort of question. Far too many young pilots use speedbrake almost every flight- it's almost a dummy for them, and they'll use it happily knowing that they will probably have to fly level later, but such is their horror of being high they overuse it badly. 200 up to MCT is an ATC requirement- it is using it when planning and foresight would have prevented it that annoys me. I used to fly 747s. The potential to really waste a large amount of fuel through poor planning instilled discipline!

Colsie- good luck with your eventual entry into aviation. You have a very good understanding from your question. Airbus needs you! Work hard.

[colsie]

Again I would like to say thank you all for the replies. And now the interesting informative following discussion.

Oh and Rainboe as for Airbus needing me, Airbus need anything.

[Desk Jockey]

Colsie-I'd recommend you read "Handling the big jets" by D P Davies. Published by the Civil Aviation Authority. Don't know if it is still in print but your library or Amazon should have one.

[colsie]

Thank you for that advice. I shall look into this book.

[Dont Hang Up]

Reminds me of the story (possible read somewhere on PPrune) of the pilot who is being nagged repeatedly to expedite descent by ATC. "Don't you have speed brakes?" says the ATCO with exasperation. "Yes" comes the reply "But those are for my mistakes not yours."

[john_tullamarine]

.. hence PECL .. pilot error correction lever ....

[FE Hoppy]

411A.

Not entirely true anymore.

The little E-jet 170 uses DLC for steep approach. More for drag than lift control but it works in exactly the same way.

:-)

[colsie]

john_tullamarine, congratulations you have made me laugh. :eek:

That at least explains it's use on some airline's were the pilots have flown less than competently.

[RWEDAREYET]

Colin,As stated earlier, the primary reason for lift dumping is to get down in a hurry. During the certification process, transport category aircraft must be able to get down from max operating altitude to 10000 ft in a predicated amount of time. Can't remember the exact time, but if I recall correctly, there are two segments, first to FL250 and then to 10000ft. The DC-8 does not have "speed brakes" only ground spoilers, so to get down in a hurry, you need to use reverse thrust. The first time you see, feel and hear it, it definetly gets your attention.

[colsie]

Hopefully I will never feel nor hear that occurring inflight. Does not sound an enjoyable prospect.

If any pilot is interested it was an approach into Zante which I experienced for the first time the use of speed brake's in flight. However the pilot was using them for about 30 seconds then taking them away again. Waiting a couple of minutes deploying them again, to them stow after about 30 seconds.

Sorry if this lacks terminology.

[Wizofoz]

That at least explains it's use on some airline's were the pilots have flown less than competently.

Rainboe,

Congratulations! You've managed to convince a young enthusiast that if he ever sees the SB used, it's because of pilot incompetence!!!!

In a perfect world, descent without recourse to the boards is great. In the real world, any number of unforeseen things can happen, and use of the brakes should not be discouraged. It's a flight control. It should be used as necessary.

I used to fly with a guy who was so caught with the "Brake up = F@@@ up" mentality that he would fly extra track miles rather than use the brakes, somehow believing that was more efficient.

After TOD, getting the aircraft on the ground as soon as possible is the most efficient thing to do. If circumstance leads to being high or fast, the Speed Brake is that most expeditious way to correct that. The MOST important thing is to achieve a stabilized approach, and attitudes that preclude using available controls to achieve that are dangerous.

[bubbers44]

Speed brakes in flight normally are used with late descent clearances or late runway changes making a circling approach a straight in approach. They get used a lot if a pilot just gets too high on approach. They vibrate, depending on speed and flap setting, so are not comfortable for passengers. I try never to use them but sometimes you must.

[Stan Woolley]

Wizofoz
+1

[scudbus258]

I fly A319/20/21's, only use Speed brakes regularly on the 319's as at certain weights it can sometimes be tricky to keep 160kts till 4d in flap 2. A trickle of speed break is better than using the gear as then you have an excess of drag and the power comes on. Better to be at idle all the way and then configure to be in the groove spooled up by 1000', checks complete and all above board. So there is nothing wrong with using a bit of speed break, but at the same time as most will say 3 times table works well for decent profile management and then plus 5-10 miles for slow down. But we're bombing around at cost index 10 at the mo so no need for extra to slow down, can't get much slower!

[Rainboe]

Congratulations! You've managed to convince a young enthusiast that if he ever sees the SB used, it's because of pilot incompetence!!!!
Blubber's got it right. I stressed that it was pilot incompetence or ATC requirements! I get into a sulk not because SB is used, but the descent was misflown to get into that situation. A second major error is to overuse SB 'just in case' knowing level flight will be needed with power later on. Some pilots don't realise that although it doesn't inherently use fuel itself, it causes extra fuel to be used at some stage. So it is an admission that 'I am a little not up to my descent planning!' The whole idea is stretching your glide out as long as possible and being a fuel miser....which is what I am, out of duty to my employer's bottom line, and not being wasteful.

Colsie, going into the Greek Islands is not only wonderfully scenic, but rapid descents are needed requiring SB several times. You came over Kephallonia which has an airport of its own and BIG mountains, so that was the need for the SB.

[colsie]

Bubbers44, what you have said may have been what occurred coming into Zante. Maybe it is me and just being used to standard approaches, I think the only other approach like that I have been on board the aircraft is going into Faro.

Coming into Zante we had a strong crosswind and it appeared to be a hot and high approach 9I think that is what it is called), the pilot made several circling movements, which i thought was the holding pattern onto the runway.

Oh and rainbow has not convinvced me this. Just my expeirence with planes has been limited to flying on a 734 globepsan, 3x753 thomas cook and A321 First choice. And when I was younger I flew a couple of BA 757's. On each of those flights the pilots have been much more talkative to the cabin,a nd going over what ahs occured (well not in the globespan and some Thomas cook flight's). Oh i probbaly should not be mentioning the airline names, sorry if I am not meant to.

[Wizofoz]

RB,

Fair enough if you get it just right every time, but you are expecting your less experienced FO to be as good as you, whilst letting him know he'll get what-for if he doesn't measure up.

One go-around because he gets it wrong negates all the fuel savings you desire for a couple of years. One "Press-on" hot/high approach is potentially much worse!!

Given the choice between going for the ragged edge of efficiency or being a little conservative, I'll "Waist" the 15kg of fuel to ensure a safe outcome.

[Rainboe]

Sorry, but you're still not seeing the point! The aim is to avoid getting into the situation of using SB to begin with, not just not using them when needed. I sometimes make full and free use of them myself, but not when I could have avoided it altogether. Besides, their effectivenss below 250kts is limited. There is no arguing with dropping the gear early and sticking the nose down for that final rapid descent rather than poncing around with limited use speedbrake. The Malaga approach is the example.

[Wizofoz]

Agreed RB, I just a little techy when people start talking about rolled up newspapers as CRM tools!!

A previous generation of Captains used to be very anal about the SB, with some justification as, has been pointed out, some early jets either prohibited their use or had nasty vibrations with them out. This often led to a certain "Intake of breath and roll of eyeballs" mentality whenever they were used, whether the result of a planning error or external factors, and I remember more than once a guy pushing a bad situation rather than simply chuching out the boards and getting back on glide.

So certainly, plan for the best and adapt to what happens, I'm just content to do so on the conservative side.

Perhaps a quiet word rather than sulking and swatting might be more PC in this day and age?

[763 jock]

Nothing better than chucking out the speedbrakes at 340 knots in order to have a go at an unexpected straight in. They can be an excellent time saving device on occasions!:}

[411A]

Nothing better than chucking out the speedbrakes at 340 knots in order to have a go at an unexpected straight in. They can be an excellent time saving device on occasions!

Yes, however you had better have your act together, otherwise there might be the unfortunate possibility that the outcome may well not be to your liking...as in, American Airlines at Cali, Colombia, some years ago.

About two years ago I was flying with a quite junior guy, and he was offered a hurried straight in...he looks at me and says...'what do you think?
I mention...'what do you think as you're flying?'
He declines the hurried straight-in approach...smart fellow.

[Junkflyer]

The company limitation for our 767-300ER aircraft is "do not land with speedbrakes deployed" We will get a warning light and beeper if the speedbrakes are deployed below 800 feet or with landing flaps down.

[Mac the Knife]

"If you have free reign over your descent......"

Should be "free rein" Rainboe

The reference is to equitation rather than empires

Ahem....

:ok:

[411A]

411A.

Not entirely true anymore.

The little E-jet 170 uses DLC for steep approach. More for drag than lift control but it works in exactly the same way.


Gosh, didn't know.
Considering...it took 'em twenty five years to 'catch up'...good for them!
Lockheed was so far ahead of everyone else, without exception.
Fact.


Must add, with proper Rollers, of course.

RollsRoyce, the absolute best turbine engines going...fact.
Proven time and time ....again.

[Rainboe]

Should be "free rein" Rainboe/ The reference is to equitation rather than empires
Of course. I shouldn't of done that! Are we learning Pruners?

[Justin Cyder-Belvoir]

And then some aircraft land with the speedbrake deployed.

Vulcan, RJs, Fokker 100 / 70, Buccaneer to name but a few.

Use of speedbrake reduces the minimum drag speed on approach, the engines have to be at a higher thrust setting which improves response in the event of a go around.

[dany4kin]

To quote RB, "Of course. I shouldn't of done that! Are we learning Pruners? "

Shouldn't that be shouldn't have done that?

:O

[Rainboe]

Top marks that man! I did it on purpose and made the mistake intentionally out of respect for the many Ppruners here who appear to think that is the way what it is done! I italicised it to give a clue, but it seems to be what they teach in schools these days!

[dany4kin]

Ah I thought as much!

:)

[411A]

Not mentioned so far (unless I missed it) is the use of split spoilers for pitch control in the event of stab problems...jammed in the cruise position, for example.
Personally used this twice on the 'ole 707...very handy to have this facility, so you don't have to strong-arm the pole...or even worse, run out of elevator authority.
Or, on takeoff.
DAL had quite a nasty incident with one of their L1011's, when the elevators remained in the full nose-up position after the normal control check (elevators mechanically linked to the all-flying stab) at KSAN.
So, split the spoilers (all off except 1&2 inboard panels), then use the spoiler lever to get the nose down.
Very handy, indeed.

[Antunes]

Hello Colin

Seems that you like Airbus aircraft, so here are some interesting facts related to speebrake use in the A320 family.

*(A320) With autopilot on, the maximum deflection will be achieved when you put the speedbrake lever at the "1/2" position. Even if the lever is at the "Full", the system won't allow you go further than half. :ugh:
Although you have limited authority, it's just fine for most STAR's and ATC requests.
For full speedbrake deflection, you'll need to disconnect the autopilot.

*Speedbrake will retract automatically if one of the below conditions occur:
1- Flaps at FULL (3 and FULL for the A321)
2- Thrust levers above the MCT detent
3- Alpha Floor activation
4- Angle of Attack protection active (...and much more!)

This is extremely useful in a GPWS "Pull Up" call, for example. When you apply TOGA, the speedbrake will retract (although the memory item asks for you to check the speedbrake lever in the retracted position!)

Hope you enjoy it :ok:

[colsie]

I would again like to thank you very much.

Antunes I liked you're rather informative and educating reply. May I ask however what is Alpha Floor activation?

Thank you
Colin.

[Lafyar Cokov]

Just to momentarily go back to the original question (by the way - I have never used speed brakes, reverse thrust or wheel brakes - it all stinks of poor energy management to me!!) - Long ago when I flew the Tucano, some airframes did have a 250kt restriction on the 'air-brake' (as it was called then!) and with a Vne of 300kts it always seemed quite strange that you had to wait to slow down to be able to use speed brake. I believe this was a structural limit on the actuator mechanism which was straining and bending under the hgh loading at faster speeds. In time they were upgraded and I think that they now all have a 300kt limit.

[SOPS]

I really hope you are not "waving your rolled up newspaper about" and "putting the gear down for a final plunge" all at the same time...it could all get rather messy. Sorry, I come from the..if you need 'em use'em school, thats why they are there. And its better to be a little low early and stabalised, than high and fast......

standing by for incoming.....

[haughtney1]

If you need 'em use 'em, and those of us who fly into the good Ole US of A need them an awful lot:D

Those old salty dogs in the left seat who advocate a rolled up newspaper...would get from me, a nice short left jab in return...:ouch:

[Vic777]

The only time you use "speed brakes" is in flight.
When used on the ground they are called "spoilers"

(I'm just messin with your mind)

[40&80]

Whilst I read the Airbus will auto stow the speedbrakes with thrust above MCT.
I believe the B767 will not...
Because of the potential danger of reduced climb performance caused by this design feature in an attempted goard or pull up manouver requireing full power... the Gf SOPs for the 767 in my day required the handling pilot to always keep his hand attached to the speedbrake lever if he was useing speedbrake until he restowed the speedbrake lever totally... then he could let go of it. Partial speed brake was not to be used...smoothly use the lot or not at all..was also GF SOP.
The general idea was I believe to avoid the full application of thrust ever being used with the speedbrakes deployed fully or even partially with a steep climb being wanted...i.e. You were never to forget speedbrakes were deployed and would not auto restow.
I think the AA pilots B767 at Cali unfortunately ended up in this undesireable configuration...after being offered and deciding to accept the ATC option to change their minds to a shortend track miles to touchdown straight in approach...they had previously planned and briefed for a more gentle overhead procedure as published on the approach plate.
Probably they thought they had a valid reason to brief for one approach and then attempt another at short notice....they fully deployed the speedbrakes to increase the aircraft rate of descent at night into a high terrain area to try and achieve this new approach descent profile and it appears they left the speedbrakes deployed until they crashed... they were also not really sure of their exact position when asked by ATC... later attempting an escape manouvre they hit the hills I believe with power fully on..nose pitched up...speedbrakes fully deployed..then their luck ran out.
Regarding L1011 DLC....I was told DLC had to be fitted because it was desireable the aircraft retained the Glideslope with a constant pitch attitude and provided a consistant pilot runway picture on a visual approach and a constant point of reference when looking for the runway in LVP.
If I remember correctly there was a required pilots seat back angle and position on landings and also a pilot eye locater devise to ensure a consistant view to both pilots...it also helped them to reach nearly all of the knobs and switches they might need.
DLC was also required to ensure the L1011 would land within the limits require for auto land certification at the correct autoland runway touchdown point.
Monitoring and ensuring the correct ADI pitch attitude on the glidescope was important to L1011 pilots.
On an autoland approach an Auto throttle drive failure was not announced as a failure to the pilots or flight engineer... and had to be picked up by crew monitoring.
With an Auto throttle drive failure the glide slope was retained by the coupled auto pilot and the pitch attitude would slowly and silently increase and the IAS would slowly then not so slowly bleed off...if this situation was not noticed and immediatly corrected with positive manual power application and the correct pitch attitude and speed regained or a goard performed you would next see an alpha flag and next a stall warning which might wake you up...if not Gf SOP was... the flight engineer gave you full power... the f/o pressed toga and manually flew the aircraft to a safe MSA..
In this situation GF SOPS (as ammended) required the flight service supervisor (female if you were lucky) to immediately enter the cockpit useing her axcess key... and bite the end off the Captains cock...and to inform the Captain that this service was on behalf of GF ops. management for being such a piss poor Captain..... National Captains as you would expect got a blow job... and a promotion for handling the situation so well.
A L1011 manual or autoland landing attempt with a pitch up attitude of I believe more than 11degrees was likely to result in an expensive tail strike
and a revisit from the flight service supervisor.

[411A]

Regarding L1011 DLC....I was told DLC had to be fitted because it was desireable the aircraft retained the Glideslope with a constant pitch attitude and provided a consistant pilot runway picture on a visual approach and a constant point of reference when looking for the runway in LVP.
If I remember correctly there was a required pilots seat back angle and position on landings and also a pilot eye locater devise to ensure a consistant view to both pilots...it also helped them to reach nearly all of the knobs and switches they might need.
DLC was also required to ensure the L1011 would land within the limits require for auto land certification at the correct autoland runway touchdown point.
Monitoring and ensuring the correct ADI pitch attitude on the glidescope was important to L1011 pilots.
On an autoland approach an Auto throttle drive failure was not announced as a failure to the pilots or flight engineer... and had to picked up by crew monitoring.
With an Auto throttle drive failure the glide slope was retained by the coupled auto pilot and the pitch attitude would slowly and silently increase and the IAS would slowly then not so slowly bleed off...in this situation was not noticed and immediatly corrected with positive manual power application and the correct pitch attitude and speed regained or a goard performed you would next an alpha flag and next a stall warning...a manual or autoland landing attempt with a pitch up attitude of I believe more than 11degrees was likely to result in an expensive tail strike.
I last flew the L1011 in Jan 1989 so all I say is probably all full of **** as my memory is nearly time ex.


Nothing wrong with your memory...all generally correct.
DLC enabled the L1011 to be CATIIIB certified, right out of the factory...not done later, as with other earlier designs.

However, it was always amusing to watch a new TriStar pilot attempt the 'Boeing push' for an extra smooth landing.
Ha!
The resulting thud would knock you back teeth loose...good thing Lockheed bolted the wings on really tight for these ex-Boeing guys.:}

[Capt Snooze]

RB

and being a fuel miser....which is what I am, out of duty to my employer's bottom line..........................Bit of a fuel miser myself, but out of pure self interest, not a sense of company loyalty.

When I execute the missed approach, I want the maximum available fuel for the hold / divert. :ok:

Can never understand the guys that are lazy about saving fuel, because 'the company doesn't give a sh&t about me"! :ugh:

Of course, if it helps the company survive through to another pay day, it's a bonus! ;)





Snooze

[cwatters]

Just to add a different twist...

On a glider the Air Brakes fitted to the wing operate slightly differently. They still reduce lift and increase drag but aren't normally used to the control speed or perhaps I should say they aren't directly used to control speed. Typically on approach the speed is set using elevator then the air brake is used to adjust the glide angle.

In an ideal landing the glider would be flown (using good planning) into a position where about half air brake can be used all the way down final. If you find you are using all or none then basically you got it wrong. If you find you need all the brake it means you started too high or over estimated the wind speed - and you risk an overshoot. If you find you need no brake then you were too low or you under estimated the wind - and risk an undershoot.

[groundfloor]

Speedbrake = Capts precision planning device and Co- Pilots bad planning device...:}.

Into London this morning; 25 Nm then 20 Nm to go from ATC then instruction turn left onto base leg - Boss`s name is now "Heinz" as he obviously used to fly Stuka`s! Did he use the speedbrake? You betcha

Used all that other drag stuff as well, wheels flaps etc.....:)

[Fil]

Think it was alluded to earlier in this thread about the A320 series but the 777 is very hard to slow onceon the glideslope and almost always requires speedbrakes to slow 180/160kts etc.

[Agaricus bisporus]

IMHO Rainboe's position on use / misuse of speedbrakes is spot-on.

They are (in my company) used far far too often, and usually unnecessarily/incorrectly. Many pilots use them on every sector, sometimes several times. This is far too often if proper descent planning and judgement are used.

As RB said, use of speedbrake in intermediate descent where a level sector is to follow is usually a sign of incorrect entry point for that descent, and a slight speed adjustment will often sort that out without shaking the airframe and scaring some of the pax with the vibration. It is a much kinder and smoother way to achieve the same thing, but no, most just dive for the mistake handle. Use of speedbrake followed by an increase in power is, as RB said, often a very questionable procedure.

Pavlovian use of sb whenever the indicator says above profile is another common fault. It happens on a daily basis and is almost always unnecessary, and avoidable by a bit of thought of what lies ahead.

They are sometimes used like brakes on a car for speed reductions in level flight! (followed by a power increase, of course...) This is all just evidence of poor planning and awareness.

On the 737 it is virtually useless below 250Kts anyway, and Mr Boeing recommends it is NOT USED in conjunction with flaps. So why use a control that won't help you, that compromises controlability, that stresses the airframe and pax and that the manufacturer recommends you don't use in this scenario when you can put the wheels down a few seconds earlier than usual? "Non standard, gear down" solves the problem, unless you are so stuck in your SOPs that you just can't fly the aeroplane...It also has the advantage that it works, because if significantly high at this stage the sb's extra 200fpm won't help you anyway, and the minute or so it will take to become obvious just brings the aircraft ever higher and closer in, requiring ever more drastic action to correct.

There are many ways to skin a cat, as there are many ways to get an aeroplane to descend faster. Some are neater, more comfortable and more Proessional than others. You don't have to use the sb every time.

A bit of thought would prevent 75% of use of speedbrakes. IMHO, of course!

And finally, if you must use them, for God's sake use them smoothly and gently. They can cause the most sickening lurches when handled clumsily - which happens all too often, sadly. But then all too often pilots seem blissfully unaware that there are pax behind them who are very aware of jerky, uncomfortable flying.

(Same goes for wheel braking, but that is another topic entirely)

[BOAC]

Agreed, AB - I think the only difference you and I have with RB is the use of a rolled-up Daily Mail? I normally gently 'stay' the grabbing hand and say - why? Generally a light then comes on in the head and another way is thought of. There must be some Captains who always grab for the s/b in order to instill such 'automatic' reactions? Could it be as simple as Boeing's message 'Drag required'?

Incidentally, BA (used to, up to 2004 anyway) impose NO limits on s/b with flap on the 737, right up to Flap40:eek:, merely not below 1000'. I have personally experienced it used at Flap30 by a BA 737 captain (only briefly, I should add:)). The biggest structural danger IMO is the tailplane buffet.

[Agaricus bisporus]

BOAC, you are spot-on, as usual.

Use of the Daily mail as described by Rainboe is shameful in this day and age. I am disgusted that there are still Captains around with such appalling CRM as to beat studes with the Mail instead of the Telegraph, which, apart from being factual and useful is also being bigger and heavier and thus so much more effective. The "CRM" displayed by Captains who read the Mail is best left unsaid.

God bless Sqn Ldr Gell RAF who introduced me to this valuable technique, though it could be a trifle disorientating half way around a loop...

[Rainboe]

The use of a rolled up newspaper is excellent for 'imprinting' what one is trying to get over. Indeed, being a former inmate of a boarding school, I positively need this to remember. I even asked my simulator instructor to use just this item on my recent conversion course to the 757 as after enormous years of 747 and 737 and other aeroplanes that refer to engines as 1, 2, 3&4 (I'm showing off with the last group there), I now have to fly a bloody aeroplane that refers to them as 'Left' and 'Right' for some weird reason. I was unable to ditch the habit in an emergency, a swear box fine didn't work, so I requested a rolled up newspaper on the back of the head, just as I was given so much in my youth! It took 10 sessions to sink in.
Quite apart from limited ability descent planning upsetting me, I am REALLY upset at some of the appalling CDAs the young chaps come out with, thinking what a jolly good job they are doing. Flying level over central London at 3000' has me positively turning green with muscles rippling out of my shirt. Then the language comes.........

[BOAC]

being bigger and heavier and thus so much more effective- personally I prefer the FT - the crossword is much 'harder'.

I'll raise your S/L Gell with a billiard cue in the back of the bonedome (Chipmunk):)

[JammedStab]

However, it was always amusing to watch a new TriStar pilot attempt the 'Boeing push' for an extra smooth landing.I've done the push on the 727 quite a bit, was it done on the 707 as well?

[NickNavarro]

Can someone tell me what the Boeing Push is?

[West Coast]

School of thought that says pushing forward in the flare will reduce the mains ROD and roll it on.

[411A]

was it done on the 707 as well?

Yes it was, with good results.

[john_tullamarine]

God bless Sqn Ldr Gell RAF who introduced me to this valuable technique

.. it is comparatively easy to divine those of our PPRuNe band who learnt to fly more than a few decades ago ..... for my group, the precise same technique had all, bar one, solo in 4-7 hours ...

[Parkbremse]

On the CRJ200 you have the problem that with WING + COWL A/I selected on, the pressure at idle thrust is not sufficient to supply both systems, so you have to increase thrust again up to a certain level. Use of speedbrakes is almost always a must in this situation, especially in the latter stages of the approach when you are descending at minimum clean speed.

Apart from this, i agree with most what has been already said on this thread regrding (mis)use of sb...

[aw ditor]

Was that Trevor Gell?

[aviator3233]

Hi all
came across this question..Can anyone give me an answer:
Speed brakes are most effective when ?
a) During descent
b)In Air
c)On Ground

Thanks in advance

[Wizofoz]

Most effective at what?

They do different things in different phases of flight.

[RAT 5]

If you are considering 'braking the speed' then definitely in the air and level flight. If you are considering increasing ROD then in the air and in descent.
On the ground they are primarily lift dumpers.

[Wizofoz]

If you are considering increasing ROD then in the air

True.

After all, if they increase ROD while on the ground, you are in serious trouble!!
:}:}

[Pakehaboy]

If you need 'em use 'em, and those of us who fly into the good Ole US of A need them an awful lot:D

Those old salty dogs in the left seat who advocate a rolled up newspaper...would get from me, a nice short left jab in return...:ouch:
Yeah mate,back in the day,doing my F/O 727 time,the Cappy AND the PFE would bark at me for using them,called them the,PPPD,S...(piss poor planning device),and occasionally,more often that not get a clip around the ear,now as the skipper I cringe every time I use them.I can still hear those crusty old ba$$tards barking at me in the after life...." You little Shi$$t,you should have started the decent way back when"......I miss those days

[Basil]

I've always considered speedbrake there to be used as and when necessary and am contemptuous of captains who make a huge fuss about them.

[Ex-Brazilian]

Hi aviator3233,

I guess this is question came from an FAA ATP test.

The correct answer is "on ground". But just reviewing the concept of speedbrake, remember that the speedbrake is a function of the flight spoilers, which are also used for rolling combined with the ailerons; the spoilers used on ground are called ground spoilers, they are spoilers that only open on ground. Usually the flight spoilers are also used as "ground spoilers" while on ground, but at an higher angle than in flight. On the 737 aircraft, for instance, the speed brake lever have a flight detent and you should not extend the speedbrakes beyond this detent in flight, because beyond this detent the flight spoilers will open in an higher angle that is designed to be used only on ground. Once you land this kind of airplane, you should see this lever moving automatically to the full extended position; in this occasion, the flight spoilers will be being used as ground spoilers as I mentioned above.

So as you can see, this question is a little bit tricky. But for FAA purposes, choose the "on ground" answer.

[RVF750]

It's pretty actually pretty simple. The "stick of shame" as it was called in my youth is usually labelled SPD BRK. The clue is in the name... The faster you are going, the more difference they make.

Being high and clean at 210kts and sticking them out does not a lot more than make vibration.... At 320kts you can really alter your profile positively.

Most aircraft only use some panels for speed brakes. Some for roll augmentation, and all for lift dumping.

[Jwscud]

All the old boys and girls from the 732 call it the lever of shame.

In modern slippery aircraft like the 738, it is the lever of necessity if you wish to meet stable approach criteria!

[RAT 5]

Given the LOS label I offer the following mis-understanding.
B757/767. High downwind under radar home base, but could always expect a short turn in if ATC perceived it OK, and if a heavy was out on long finals. You are at minimum clean speed, 210kts. ATC gives a large descent change of altitude from FL 70 - 2000' which is a clue. Choices? Extend Spd Bks and keep speed 210kts? Select flap 1, 210kts, speed brake etc. etc. or as many newbies did, select 250kts. They had been told that to increase ROD you increased speed. Speed brakes had not featured in the education. Surely they are there for more than lift-dumping on landing & RTO's? They are a tool to be used as required.
What really did astound me was how many gung-ho top gun wannabes asked for >250kts below FL10 only to use speed brakes downwind as they struggled to slow down to min clean speed or called for flaps at max flap speed trying to remove the excess energy they had imparted to the a/c. Lessons slowly learnt.

[HighSpeedAluminum]

Select flap 1, 210kts, speed brake & V/S 1000fpm

Not a choice for good energy management IMO.

In your scenario SPD BRK and V/S -1000 will work against each other. A/T in SPD mode (Boeing) to maintain V/S. FL CH and full boards if well above profile.

[RAT 5]

You are quite correct. My brain fart and it has now been removed.

[aviator3233]

Thanku people for the answers !!:ok:

[Double Back]

The Fokker F28 was fitted with tail mounted speedbrakes,: they could and would be used during the approach, exactly why I don't know, never flew one.
Possibly because of a non-slatted wing, thus less/not enough drag for an approach.

https://upload.wikimedia.org/wikipedia/commons/6/64/Piedmont_F-28-1000.jpg

[MaydayMaydayMayday]

They don't call it the 'Geneva lever' for nothing! 😄

[RAT 5]

They don't call it the 'Geneva lever' for nothing! ��

Ah. They were expert at LOC + GP intercept 5000' 210kts all at the same time. Testing times.

[Uplinker]

Not using the speed brakes when necessary is equivalent to not using the foot brake in your car. You can manage without it sometimes, but other times you need to use it - especially since you don't always know what ATC's plan and traffic flow situation is. No problem.

[harrryw]

I find it hard to understand why using spoilers to maintain a glideslope will increase fuel use.
On the slope engine is running at low power or idle. Using speed brakes will not change this. It seems that the fuel to land will be the same or less for each scenario. Of course if you land fast higher use of the reverse thrust will use more fuel.

I cannot resist this:
It seems some Captains do not like to rein in their paper waving when reigning over the cockpit. sorry........

[TurningFinalRWY36]

I think the idea is managing your energy earlier on in the approach or descent, if you had of started descending earlier or slowed down earlier there would not be a need for speed brake. The fuel savings would have occurred 20 minutes prior to actually needing the speed brake

[Double Back]

Harryw

You are obviously not a (heavy) jet driver. Approaches on heavy transports, but also on "lighter" fast jets like fighters are ALWAYS flown with lots of power, up to 85%.
Specific approach speeds have been chosen for many reasons: like the lowest possible with that load and flight conditions (1,3Vs) to reduce landing length, a critical factor in most jet planes. Therefore huge flap types are used (see the B747 and A380) with large deflections, creating lots of lift AND drag.
Another one is speed stability, nothing more difficult is a jet that starts creeping away from its desired approach speed (in both directions) and continues to do so. You keep on juggling the throttles, very nasty.
That can be a difficult one to attain for designers, like the B747-400 was OK with flaps at "30" but definitely more "slippery" with flaps "25". One of the reasons for the Quantas incident at Bangkok, although, like usual, more factors were involved there. https://en.wikipedia.org/wiki/Qantas_Flight_1

Jet engines, even the newer ones, still need time to accelerate out of (deep) idle. This can be critical if an immediate Go Around is needed. Carrier based planes do this to the max, as the pilots are trained to select full power upon touchdown, just to have full power if the cable is missed, needing to accelerate out of an idle range would kill them if a cable is missed (bolter).

Accepting an higher final speed because You can;t or won't decelerate is not done in jetflying. Till shortly before touchdown You fight to stick to the approach speed, but NEVER doing that by reducing power to idle. If due to turbulence or wind shear You do end up with an overshoot in speed, You are the deciding part if You GA or think You have enough stopping power on the runway in the given conditions.
Both options have killed pilots and passengers.

So if the design of the plane offers You not enough drag and end up with a too low power setting in certain conditions, like a heavy load or a slight tailwind, planes like the before mentioned F28 have an alternative use of increasing drag with speedbrakes. Specifically the tail mounted ones are less dangerous during final, as they only increase drag and do not kill lift as wing mounted ones do.
The B2 bomber uses "splitable" ailerons to create drag, however I do not know if that is used on final.
https://theaviationist.com/wp-content/uploads/2013/09/B-2A.jpg

As has been said before in this thread, it is not always Your mistake to end up with too much energy, mostly it is caused by other traffic or ATC. Not implicating it is their fault, but as they handle lots of traffic, it cannot always be done with the specific performance of ONE of their "clients" in mind.
Certain airports like Santiago de Chile have the Andes mountains block an optimum descent path, once You cleared the tops, all drag possible was needed to kill energy.

Personally I found straight in approaches the most difficult ones, especially if the traffic was light and ATC did not gave a s**t how You did it with what speed. Curved approaches offer way more options to correct both ways.

To fly an optimal descent in which You have used the kinetic energy to its max is to end up, at or just past point "D" with gear and final flaps coming down and engines spooling up to their normal approach settings. Without ending up in a rushed approach.

I was a line check pilot for a long time and witnessed many crews flying textbook descents and approaches, sometimes without any electronic help, during visual approaches.
Deciding when to crank out the next flap setting is sometimes wonderful to witness how and when that is done. Some pilots just have a wonderful "3D" insight, and are experts in using that, it was a joy to fly with those pros.

[RAT 5]

Of course if you land fast higher use of the reverse thrust will use more fuel.

And it will use even more if screw it up and make a GA.

but NEVER doing that by reducing power to idle.

An interesting sweeping comment. True, the medium/big fan engines take time to spool up again. That process needs to be started 5-10 kts before target speed is reached, if at final flap setting. Not necessarily easy to judge. B737, if already at final flap, I used to advise reducing to 40% on a gusty day as this gave instant response if thrust increase was required. That was well below stable thrust and so allowed enough to slow down and still meet 'stable criteria'. The other point about low thrust or speed brake to slow down is that some types e..g B737 do not allow speed brake >F10. If on approach and with a runaway speed I found too many pilots were hesitant to lower the gear. They were still aiming at the hotshot 500' gate and gear down at 4nm. In an ideal world, perhaps, but if you need the gear then use it. However, in the Trained Mky modern pilot world some are taught to conserve fuel at all costs and the gear down point is specified. That creates a blinkered understanding of energy management.

[harrryw]

@DoubleBack thank you

[Double Back]

RAT 5

True, at one time our management decided to lower the standard final flap setting from 30 to 25 degr. on our 747's in order to save some fuel and wear. Mind, 30 was not PROHIBITED.
Nobody really liked it, as like stated before, the speed stability was reduced, so larger speed excursions on both sides happened.
For non-747 drivers: although it does not look much, the difference in drag btn 25 and 30 is quite dramatic.

At one check flight, the crew selected the 25 setting, notwithstanding:
Max LDG wt, slight tailwind, down sloping RWY, and if my memory serves me right, one reverser U/S (so the opposite also not to be used.)
A screeching halt resulted.
The crew defended itself because that was what the management wanted.
That is a way of thinking I cannot, and refuse to, understand this kind of poor airmanship.

I really never looked a lot to my power setting during the app, after a while the throttle angle gives more than enough indications of how much oooommmph You have selected. So everybody had some kind of "arm length" one was willing to reduce N1 to, if needed.

Of course attitude, speed an V/S are the parameters to look at, so a heavy jet is basically not much more than a C172. You can land a B747 visually with only IAS, nothing more is needed. Surprisingly many runways that lack an ILS need to be flown like that.
(OK, I am of a pre-GPS approach generation.....)

[RAT 5]

Your story is scary. Management is for managing. Airmanship is for operating aeroplanes as the situation demands. I did have some interesting discussions with young F/O's who insisted on landing F30 (B737) disconnecting auto brakes with large feet and pulling FULL reverse to make a turn off; because F30 was company standard?????? The idea that some runways and ambient conditions cause different thinking on the day was a surprise. Unless F40 was specified in the airfield brief there seemed be great reluctance to use it. GRO RW20 downhill, wet, slight tailwind and still a F30 VMC 500' gate was briefed. Hm?????

[ELondonPax]

Humble passenger here. Am I correct in thinking speed brakes are always used on E170 / E190 and 146/RJ into LCY - steep approach and all that. On the E170/E190 it does create noticeable vibration.

[RAT 5]

Broadening the discussion: what opinions about the use of full or partial speed brake application? I know the recommendation is often full or nothing. Sometimes I found full caused too much rumbling; and having sat amongst nervous pax it felt un-nerving. Thus I usually used up to the rumble strip deflection. Other scenarios were when I was high approaching the GP from above I used SpdBk to give me a ROD to reach GP intercept at correct speed and ALT without any level off, and in a smooth manner. The diversity of reactions was interesting including those of 'plain wrong'. One company had an SOP for everything and there it was written all or nothing. I used to hate those straight-jacket restrictions that left no option for technique/finesse & best for the moment decisions.

[Double Back]

When the need for SB was expected we were advised to warn the pax about the rumble, which on a B747 was clearly noticeable and audible.
(BTW the same if the gear was to be extended at a higher than normal speed)
It was left to the PF if they were opened full or partly. At about 3/4 of lever travel there was an area with more friction. If not dealt with cautious, the lever would slam to the stop and pop up the panels too fast, which was not quite pax comfort wise.
In general it was known that as of 250 KTS the effect was far less as above 300 KTS, and as You were in the flap/LE range, extending those was more efficient.

I once ended up about 60Nm from the destination, before getting the descent clearance, so heck, we made an "emergency descent" with full SB and 350 Kts, all the way down to 1500' to downwind (over water), levelling off and decelerating with SB open, cranking flaps and gear while turning base, rolling out on final for a stabilised visual.
Yes, it was StMaarten, (but it wasn't me that made the famous low app :) :) )

[misd-agin]

Remember the good old days, when guys would descend 30 miles early to make sure they didn't use the speed brake? Or put the flaps out at the highest speeds allowed so they wouldn't use the speed brake? Or lower the gear at high speed, miles early, just so they wouldn't use the speed brake?

Gas wasted? Noise? Beating up the airplane? Not my problem! I didn't use the speed brakes and that's what counts! <sigh>

[Double Back]

I also remember (on the DC10) which was restricted in SB use to clean config. only (if I recall correctly), it was warned that the combined use was said to be like "stripping the bird of its feathers". We all thought it would stall vicious if You would forget about this!

It was quite a shock to migrating ex DC10 pilots that the good ole 747-400 the SB was allowed till and including flap 20 setting, which features full LE extension and already all flap panels out.

[Uplinker]

@ misd-agin, good post. Like I said, one can compare using speed brakes to using the brakes on your car; you can sometimes manage without using them, but you usually have to make compromises in other areas, eg, in the car example; separation from the vehicle in front.

It is nice not to have to use speed brakes, but when you need to, why is it such a big deal with some folk?

A Cap once told me not to use speed brake in a 330 - I had barely cracked them open, so there was no vibration or rumble - just to prevent getting high on profile by adding a few hundred feet per minute to my V/S. Right, I will teach you I thought, so I did the whole descent and approach and intercept without touching the speed brakes from that point on. We were cut in a bit by ATC and everything was at the far end of just reasonable the whole way down. I managed it, but you should have seen him squirm!

[misd-agin]

I see enough guys that know they're going to need speed brakes but instead of using partial speed brakes, which can be unnoticeable, they wait until the last moment and 'light switch' the speed brakes - Bam! Full speed brakes, Bam! Immediate retraction! Done! Comfort? Enjoyment? Who cares!
I pity their wives....

[RAT 5]

Not using SB? The reverse side of the coin are the hot-shots who have a perfect VNAV PTH to GP intercept. They are on profile with 250/100. They then ask for >250 below 10. ATC agree and continue with radar vectors. Guarantee they either ask for F1 at limit speed or have to use SB's. The 1st is refused and at the 2nd my eyebrows are raised in questioning.
In answer to the 1st I remind what FCTM says about flaps as speed brakes (not) and the raised eyebrows asked the question "do you accelerate towards red traffic lights?" The runway = landing & requires you to lose 40% of your speed, so why accelerate? Blank stares!