B737 Classic - Manual Speed Brake use on Landing

[SocaPilot]

The Boeing 737-300 FCTM states that "Speed Brakes" should not be used below 1000 Feet AGL. (Agree and understand the logic with this statement from Boeing). I think this statement is true from Boeing with reference to most if not all of its aircraft series.


However, is deploying the Speed Brake manually during the landing roll at 3 to 4 Feet above touch down considered an infraction to the above statement.


I have been advised that 3-4 Feet AGL is not considered "Flight" mode and further that ICAO defines the landing mode as 50 Feet AGL to actual touch down and rollout. Is there anyone in these forums that may be an actual Boeing Technical person or other wised experienced who can answer this question correctly and possible provide documentation to this effect.


I do know that Boeing in the early stages of Auto Speed Brake introduction on its aircraft, placed a sensor in the system allowing the Thrust Reversers (Auto Speed Brake included) to be capable of being deployed at 10 Feet Radio Altitude.


Pilot Question for ALL - Scenario = Landing Flare / Floating occurs about 4 Feet off the ground. Pull Speed Brake manually and put aircraft on the ground or execute a Go-Around?


Looking forward to receiving the professional comments I have been seeing in these forums.

[exeng]

However, is deploying the Speed Brake manually during the landing roll at 3 to 4 Feet above touch down considered an infraction to the above statement.

In my opinion yes for quite a few reasons.

[Mach E Avelli]

My understanding was that the non use of speed brake at low altitude was more to do with increased roll response than any likely deployment of the lift dump system. The latter would only deploy after weight on wheels.
It was not a limitation, but rather a recommendation.
Perhaps the FCTM has become more explicit since I last flew the type several years ago.
But regardless, messing with any flight control configuration change in the flare seems to me to be a bad idea. If you are floating, you already buggered it up, as the B737 is not inclined to float if the speed is correct and thrust levers fully closed in the flare. If you are not on the runway at the desired point, bug out and have another go rather than risk a heavy landing or pod scrape.
I once experienced a full lift dump deploy in a Bae146 at about 100 feet when the trainee F/O pulled the speed brake through the gate. Not her fault, as the squat switch system had malfunctioned and the aeroplane 'thought' it was on the ground. The result was quite dramatic as the nose pitched down, requiring full back stick and a great fistful of thrust to cushion the landing. It is unlikely that a go around would have been possible in that configuration, so it was just as well it happened at such a low altitude. A less forgiving type like the B737 may not have been as malleable.

[nitpicker330]

Pulling the speed brakes before touchdown??????????

I've seen guys select reverse slightly before touchdown and it didn't seem to make the landing too hard.

Speedbrake?? How's about you try it first and let me know how it goes.....:D

My advice is DON'T DO IT...

Edited::----I just have to say I don't recommend selecting Rev before touchdown either..

[Mozella]

Rather than learn how to deploy speed brakes in flight, why not learn how to fly your aircraft at the correct airspeed? I've never flown the 737 but I have flown several other Boeing aircraft as well as many other types.

In my experience, if you control your airspeed and execute the flare properly, the aircraft won't "float", speed brakes aren't necessary or desired, and everyone will be happier if you fly on speed. It takes a bit of concentration, but it really isn't rocket science.

I'm retired now, but I can also tell you that had I ever deployed speed-brakes to force my aircraft on the ground I'd most likely wind up doing a rug-dance in the chief pilot's office. My airline strongly discouraged cowy flying.

I don't know the statistics, but off the top of my head I can think of more landing accidents caused by flying too fast than flying too slow.

[glendalegoon]

the 10 foot altitude/radar altitude thing is in case the WOW switches don't work you can still use reverse.

listen pal, don't put the speed brakes out at 3 feet. stow them before 1000'. be sure someone calls SPOILERS on touchdown.

People who use little tricks like reverse before touchdown are asking for problems.

Don't be one of those people.

[blind pew]

Many moons ago there was a DC 8 lost when the FO messed around with the speed brake....hit very hard...during the go around the main spar failed IIRC.

[Skyjob]

Deploying the speed brake in flight is NOT allowed below 1000' AGL for many reasons, to name a few:

decreased climb performance if not stowed
sudden incresed sink rate towards surface
auto speed brakes may not function as advertised in case of missed approach
manoeuvre margins are decreased


FCOM FCTM:

If a go-around is initiated after touchdown but before thrust reverser selection, auto speed brakes retract
manoeuvre margin decreases at any flap setting when speedbrakes are extended
Use of speedbrakes between the down detent and flight detent can result in rapid roll rates and normally should be avoided
If higher than idle thrust is maintained through initial touchdown, the automatic speedbrake deployment may be disabled even when the speedbrakes are armed. This can result in a bounced landing. During the resultant bounce, if the thrust levers are then retarded to idle, automatic speedbrake deployment can occur resulting in a loss of lift and nose up pitching moment which can result in a tail strike or hard landing on a subsequent touchdown


Deploying reversers before touchdown is NOT allowed (but possible) for amongst others:

Committing to land before touching down
Landing performance takes into account reverse selection and spool up
thrust deployment reverser problems can lead to asymmetric thrust conditions
thrust surges when selecting reverse can lead to asymmetry thrust conditions and added workload due startling factor


FCOM FCTM:

WARNING: After reverse thrust is initiated, a full stop landing must be made.
Immediate initiation of reverse thrust at main gear touchdown and full reverse thrust allow the autobrake system to reduce brake pressure to the minimum level.
The importance of establishing the desired reverse thrust level as soon as possible after touchdown cannot be overemphasised
Distractions arising from a malfunctioning reverser system can also result in delayed manual braking application
If an engine surges during reverse thrust operation, quickly select reverse idle on both engines.

[stilton]

Seen it done, on a B727 as a junior Second Officer / Flight engineer.


Landing at LGA, Captain floated halfway down an already short runway, instead of going around he pulled full speed brake while we were around 5'


I've never experienced an impact that hard, we dropped every oxygen mask and every over head bin.


No problem stopping, your basic crash removes most energy quite well. I learned to be a lot more assertive after that, despite being on probation at the time.


I did did insist on a hard landing inspection, there was no damage, the 727 was a a real brick sh*thouse.


Don't think an A320 would have faired as well :eek:

[Centaurus]

Don't even think about experimenting when all the info you need to operate a Boeing safely is in the various manuals. That is why Boeing have qualified test pilots to test the aircraft in various configurations before releasing the aircraft for incompetent airline pilots to fly. And there is no shortage of those judging by spectacular accidents around the world. Hello Asiana at SFO:ugh:

[Capt. Inop]

Speed Brakes" should not be used below 1000 Feet AGL

For very good reasons unless both engines have failed.

(On the longer NG's it's a big NO NO).

Be on speed, the B737 won't float unless you try to land too fast.

[Rick777]

Blind pew, I've never flown the DC8, but I thought it didn't have speed brakes which is why reverse on inboards is available in flight. Am I wrong?

[Centaurus]

Be on speed, the B737 won't float unless you try to land too fast.

Any aircraft will float if you leave power on and hold off high. The 737 will too. Seen it many times.

[ZeBedie]

Any aircraft will float if you leave power on

It's called the cruise :rolleyes:

[oceancrosser]

Blind pew, I've never flown the DC8, but I thought it didn't have speed brakes which is why reverse on inboards is available in flight. Am I wrong?

No you are not wrong. The DC-8 had Ground Spoilers which were armed before landing. Unfortunately in a few cases these were activated in the air and some aircraft either lost or severly damaged. Iirc they were tied into the air/ground logic after that.

[john_tullamarine]

Seen it done, on a B727 ... he pulled full speed brake while we were around 5'

No doubt a -100 ? Pretty much a pussycat.

5 inches off the ground would get everyone's undivided attention on the -200 if you were lucky enough not to break something. A top landing on the -200 was a real head sweller - if somewhat unnerving .. only ever had one of those ... the rest tended to be in the very average basket ...

[Hobo]

I've seen guys select reverse slightly before touchdown and it didn't seem to make the landing too hard.

Standard practice on the HS121 (http://en.wikipedia.org/wiki/Hawker_Siddeley_Trident) on short/contaminated runways. Used in the descent you could get circa 12000fpm out of it!

Neither of these was ever a problem...

[vilas]

Is there no concept of unstable approach in B737? If you need speed brakes below 1000' shouldn't you be going around?

[No Fly Zone]

I've read this a couple of times and read the several responses. I understand the situation. My thoughts are: 1) if you have not already executed a GA, why not? and 2) 'creative' flying is not for commercial operations.
If you have a better idea, write to Boeing. They HAVE changed procedures before, but never without thorough testing. This one will never qualify simply because it cannot be used is all or most situations. It is still better to GA and set up a new approach. Always.

[vilas]

No Fly Zone
What you said is absolutely correct. I can't believe what is being discussed here which is down right dangerous and an accident in the making. The very concept of stabilised approach is absent. All the talk about ALAR seems to be thrown in dustbin.

[Goldenrivett]

Hi SocaPilot,
Scenario = Landing Flare / Floating occurs about 4 Feet off the ground. Pull Speed Brake manually and put aircraft on the ground or execute a Go-Around?
If you are floating (over flared), then why not lower the nose by a degree and land within the touch down zone? I've never pulled speed brake during the flare and don't intend to.