PDA

View Full Version : Is manual braking seen as dangerous?


Hudson
9th Feb 2004, 21:19
Interesting in the simulator to see pilots weaving and jerking down the runway when asked to demonstrate competency at carrying out a normal landing without the help of auto-brakes.

Already we have operators who see raw data practice as unecessary and even undesirable from the flight safety point of view. They point out the reduntant nature of glass cockpit instruments and claim that like engine failures at V1, an unplanned truly raw data approach and landing will in all probability never happen in a pilot's lifetime.

I was appalled to hear one automation dependant pilot describe those who enjoy polishing their raw data skills as, "Raw data heroes". So what about raw data braking? I think that is rather a natty new term, don't you.

Boeing recommends that whenever runway limited, using higher than normal approach speeds, landing on slippery runways or landing in a cross-wind, the autobrake system be used (737 FCTM quote). Sounds good to me.

So what is wrong with using manual braking when the circumstances dictate - which is surprisingly often if you accept the Boeing recommendations above. After all, using the foot brakes to pull up should not be that difficult to a competent pilot.

Is it my imagination, or is there a steady dumbing down of the manual flying skills once considered so vital for survival in the air.
A rusty unstable raw data manual throttle landing approach - harsh and uneven manual braking through sheer lack of exposure- what a pity to see true handling skills erode because laziness.

Is manual braking, for example, really dangerous? Or is just too much bother and in any case who wants to look a twit in front of the first officer? :ok:

Spearing Britney
9th Feb 2004, 22:41
I think you are highlighting a potentially serious issue. The number of times my requests to conduct an approach without the auto-pilot/thrust/brake produce a look of horror and a refusal definitely concerns me. I'm not talking about hand flying from 35000' to landing in IMC at Heathrow when the stacks are all full either. I'm talking about quiet, well run, good weather fields. Sadly my last company largely condoned this approach - I was often quoted 'the use of autobrake is recommended' and the rest of the passage in the manual allowing manual braking in certain circumstances was ignored. :(

I don't think that it is laziness causing this marked and widespread (my opinion) decline in the frequency and quality of our manual flying skills. I believe it is fear; most company's now seem to advocate regular use of the automatics to help reduce overspeeds/brake wear/unstable approaches etc. The part of the SOP's which allow (but rarely advocate) manual flying practice is overlooked because of how hard the management of various outfits have come down on crews who have suffered tailstrikes etc when flying (admittedly sometimes inappropriately) manually. I see this as an arse-covering exercise...

m&v
10th Feb 2004, 03:26
Not dangerous but some people in order to 'clear' the runway realy 'hammer' them(brakes) on.the temps' rise and the bean counters scream Cost.Auto braking ,like the Auto pilot should not relieve the pilot of his piloting skills(the autopilot won't always be there-to be selected at 50')In view of this philosophy pilots should be encouraged,as in United?,to Handfly as much as posible(in low density traffic areas).No aotopilot selected,sometimes auto thrust off(as in the Mountain wave scenario)and with no autobraking on,ease the brakes on, use the runway.In my term on the a320 I encouraged all of the above.After all the junior group don't have the 727 to 'learn 'on.:O

CaptainSandL
11th Feb 2004, 03:50
I agree with Hudson and Britney that this is yet another area where Company’s who appear not to trust their own pilots are trying to get them to use all of the automatics for as long as possible. Thankfully I am not the only one who sees this as short-sighted because come the day that those automatics are not available you will probably not be up to standard at operating the aircraft without.

For instance, autothrottles go u/s - especially on older 737’s! I have watched pilots with some years on type who clearly do not have a feel for their thrust settings or rate of application/reduction of thrust when reaching the desired altitude. This would not be the case if they were competent at raw data flying.

Example number 2: There is a current warning on very new 737-NG’s that if TOGA is pressed above 400ft agl after take-off, the roll command bar of the flight director will disappear. How will the non-raw-data-current pilot cope with that at 500ft in IMC in an SID turn?

To come back to the thread, my own company’s policy on autobrake is “It is the company norm to use autobrake on landing.” And I was once pulled up for not using autobrake on a line check into AMS R/W 18R (approx 12,000ft and you have to taxi to the end to reach the terminal) even though I had briefed my intentions to the F/O.

Sometimes I really worry about where pilots handling skills are if they have only known airlines who discourage hand flying.

S & L

HOMER SIMPSONS LOVECHILD
11th Feb 2004, 08:09
Hudson,perhaps you've been spending too much time in the sim.I have never yet encountered a sim that handles remotely like the real thing.This difference is particularly marked on the ground roll and I for one would tear up my licence if I weaved around the runway in real life like I do in the sim.(autobrakes or not)

Flight Detent
11th Feb 2004, 11:03
Hi all,
As regards autobrakes, I always recommend that the PF not use autobrakes at all, but select normal thrust reverse ASAP after touchdown, and then use the brakes as required below 80 knots.

This way, we never seemed to get 'hot' brakes, as we so often did with using "MIN" and normal reverse.

Although the company (AAI), used to recommend "MIN" autobrakes for all landings.

Even medium to heavy use of the brakes below 80 knots never seemed to get the brakes as hot as "MIN" autobrakes.

It works, try it!

This was B747 Classic.

Cheers

PS. Boeing says that full manual footbrakes will stop you faster in dry Wx, than will "MAX" autobrakes, and you can choose when to start ie. after the NLG is on the hard stuff!

Hudson
11th Feb 2004, 19:10
Homer.S.L.C. Good point about the simulator fidelity. However after watching the ducking and weaving syndrome I did a few landings under varying conditions in the simulator (anti-skid inop, one engine inop, crosswinds etc, and found that the fidelity of the brakes was excellent when compared with my experiences on the real thing.

Since first flying the early 737's circa 1977, the 4 different companies I worked for left auto-brake policy to the captain's judgement. Few resorted to auto brake use.

Certainly brake wear and tear was reduced with intelligent use of reverse thrust and manual braking. On the majority of occasions brakes were not needed until around 80 knots, and because of this cool brakes were the norm, which made the next crew to take over the aircraft very happy. No one likes to take over an aircraft with hot brakes, for good reason.

With the steady march towards full automation, I believe that it won't be long before auto-lands will become the preferred method of landing even under sunny day dry runway operations.
If and when that sad day arrives it will mean manual skills will erode to a potentially dangerous degree.

I am reminded of a paragraph I read in 1991 in the Operations Manual of an airline called Germania. In discussing company automation policy it said " Manual flight is to remain an exception"

BizJetJock
11th Feb 2004, 19:40
I believe all you chaps are talking about pedal braking. "Manual" braking would involve some considerable contortions to get your hands on to the brake pedals during the landing roll, and I would certainly consider that dangerous!!!:ok:

But seriously, I agree that it is criminal to stop pilots from practicing their skills so that they are there when really needed. Of course, the primary reason why the automatics often do a better job than the pilot is precisely because (s)he hasn't been keeping up to speed.

Lemurian
12th Feb 2004, 00:25
Met a chap the other day who told me he uses autobrakes on allhis crosswind landings as he tends (like all of us,I presume) to overheat the brakes on the downwind side.He has been doing it for years.

m&v
12th Feb 2004, 10:00
Now that is one area I would 'encourage' Autobrake usage.With strong crosswinds ,set up the braking required -concentrate on keeping it straight..Works well...:O

Hudson
14th Feb 2004, 13:41
The 737NG auto-brake setting can be changed during the landing run above 60 knots. I have seen pilots carry out a perfectly good landing with auto-brake 2 previously selected, then shortly after selecting reverse thrust, reach over and turn the selector to auto brake 3. Seems a pointless exercise and even a bit gimmicky when all they had to do is to lean on the brake pedals to disconnect the auto system for any additional braking.

Is this yet another case of gimmicky switching just because it can be done - regardless of the usefulness of the exercise?

alexban
15th Feb 2004, 19:03
Flight detent :'This way, we never seemed to get 'hot' brakes, as we so often did with using "MIN" and normal reverse.'
The autobrake system calculates a deceleration rate which is dependant of the use of brakes and reversers.In the 737 if you select
MIN (1) brakes and use normal revers the amount of pressure applied on the brakes will be almoust zero after the reversers deployment.
The use of autobrakes till 80kts will minimize the brake wear,no matter what types of brakes disks you have.Also the autobrake system acts faster,and better than human reaction,no matter how good a pilot you are.It is a computer.
This is a technical point of view.
In our comp we use autobrake to initiate braking,then ,deping on the situation (need to expedite vacating..) we use manual braking.
Nevertheless,the decision to use manual or autobrake is at the decision of the PF.The SOP is not rigid on this matter.The younger fo's are encouriged to use manual braking ,if they want to.
And also manual flying,whenever adequate.I ,for myself,won't like to become a magenta pilot,as many of us are these days,due to automatics and rigid SOP's.
Alex :ok:

Ignition Override
18th Feb 2004, 13:06
Captain SandL: concering autothrottles, one Captain offered me two extra legs to fly (on days where we had three-four legs each) because the autothrottles were inop per MEL.:D

Except for the DC-10, along with a second, totally different aircraft fleet, the more senior and experienced a pilot is, the more automation he/she has and the fewer legs they fly (except for some A-320 trips).

Never mind being pampered by flying medium or long legs overseas.;)

notjustapilot
18th Feb 2004, 16:50
Few comments in addition to your valuable thoughts.
'AUTO', as a term, is a sequence of actions programmed by human beings to serve commonality needs as well as to prevent errors and facilitate procedures. Which, at the end of the day will, minimise cost (hopefully!).

Being aviators, we are all aware of the good old saying ... 'every flight is different'. Should we take that for granted, it's almost impossible for those brilliant software designers/developers to consider every single stage of a flight and structure a 'human reacting' software.
Considering ourselves as pilots and not observers...I believe that every airline that trust and respect its crews (and that's the case, isn't it?) SHOULD ENCOURAGE THEM TO MANUAL FLYING under certain conditions.
Isn't it true that by flying we add experience and skill?
How can we achieve that if we log our flight hours to the software guys?

Being a A320 captain allow me to ‘take you’ through a normal day's routine.

…Cleared for T/O
Increase thrust to .50 "thrust stabilised"
Click-Click "SRS, RWY, FLEX"
Maintain rwy heading (big deal!) V1, Rotate.
Positive climb, gear up, select autopilot 1.
Acceleration, flaps 0
Managed
FL100 cabin crew released
Ding-Dong....High Jenny, "Newspapers please"
.....
Briefing, descent procedures, Radar Vectors, ILS captured, A/P 1 and 2 CAT3 dual, auto brake to low, LAND GREEN...touch down.
Spoilers armed, reverse green, decell ... full stop.

Did we touch the airplane at all?

Question.

What if the above scenario is true but …
X-wind component exceeds the auto land limits and or destination data is lost (it happened to me twice and thrust went to TOGA as the FMGS considered the A/C being in a go-around mode...in IMC) and or auto thrust trips-off?

Answer

We still need to fly this A/C safely to destination. In other words we still need to use our good old professional skills. It’s always an airplane…and that sounds to me like … WE HAVE TO MANUAL FLY THOSE BABYS FROM TIME TO TIME!