"Guarding" the controls while on autopilot
 

Things never cease to amaze one. When the automatics are engaged with the aircraft below a radio altitude of 2500 ft, an operator in this part of the world requires that the PF actually rest one hand on the thrust levers and the other on the control wheel "following through" on the automatic pilot and autothrottle movements. This is termed "guarding" the controls.

Presumably this is in case the automatics suddenly give up the ghost.

One would think if this is a valid reason for "guarding" things, then the same policy should apply if the PF is hand flying below 2500RA and the PNF should have his hands on the controls as well as the PF and also over the PF's hand on the thrust levers just in case the PF should suffer sudden incapacitation. What a strange way to fly an aeroplane.

Most pilots dislike having the other pilot "hovering" over the controls at any time.

The 737FCTM under Cat 3 Operations recommends guarding the controls on approach and through landing.

How do you define the term "guarding". Does that mean hands actually grasping wheel and thrust levers in a claw like grasp - or does it mean hands resting relaxed on knee ready for a quick take over?

Hi Centaurus,

Yes we do that on the 767 too. Yes its to guard against the aircraft suddenly doing a dirty dart due to some type of aircraft or ground aid failure..more likely when doing a practice autoland when Low Vis Procedures are not in force.

There have been cases of aircraft suddenly doing a dirty dart stage left/right and I guess this gives you the extra nanosecond required to correct the problem...we actually hold the relevant controls as if flying the aircraft...only lightly of course.

Mind you in every failure scenario I can remember in the sim the aircraft continues on it's stately way via the IRSs....can remember in initial AWOPs training not noticing a complete ILS transmitter failure below 1000 radio...the aircraft continued on as if nothing had failed and landed itself normally:}

Did you do Cat3b stuff in the 737s you flew in Europe?

We do 3b no decision...ie 75m vis 0 cloud base...taxiing is the harder bit;)

I must say it does make sense to me to have the PF's hands on the controls during an autoland....for starters you need to have your thumb poised over the GA button if someone strays into the protected area and bends the localiser signal. That happened to me in the sim...scares the crap outa you when you see the HIALS out the left window at 50R.

Chuck.

The issue of guarding the controls is also related to the knowledge about automatic systems in general – how automatic is automatic, and what are the design and certification assumptions?

Thus for older aircraft with ‘fail hard’ autopilots it was definitely hands on.

For more modern ‘fail passive’ (fail soft) systems then hands off is quite acceptable in the cruise. In the event of a failure, the certification requirements should limit the pitch excursion to approx 1 deg / sec (300 ft alt in 4 sec) and less than 15 deg / sec roll (60 deg AOB in 4 sec); most autopilots will disconnect automatically. The cert assumption is that the crew will be in the loop within 4 sec. With some aircraft there has to be a balance between the crew deciding to be hands on and them not fighting the autopilot or attempting to overpower the system (with potentially hazardous results).
During the approach and landing, whilst the cert requirements are tighter (crew involved within 2 sec) it is more sensible to guard the controls. Some aircraft specifically require the crew to be hands on i.e. for the Avro RJ to accommodate extreme conditions, hands on (follow through) is required to damp/prevent a low amplitude oscillation, which the cert standard would not allow, but I doubt if it would ever be seen in service.

For landing with fail operational systems then hands off would be more appropriate as the auto-land (even after the first failure) will perform far better than any crew i.e. the crew are more likely to fail / screw up than the system.

Personally I choose to follow through on the controls whenever possible; for those systems that back drive the controls the pilot gets a feel for how hard the auto pilot is working and whether it is in touch with the aircraft motion; a bit like supervising a student pilot.

Now apply that principle to other automatic systems; how do you maintain hands on for an automatic fuel transfer system? Is the system fully automatic or only just automatic?

With apologies to co-pilots and autopilots:
“An autopilot is like a co-pilot, but never learns”
“A co-pilot is like an autopilot, but can forget”
--------------------
Airspeed and Upwardness

Our SOP's state that the PNF must guard the controls below 1000ft RADALT, regardless of whether autopilot is engaged or the PF is flying manually. This means that the PNF places one hand behind the throttles (but doesn't physically touch them) and the other hand on his knee with hand upturned ready to grasp the control column if required.

Seen the autopilot flick off numerous times due to turbulence/shear below 1000' and thats in an aircraft designed only 10 years ago!!

With autothrottle connected, the PF will generally have his hands actually on the throttles as our autothrottle lags behind by up to 10 knots (both fast and slow) and when configuring with autothrottle, can quite easily overspeed the gear.

Air Berlin SOP is that the PF keeps it's hands on controls AND throttle until 10.000', auto-pilot engaged or not.

Despegue. Are the automatics really that unreliable in the 737 that you really have to have all hands on wheel and thrust levers to 10,000ft? Surely the automatics would not have passed certification flight tests if they were that bad. Seems like a gross overkill to me - especially as the Boeing advice is to only guard the controls during a Category 3 landing.

Menen,
My opinion too, but try and tell that to the guys who make the SOP's...
Furthermore, I like to have both hands on the control wheel whenever autothrottle is engaged.

despegue
 

In that case wouldn't one hand on the yolk and the other on the throttles, (ready for a quick disengage if required), be a better option?

With our outfit PF covers controls whenever flaps are extended (i.e. closeish to the ground)

Blimy, hope you don't fly longhaul. You would struggle a bit after a 13 hour flight.

:P

L337

If your reactions are such that you cant move your hands from your knee to the column in a split second, should you really be flying an a/c?

Always makes me smile how many pilots are not relaxed enough to be on a flight deck, you know the type that feel they have to hold their mike every time they transmit!

whatunion
 

Just wondering if you have ever used the old style Airmed headset or similar? On those the boom mike often dropped down below an acceptable level under the chin and had to be held up for satisfactory transmission. Later, more expensive, model headsets seem to have cured this problem.

Yes i have and know what you mean but in our company everyone uses the same headsets and the mikes stay were they are set.

Seriously, i have studied those who always hold their mikes when transmitting and these are the ones that get up tight about everthing from turbulence to slots!

Funny old thing, I was was just thinking about this very subject when I happened upon this thread...

I have observed a large range of behaviour from many people over the years, ranging from only touching the controls if absolutely neccessary to hanging on for grim death at all times!

These days I sit in a large FBW beast with (a) very reliable autopilot(s), so I tend towards the former and let go as soon as the A/P is engaged.

I do profess to a (irrational?) slight degree of annoyance when the PF insists on staying physically connected to the aeroplane even when the electronics have taken over. It makes the PNF's job harder as you often find a marked reluctance from the other side to 'let go' of the comforter and make FMC & MCP changes and the like. It also runs somewhat contrary to our SOP's.

My real fascination is with what these guys think they are achieving with their white knuckles (showing through the gloves). I have seen blokes with their hands on the yoke for half an hour in the cruise in light turbulence.

There are two main states of man and machine:

1) A/P out, pilot flies aeroplane.
2) A/P in, A/P flies aeroplane, pilot tells A/P how to do it.

Granted, in the latter stages of a CATIII approach, it would seem to be wise to 'guard' the relevant controls but at FL370?

My point seems to be shaping up thus: If you are happy with the A/P, leave it alone; if you are unhappy, take it out. There is no 'middle ground'.

You cannot instill a idea into the A/P or A/T by pressing on the controls or hanging on the thrust levers. At best, nothing happens; at worst the A/P goes into some other mode (CWS, V/S or whatever) and you don't notice because it hasn't disconnected...

In short, to get the A/P (or any automated system for that matter) to do what you want, use the INTERFACE PROVIDED BY THE MANUFACTURER and follow the protocol demanded.

As I said earlier, it's more a point of interest and I don't really care what other people do. I'm sure the earlier generations of aircraft had to be watched continually and A/P failures were frequent. After nearly 5000 hours on my present model and no A/P dropouts maybe I'm getting complacent...

Keep pressing the buttons.

What does your S.O.P say about guaring rudders and brakes?

Most common cause of sounding like your head is in a bucket is holding the boom mike - don't do it! If it keeps drooping I hear modern medicine has a cure ;)

Having had a 737 decide to dump it's autopilots just before the flare on a CAT 3A landing and a 757 trying to barrel roll on a triple channel approach when following a 747, you won't see me not following through on the controls when established on the approach - I value my life too much!

I find that the command RETARD wakes me up sufficiently to remember to put my coffee down and touch something..................

After that it's anyones guess what the landing will be like :ok:

Let's see now. A/P engaged and pilot has hands on knee monitoring the automatics. Something dreadfully critical happens and after the normal one second human response delay, one of the two monitoring pilots grabs the controls. That would take maybe one second.

Scene 2. As above except automatics engaged but PF (or PM, if you so desire) has mitts on controls as well. A dreadful event occurs and after the one second evaluation period the PF tightens his grip on the controls. That takes maybe half a second.

So now we are looking at an emergency that is so deadly that one half of one second is all there is between life or death.

Seems there is no shortage of nervous nellies masquerading as airline pilots.

During a bog standard CatIII approach, (a regular feature in Europe for several months of the year), the PF will have one hand on the control yoke, guarding the auto-pilot dis-connect button, and one hand on the throttles guarding the auto-throttle disconnect/ TOGA switch, in the event that at any time any indications shouldl move outside the accepted parameters for an autoland under CatIII conditions, then the PF will take immediate control of the aircraft and carry out a go-around/over shoot. On the B747-400 this situation could occur at a height of 20' agl and no visual reference outside the aircraft.

Under such circumstances having ones hands on ones knees is not recommended, but if in doubt, try it out!

During approach and landing , the flying pilot should be guarding the controls and ready to take over any time , flying is an attiude and flying during critical stages of the flight needs more attention and good lookout, I've been watching pilots sitting x-legged and hands on top of each on chest , and many behaviours like looking for something in their briefcases relying on automation , removing their feet from rudder pedals.It does not look good and may be only one day in your life you'll find out it is very important.

Johnman has it right. Guard the controls ie, have your hands and feet ready to take control, resting very lightly on the controls, just in case the billion-dollar automatics decide to abandon you at the critical moment (which they will, if you have my sort of luck). Have a nice flight!!

Even with calm winds on a clear day, if you fly the glideslope/loc on autopilot and any other plane is near the ILS transmitters or you have wake turbulence, the plane will fly in a way that will scare some passengers. The other planes are only held well clear during Cat 2/3 approaches, or if an ILS 'hold' line is designated.

Do you know your planes' limits and your own comfort limits?

By the way, don't all (real) pilots want to hand fly many of their approaches, unless the ceiling is less than 1,000' or the visibility is somewhere near minimums? Even after 'flying' the 757 for over three years, I only saw Captains make a required (once a month) autoland about two or three times, total, because it is so easy to fly by hand. But even a normal 'altitude capture' might not go smoothly so just disconnect it and reselect one of three autopilot buttons. A Lufthansa A-340 pilot told me in SFO that his plane once made a sudden 20-25 degree roll during climbout in Munich behind a 757(!), due to wake turbulence. Anyway, some of our 757 Captains often hand-flew departures to above FL 180...or so. If some pilots are afraid to hand-fly or are required to use automation all the time, that would seem really strange to me. This topic reminds me of another one on Pprune. Some younger pilots seem confused about who is really working for whom, i.e., the one in the seat versus the autopilot/VNAV/LNAV/autothrottle systems?? :suspect:

One of the pilots who works "over there" (from the "native tribes") told me that in the UK the airlines are not really interested in piloting skills. If so, do they feel that piloting skills are just for smaller planes because automation is always a safer substitute? Could some Flight Standards Departments around the world have actually desired years ago that the highest levels of flight automation be developed as a substitute for very low experience levels, because the time for this experience to accumulate bothered them? Do some departments therefore demand that pilots always leave automation "in command" because hand-flying most of the departure and approach makes them uncomfortable, or don't want the non-flying pilot to be then constantly pushing buttons on the MCP and FMC? confused:

and they say PILOTLESS COMMERCIAL AIRCRAFTS SOON.

IgnitionO w.r.t. 'UK the airlines are not really interested in piloting skills' - sorry to report but that's not true. Veritably many of our Ops Manuals specifically state that we should guard against erosion of hand-flying' skills.

Indeed, to help make the point, I recently opperated the following flights in a B737-300 :

Departed in darkness from London-Gatwick ( en-route Innsbruck / INN; it being a Cat C airfield worthy of considerable respect ) with both autopilots u/s. On approach (LOC 26) to INN weather was such that at MDA we were unable to see anything at all ( except heavy snow and a big dollop of ice on the wiper nuts & wings ) so, "GoAround" followed by diversion to Munich. The whole trip, and return to LGW, was hand flown; When we got back to LGW the next flight, by a different crew, similarly despatched ( sans autopilots ) for Tenerife and back ( were at just over 4 hours in each direction, plus a turn-around in the middle, that's got to be a long night ! :uhoh: ).

Departure from Stansted during which both Flight Directors failed. Ergo no autopilot or lateral / vertical guidance - and we coped admirably.

Now I could go on and on with examples but, needless to say, we're actively encouraged to disconnect the 'automatics', get hands-on with the beast and keep our scan sharp; However, that said, there's the time and place ( along with crew experience levels ) to be taken into account and if, say, the TMA is busy we prefer to have the autopilot ( if available ) engaged until establised on the GS - doing so helps to keep it safe. :ok:

We have the standard guard the controls on approach SOP which seems reasonable to me.

More bafflingly there's a procedure somewhere - (deliberate vagueness),one of those preference SOP /non SOPs which even the most diligent organisations end up with - which calls for the pilot in the LHS when PNF to select speedbrake if requested by pilot in RHS, then keep hold of it to be reminded of its deployment, then re-stow it on request. The RHS PF can still select and re-stow it if he chooses, A/P in or out - it matters not, but the LHS guy is the one who should hold it whilst it's deployed.

I can see the reasoning given the standard position of the speedbrake lever, instances of brakes being left out, possibly 3 primary control lever groups to be manipulated together (wheel, thrust levers, brakes) - and maybe other things, but it's too close to Captain's hand hovering for my liking. Few day to day scenes rival that for hacking people off.

Willfly380... Look at your own handle and you know you're not right... Even in the soon-to-be most modern airliner in the world, the A380, I still see a cockpit with nice seats for real human beings.

P77

NO SOP on guarding the Parking Brake at FL 370.
Sorry its late,buenoches.

M.85

guarding controls whilst on a/p
 

Our company S.O.P.s state" whilst below msa" a/p to be guarded.Hand flying is not encouraged at all,hence erosion of flying skills,Seen it too many times,A/P disengaged by enthusiastic rt. seat,A/C all over the sky.!,in fairness,cant really blame anyone,company wants automatics,especially on SIX sector days,your are too knackered to "pole" the a/c.

If you are puzzled by the requirement to guard the thrust levers and control wheel during flight below 2500', or whatever, do a search for the A300 departure accident at Bucharest, some years ago. Better still, view the AA training video which covers this particular accident and then see if it makes sense.:(
By all means have faith in the quality of the systems in use but bear in mind that perfection is a VERY elusive quality.:sad:
It is still a truism - "NEVER ASSUME, CHECK"

Cornish Jack the Trarom A310 accident in Bucharest does not clearly support the argument for guarding thrust levers. In the accident one of the thrust levers stuck at TO thrust whilst the other retarded; what the crew failed to do was monitor the system / aircraft and disconnect the automation with a deteriorating situation. Thus as you state never assume always check, but checking does not necessarily require physical hands on.

If you imply that guarding controls is lightly resting the hands on the controls / thrust levers, then there will be improved awareness from positional feedback, a form of monitoring (N/A A320 onwards). However, caution for those operators who have autopilots with very light overpower forces (no auto cut-out) as a heavy hand may restrict the auto control input, which could cause the trim to run with more serious consequences than would be caused by a random autopilot disconnect.

I am still puzzled by the number of SOPs that appear to originate from “that’s a good idea”; without any real understanding of the design / certification principles. How many SOPs are backed up with a written explanation of ‘why’ and thus justify the management of perceived risk against higher workload or increased complexity.

Why would discretion’s company use m.s.a as a start monitoring altitude; good altitude awareness (that’s a good idea), but not entirely ‘Standard’ as in ‘SOP’. If your aircraft requires that you guard the controls so diligently, then why not hand fly the aircraft; oh, you are tired, what happens on the sixth sector when the autos are on the MEL, will you really say ‘no thankyou’. As a professional pilot the operational authorities require (or falsely believe) that you and your crew are competent to fly within prescribed limits; what is ‘all over the sky’ to one pilot may be within acceptable safety limits to the industry, but to an inexperienced pilot, or you, it could be a valuable opportunity to improve. Not blaming you – just suggesting that all of us could occasionally rethink the safety strategy.

In the TAROM incident, if the operating pilot had kept his hands on the thrust levers (even lightly) he would have had to notice that one lever was retarding as the automatics tried to maintain total power during power reduction. That he also failed to monitor the attitude change doesn't alter the fact that the sensory input from the thrust levers would have alerted him to the need for intervention. He didn't and a lot of lives were lost .... UNNECESSARILY.

“if the operating pilot had kept his hands on the thrust levers (even lightly) he would have had to notice that one lever was retarding”; quite true Cornish Jack, but alternatively how many operators require that all hands are off the thrust levers after the call of V1? A SOP supposedly to prevent inadvertent retardation after V1.

We cannot have it both ways (standardisation and improved safety) unless the relevant risks are evaluated and balanced before writing SOPs. What are the risks of an inadvertent thrust reduction after V1 with respect to a thrust lever jamming? No doubt, there are accidents in each category, but there should be solutions other than SOPs for hands on or hands off. Old-fashioned airmanship, knowledge, and discipline in obeying the meaning of V1 or by training improved engine instrument / controls / thrust lever scans may well have prevent these types of accident, but then we all know better because we think of a good idea for improving something and write a new SOP. Unfortunately, we don’t always think through all of the likely scenarios or we make too many assumptions about crew behaviours.

I think that we agree in our differences; by all means guard the controls, but do not be heavy handed with the SOPs.

I 'guard' the controls whenever I am operating in terminal areas. It gives good feedback as to what the autoflight system is doing and puts my fingers close to the disconnect switches. It also helps with remaining in the loop. As terminal areas are full of aircraft going every which way, you never know when you may have to manoeuvre in a hurry!