Ask The Pilot

[markis10]

I believe the B744 (and most likely other A/C) has 3 radios (ignoring things such as HF radios, and I can't remember if the 3 are UHF or VHF). L - C - R. Would it be an accurate assumption that the pilot tunes in on the L radio, the co-pilot tunes in on the R radio and the C radio is tuned into the emergency channel?

Also if for instance, both pilots decide to use the L radio, would changing the frequency on the pilots side mean that the frequency displayed on the radio on the co-pilots side automatically update with the new frequency? Also would both displays show the same standby frequency or could both pilots be using radio L, but each one has a different standby frequency at the ready?

Civil aircraft use VHF, while military use UHF amongst other things!

Checkmate JB747 - Stud One, check wheels

 

[albatross710]

Checkmate JB747 - Stud One, check wheels

[long pause as wheels extended]


"Beep"

 

[markis10]

[long pause as wheels extended]


"Beep"

It was a spoken beep when the check wheels was given to a Roller!

 

[Boris spatsky]

It was a spoken beep when the check wheels was given to a Roller!

And never a good thing when one did this on the next aircraft type, that was actually fitted with it

 

[mannej]

Sounds like wake. There's a video of an encounter in my youtube stuff.

I am aware of the AA587 crash whilst trying to overcome wake.

How much of a concern is wake, and what are the variables in relation to the severity of wake?

 

[jb747]

I am aware of the AA587 crash whilst trying to overcome wake.

How much of a concern is wake, and what are the variables in relation to the severity of wake?

Wake is a relatively minor concern as far as large aircraft are concerned. Yes, if you get too close it can thump you around, and the rolling motions can be quite strong, but generally they are easily handled by normal control inputs. ATC use differing standards to separate aircraft (i.e. big aircraft can be closer behind smaller aircraft than the other way around) to help minimise wake issues. The 380 is very large, displaces a lot of air, and others are generally kept well clear. The 757 has reputation for producing stronger wake turbulence than would be expected just by considering its weight.

AA587 was not caused by a wake encounter. It was caused by the same thing that killed AF447. Inept piloting coupled with some pretty poor engineering from the manufacturer. When the aircraft encountered the wake, all that was needed was appropriate aileron/spoiler inputs to counter any roll. Rudder should not have been used at all. In particular, the cycling of the rudder from side to side was the direct cause of the fin failure. The poor engineering comes into play as the forces required to move the rudder did not increase proportionally, but past a certain point, it basically just took pedal movement, not extra force to continue the motion. In any of these aircraft, the rudder pedals are basically just footrests, and should only come into play after an engine failure, or when flaring with a crosswind.

The National Transportation Safety Board (NTSB) concluded that the enormous stress on the rudder was due to the first officer's "unnecessary and excessive" rudder inputs, and not the wake turbulence caused by the 747. The NTSB further stated "if the first officer had stopped making additional inputs, the aircraft would have stabilized"

NTSB-American Airlines Flight 587 - YouTube

 

[jukebox333]

AA587 always seemed to me to be an unusual incident, JB - in that a plane falling apart during flight - other than due to sabotage, or maintenance error - is a rare event this far along in the jet age.

Until your coment about the pilot (above), I too, had assumed from the reports I read, that it was wake turbulence alone that was the direct cause of the failure.

On Googling the flight, I came upon This item. It suggests that the pilot, rightly or wrongly, may have been following AA training advice in acting the way he did.

Whilst I don't disagree that the engineering - and structural strength/safety factors in particular - appears to have been nowhere near conservative enough, if extreme rudder inputs was an AA sanctioned flying technique, isn't the airline the issue, not the pilot? Or, put another way, as a QF pilot, who it's safe to assume has not been advised to oscillate the rudder in such a situation, would it have crossed your mind that such an action could lead to catastrophic structural failure?

N.B. I can see I may not have made myself terribly clear here. I'm not try to absolve or pin blame on anyone with respect to this event - I don;t blieve that any pilot knowingly takes a course of action that will bring down an aircraft - but I'm curious if the extreme outcome of this sort of piloting had been even contemplated as a possibility prior to AA587.

*snip*
AA587 was not caused by a wake encounter. It was caused by the same thing that killed AF447. Inept piloting coupled with some pretty poor engineering from the manufacturer. When the aircraft encountered the wake, all that was needed was appropriate aileron/spoiler inputs to counter any roll. Rudder should not have been used at all. In particular, the cycling of the rudder from side to side was the direct cause of the fin failure. The poor engineering comes into play as the forces required to move the rudder did not increase proportionally, but past a certain point, it basically just took pedal movement, not extra force to continue the motion. In any of these aircraft, the rudder pedals are basically just footrests, and should only come into play after an engine failure, or when flaring with a crosswind.


[/FONT][/COLOR]
NTSB-American Airlines Flight 587 - YouTube

 

[harvyk]

A
On Googling the flight, I came upon This item. It suggests that the pilot, rightly or wrongly, may have been following AA training advice in acting the way he did.

From what I have heard the pilot was simply following AA SOP... I do also believe that the AA SOP was changed soon after this accident.
I don't know why alternating rudder inputs was ever considered a good idea, as to me it would seem like a really good way of losing control of an aircraft very quickly, unless you managed to sequence the inputs perfectly.

On a slightly different note, and more back on topic, if a pilot declares a mayday, can they undeclare it? Is there ever likely to be a situation where a mayday is called and then retracted before an A/C gets onto the ground? or is it considered if something was serious enough to warrant a mayday call, it's serious enough to not be considered over until the aircraft is back on the ground?

 

[jb747]

AA587 always seemed to me to be an unusual incident, JB - in that a plane falling apart during flight - other than due to sabotage, or maintenance error - is a rare event this far along in the jet age.

Until your coment about the pilot (above), I too, had assumed from the reports I read, that it was wake turbulence alone that was the direct cause of the failure.

On Googling the flight, I came upon This item. It suggests that the pilot, rightly or wrongly, may have been following AA training advice in acting the way he did.

Whilst I don't disagree that the engineering - and structural strength/safety factors in particular - appears to have been nowhere near conservative enough, if extreme rudder inputs was an AA sanctioned flying technique, isn't the airline the issue, not the pilot? Or, put another way, as a QF pilot, who it's safe to assume has not been advised to oscillate the rudder in such a situation, would it have crossed your mind that such an action could lead to catastrophic structural failure?

N.B. I can see I may not have made myself terribly clear here. I'm not try to absolve or pin blame on anyone with respect to this event - I don;t blieve that any pilot knowingly takes a course of action that will bring down an aircraft - but I'm curious if the extreme outcome of this sort of piloting had been even contemplated as a possibility prior to AA587.

I'm surprised that anyone would even attempt to use the rudder to correct roll in almost any aircraft. Roll, is after all, a secondary effect, and you have a primary control dedicated to it.

Were people aware that you could break the aircraft? I think they were. I suspect the issue is not awareness, but more the fact that it was so easy, and that's where the force required to move the pedals becomes an issue. Rudders will be applied extremely forcefully, all the way to the stop if necessary to control the yaw from an engine failure. But there simply isn't a reason to cycle the rudder, or any other controls really. I have no doubt that similar rudder applications would break any airliner.

Rudder travel is restricted in most aircraft. As speed increases, the rudder travel can be limited in a number of ways.

The force per g discussion means that (for instance) it may take 20 lbs of force to move the rudder from neutral to the half way mark, and an extra 20 to get the rest of the way to the stops. But, in this aircraft, it apparently took no extra force, only pedal motion, to go the rest of the way. That meant that the actual position was almost certainly difficult to feel, especially in the case of rapid input(s).

The Macchi (and I guess many other aircraft) had a similar issue in pitch. It required a linear increase in force to go from 1g to about 6g, but little extra force was required to go above six....overstresses were easy to do.

 

[jb747]

On a slightly different note, and more back on topic, if a pilot declares a mayday, can they undeclare it? Is there ever likely to be a situation where a mayday is called and then retracted before an A/C gets onto the ground? or is it considered if something was serious enough to warrant a mayday call, it's serious enough to not be considered over until the aircraft is back on the ground?

Yes, though I certainly didn't.....

 

[harvyk]

Yes, though I certainly didn't.....

So what sort of situations may at first call mayday, but later retract that call?

 

[jb747]

So what sort of situations may at first call mayday, but later retract that call?

Harv, I'm sure your imagination is as good as mine.

 

[mannej]

Talking about plane changes (as per the 380 reconfig thread), how long before a flight do you become aware of what plane you are flying on.

Is it not something that you bother about?

 

[jb747]

Talking about plane changes (as per the 380 reconfig thread), how long before a flight do you become aware of what plane you are flying on.

Is it not something that you bother about?

On the 380 we get some information about the flight a few hours out. Load/registration/crew. But, realistically, it doesn't matter (nor did it on the 767 or 747).

 

[Must...Fly!]

I'm surprised that anyone would even attempt to use the rudder to correct roll in almost any aircraft. Roll, is after all, a secondary effect, and you have a primary control dedicated to it.

It's a constant surprise as to what people are taught compared to what is right/should be taught or what someone does under duress, in every industry and application. It is in my opinion something of critical importance to the aviation industry, where obviously you have many pilots, many aircraft, many airlines with differing safety cultures and on top of that, many flying schools in many different countries with many different opinions, rules, cultures and philosophies.

 

[mjt57]

JB, when the flight crew carries out check lists, in what form are they? If paper and someone has to tick off each item, does that mean that you'd have reams of paper on board to carry out these tasks?

 

[jb747]

Checklists come in various forms. On the 747/747, checklists that are used every day are printed on laminated sheets, plus the pre take off, and landing checklists are also on labels on the centre of the control yoke. Emergency checklists are in book form.

The A380s uses the ECAM and one of the forward screens. Items generally change colour as the aircraft detects they've been done, or as you tick them (there are a couple of buttons which serve the function of ticks). There is also a booklet, but that's only used in a couple of cases which also take away the ECAM.

In all of the aircraft some immediate action checklists are done from memory, but they are then checked from either paper or ECAM as soon as possible.

 

[straitman]

Civil aircraft use VHF, while military use UHF amongst other things!

Checkmate JB747 - Stud One, check wheels

[long pause as wheels extended]


"Beep"

A little OT but pertinent. Several years ago they discovered on the PC9 that the 'beep' was only checking that the wiring circuit to the beeper was complete and not that the wheels were down and locked.

A fairly quick fix but a little embarrassing after many years of service.

 

[mjt57]

The A380s uses the ECAM and one of the forward screens. Items generally change colour as the aircraft detects they've been done, or as you tick them (there are a couple of buttons which serve the function of ticks). .

Do any of these serve as criteria which have to be met before the 380's control systems will allow further progress?

As an aside, my wife's looking for flights LHR-JFK-LHR during our Big Trip so we can pop over to visit the kids. One of them is with Delta which is one of the few airlines that we can find that has flights to match our timetable. It's on a B767-400.

For a trans-Atlantic flight what's it like from a pax's perspective? Would it be one of the more modern ones?

Been looking at QF but can't find anything suitable. I'd like to do MEL-LHR-JFK-LAX-MEL via QF but it's difficult to find fares for one, and to find something to come in under budget. So, it may be MEL-LHR-MEL with QF and a quick dash across the pond via whoever we can get seats on.

 

[jb747]

Do any of these serve as criteria which have to be met before the 380's control systems will allow further progress?

i'm not sure that I quite understand what you are asking....

But, there seems to be a general belief that the aircraft is really 'smart', and so stops us from doing many things. Whilst it is true that the are automatic limits for aerodynamic items like angle of attack and bank or pitch, the aircraft systems generally just do what they're told...like any other aircraft. In some ways the aircraft is less automated than the two decade older 747-400. Even the flight control limiting disappears quite early in any failure sequence ( the reversions to alternate/ direct flight control laws).

As an aside, my wife's looking for flights LHR-JFK-LHR during our Big Trip so we can pop over to visit the kids. One of them is with Delta which is one of the few airlines that we can find that has flights to match our timetable. It's on a B767-400.

For a trans-Atlantic flight what's it like from a pax's perspective? Would it be one of the more modern ones?

i'd rather suspect that it's just like any other 767, but with a slightly bigger cabin, and 777 style coughpit.

Been looking at QF but can't find anything suitable. I'd like to do MEL-LHR-JFK-LAX-MEL via QF but it's difficult to find fares for one, and to find something to come in under budget. So, it may be MEL-LHR-MEL with QF and a quick dash across the pond via whoever we can get seats on.

I flew across the pond with one of the US carrier a few years ago. I found it appalling in almost every way...including a landing in NYC that was so long that stopping at the far end became an issue. If I were to do it again I think I'd give Icelandair a go...