Ask The Pilot

[jb747]

Bird strikes

Just wondering how common less serious bird strikes are? I am thinking that a sparrow getting sucked through the engines of an A380 isn't going to do much damage in reality. Is that a misconception?

It will cause a fair bit of damage to the bird.

A christmas turkey would cause some issues. The vast majority of birds do very little.

Are we better at scaring birds away from airports?

I don't know that we have an 'scaring' programs at the airports. I'm not that convinced anyway. Birds on the ground don't cause any problems at all...

We hear about "every" fault on QF aircraft that cause a minuscule delay (intended hyperbole on my part) but I don't recall every hearing aout a QF bird strike issue. Makes me think they don't happen or they don't matter.

And almost every 'fault' that you hear about is either trivia, or misrepresented.

And perhaps even the media would tire of things if they started reporting bird strikes. I don't know the frequency, but common is probably as good a 'number' as any. In all of my flying, I must be into the hundreds by now. Without exception they've ruined the birds day, but in only one case when I've been flying, has the aircraft suffered any damage.

Obviously, if you hit a very large bird, or a very large number, they can do damage. But most cases leave no more than a smear of blood on the aircraft.

 

[Austman]

I think I've caught flights at CDG Terminal 1 where the aircraft didn't need a push/back or be towed from the terminal? You can see some planes parked on google maps (then move a bit north). One big disadvantage of a terminal like this is that it's difficult to expand.

 

[Boris spatsky]

Ask The Pilot

I think I've caught flights at CDG Terminal 1 where the aircraft didn't need a push/back or be towed? You can see some planes parked on google maps (then move a bit north). One big disadvantage of a terminal like this is that it's difficult to expand.

Pretty sure it was the same in Geneva in the 90s. Underground train to circular terminals, aircraft park side on, 2 jetbridges connect to front and back. Seemed to work ok.

 

[simongr]

It will cause a fair bit of damage to the bird.

A christmas turkey would cause some issues. The vast majority of birds do very little.

I don't know that we have an 'scaring' programs at the airports. I'm not that convinced anyway. Birds on the ground don't cause any problems at all...


And perhaps even the media would tire of things if they started reporting bird strikes. I don't know the frequency, but common is probably as good a 'number' as any. In all of my flying, I must be into the hundreds by now. Without exception they've ruined the birds day, but in only one case when I've been flying, has the aircraft suffered any damage.

Obviously, if you hit a very large bird, or a very large number, they can do damage. But most cases leave no more than a smear of blood on the aircraft.

Thanks Jb - kind of brings into question the obsessive FOD Plods we had at the end of Air Training Corps camps to ensure every skerrick was collected.

And almost every 'fault' that you hear about is either trivia, or misrepresented.

I certainly agree there!

 

[Flying Fox]

View attachment 13245

Do they simply jack up one end and all the passengers slide down into the aircraft?

 

[jb747]

Thanks Jb - kind of brings into question the obsessive FOD Plods we had at the end of Air Training Corps camps to ensure every skerrick was collected.

FOD is a somewhat different animal. A small piece of metal will be way more damaging than a small piece of bird.

 

[mjt57]

It will cause a fair bit of damage to the bird.

A christmas turkey would cause some issues.

Particularly the frozen variety...

What was the story recycled on aus.aviation way back when, about British Rail using the same gear as Boeing or whoever to test bird strikes and were wondering why a chook was smashing their windscreens...

 

[MEL_Traveller]

I agree, and things such as mobile lounges just add to the ground traffic that needs to be kept away from moving planes.

oh I don't know - the private car transfers at FRA work perfectly my driver was hooning along - he said the LH planes regularly exceed their max allowed taxi speed and so the limos do as well

 

[harvyk]

oh I don't know - the private car transfers at FRA work perfectly my driver was hooning along - he said the LH planes regularly exceed their max allowed taxi speed and so the limos do as well

That's makes for an interesting question, one would assume that should you break certain aviation laws you are liable to be fined? If so who pays the fine? The airline or the pilot who actually broke the law?

 

[wafliron]

Re: Now Boarding ... Chicken or Beef?

There are many, many reasons for an abort, not just engine issues. Ask for an engine failure with severe damage at V1 minus about 5 knots. Do it at max take off weight.

I asked the instructor if he could set this up for me during the sim session this morning, and told him it was a "recommendation" from a Qantas pilot I "knew". The instructor looked at me, laughed, and said "clearly he doesn't like you very much"

Anyway, for whatever reason, the instructor didn't actually set up this exact scenario. Instead he gave me a complete failure of the left outboard engine at 160 knots, which in this case was V1 + 10 knots (or about VR - 10 knots) with the "aircraft" configured at MTOW. It... did not end well.

But, in my defence, I was confused because I thought I was getting an aborted take-off, and also thought I'd get a "bang" (or similar) plus coughpit warnings when the engine "failed", neither of which happened (he explained the fact that the coughpit warnings are disabled during take-off afterwards - interesting). At least, that's my story - and I'm sticking to it!!

And for a real eye opener, ask for the same failure at 10 knots (i.e. as the power is being set).

Unfortunately we didn't have time to try this - I'm dying to know what is so eye-opening about it, can you fill me in? Does the big imbalance of thrust at low speed produce severe yaw?

On a completely different note to the above, the instructor turned off the yaw dampers for me at one point - wow, does that make things feel uncomfortable (perhaps just because I can't actually fly a plane?)! Have you even had to fly a big jet without yaw dampers?

Thanks again for you advice, too!

 

[markis10]

Re: Now Boarding ... Chicken or Beef?

I asked the instructor if he could set this up for me during the sim session this morning, and told him it was a "recommendation" from a Qantas pilot I "knew". The instructor looked at me, laughed, and said "clearly he doesn't like you very much"

Anyway, for whatever reason, the instructor didn't actually set up this exact scenario. Instead he gave me a complete failure of the left outboard engine at 160 knots, which in this case was V1 + 10 knots (or about VR - 10 knots) with the "aircraft" configured at MTOW. It... did not end well.

But, in my defence, I was confused because I thought I was getting an aborted take-off, and also thought I'd get a "bang" (or similar) plus coughpit warnings when the engine "failed", neither of which happened (he explained the fact that the coughpit warnings are disabled during take-off afterwards - interesting). At least, that's my story - and I'm sticking to it!!

Aviation history is littered with many disasters as a result of expectations not being met, and pilots ignoring clues!

 

[jb747]

Re: Now Boarding ... Chicken or Beef?

I asked the instructor if he could set this up for me during the sim session this morning, and told him it was a "recommendation" from a Qantas pilot I "knew". The instructor looked at me, laughed, and said "clearly he doesn't like you very much"

Not a case of liking...I just thought you'd like 'interesting'.

Anyway, for whatever reason, the instructor didn't actually set up this exact scenario. Instead he gave me a complete failure of the left outboard engine at 160 knots, which in this case was V1 + 10 knots (or about VR - 10 knots) with the "aircraft" configured at MTOW. It... did not end well.

In part, the reason I suggested V1 minus a small amount was because it was pretty unlikely that you'd react quickly enough to initiate the abort below V1. So, you'd either end up with the nasty scenario of an abort above V1, or else, if you realised, a continued take off from the lowest speed that option is available. A very large percentage of our practice happens a few knots either side of V1.

But, in my defence, I was confused because I thought I was getting an aborted take-off, and also thought I'd get a "bang" (or similar) plus coughpit warnings when the engine "failed", neither of which happened (he explained the fact that the coughpit warnings are disabled during take-off afterwards - interesting). At least, that's my story - and I'm sticking to it!!

The joys of the sim. You never actually know what you're going to get, and even when training a particular scenario, they'll slip in something different, just to make sure the decision making process isn't being pre ordained.

Warnings inhibit at differing times (speeds) during take off. Even fire warnings eventually are eventually included, with most becoming active again at about 400 feet. You basically don't have time to have a warning, look at it, decide what to do, and then act. The PNF may simply say engine problem...you don't analyse it, that call itself is enough. The world has to be broken down to black or white...go or no go. Most engine failure aborts are initiated because of the sudden yaw, without any warnings or calls other than 'stop'.

Unfortunately we didn't have time to try this - I'm dying to know what is so eye-opening about it, can you fill me in? Does the big imbalance of thrust at low speed produce severe yaw?

At low speed, the tail has no straightening effect at all. Full tiller, and differential braking will make no difference at all, and the aircraft will simply turn and depart the runway within seconds. To stop that, the response must be extremely aggressive and will use full application of just about every control. At high speeds, the yaw is generally controlled by application of about half rudder.

On a completely different note to the above, the instructor turned off the yaw dampers for me at one point - wow, does that make things feel uncomfortable (perhaps just because I can't actually fly a plane?)! Have you even had to fly a big jet without yaw dampers?

Yes, though not for a long time. Back in the A4 days, firing the cannon used to kick the damper out.

 

[jb747]

oh I don't know - the private car transfers at FRA work perfectly my driver was hooning along - he said the LH planes regularly exceed their max allowed taxi speed and so the limos do as well

I doubt that he'd have any idea how fast the aircraft are allowed to go...but I will admit that I've seen some particularly fast taxying from the local airline, and given that it was in close proximity to other aircraft, and resulted in said local actually infringing an ATC instruction that he was 'number 2' to a very large visitor, can only say that it was an extremely poor example of airmanship, and well below the standard I'd expected of them.

 

[jb747]

That's makes for an interesting question, one would assume that should you break certain aviation laws you are liable to be fined? If so who pays the fine? The airline or the pilot who actually broke the law?

It depends upon who initiates the action. Mobs like CASA can take all sorts of action against individual pilots. Airport based fines (i.e. noise in London) will be directed to the airline.

 

[MEL_Traveller]

I doubt that he'd have any idea how fast the aircraft are allowed to go...but I will admit that I've seen some particularly fast taxying from the local airline, and given that it was in close proximity to other aircraft, and resulted in said local actually infringing an ATC instruction that he was 'number 2' to a very large visitor, can only say that it was an extremely poor example of airmanship, and well below the standard I'd expected of them.

i wasn't paying too much attention but he was saying something like they're only supposed to go xx mile per hour but they (the locals) go faster and the drivers sometimes have to pile on the speed to make it safely in front. I had no reason to doubt him. I can quite easily see drivers discussing with each other how fast they and planes go, and it seems a natural question to ask.

 

[wafliron]

Re: Now Boarding ... Chicken or Beef?

Not a case of liking...I just thought you'd like 'interesting'.

Oh, I know, I just thought the instructor's reaction was funny. It was very interesting, and I did like it

In part, the reason I suggested V1 minus a small amount was because it was pretty unlikely that you'd react quickly enough to initiate the abort below V1. So, you'd either end up with the nasty scenario of an abort above V1, or else, if you realised, a continued take off from the lowest speed that option is available.

That is perhaps why the instructor didn't set it up exactly as per your suggestion. Either way, I agree - having now been able to observe what happens, I very much doubt I'd have been able to initiate an abort before V1 (in your suggested scenario), so it would have worked out the same way.

We didn't repeat the scenario with an outboard engine failure, but did with an inboard engine failure. That one worked out much better for myself and my virtual pax - but of course I was also "forewarned" of what was going to happen by that point. It was very interesting to see / feel the massive difference between an inboard and outboard failure!

A very large percentage of our practice happens a few knots either side of V1.

That gives me a lot of comfort, having now seen first hand how quickly things go pear-shaped!!

Warnings inhibit at differing times (speeds) during take off. Even fire warnings eventually are eventually included, with most becoming active again at about 400 feet. You basically don't have time to have a warning, look at it, decide what to do, and then act. The PNF may simply say engine problem...you don't analyse it, that call itself is enough. The world has to be broken down to black or white...go or no go. Most engine failure aborts are initiated because of the sudden yaw, without any warnings or calls other than 'stop'.

Which makes complete sense, of course - it just wasn't what I expected before-hand.

At low speed, the tail has no straightening effect at all. Full tiller, and differential braking will make no difference at all, and the aircraft will simply turn and depart the runway within seconds. To stop that, the response must be extremely aggressive and will use full application of just about every control. At high speeds, the yaw is generally controlled by application of about half rudder.

Yikes, wish I'd gotten to see that now. When you say "use full application of just about every control", does that include throttling down the two engines on the side opposite to the failure, whilst temporarily leaving the one good engine on the side with the failure throttled up?

Actually, this has reminded me of another question I was wondering about whilst in the sim: is there a reason that the throttles for all four engines aren't "linked" in some way, so you don't have to fiddle with the throttles to get exactly the same EPR from all four engines, with a way to un-link them when desired / required? Obviously it's not that hard to push all four "in sync", but I did find myself occasionally having to adjust one throttle that I'd pushed a fraction further / less far than the rest. Perhaps the answer is due to scenarios like the question in the previous paragraph - needing to be able to quickly adjust just some of the throttles, without futsing around to "unlink" them - but I'm curious.

 

[jb747]

Re: Now Boarding ... Chicken or Beef?

Yikes, wish I'd gotten to see that now. When you say "use full application of just about every control", does that include throttling down the two engines on the side opposite to the failure, whilst temporarily leaving the one good engine on the side with the failure throttled up?

No. Again, you don't have time to think it through. But, the thrust levers are literally smashed back to the closed position. It's a wonder we don't break them. I've always wondered if anyone has ever had their hand/finger caught in the machinery when that happens. Once closed the yawing stops, but you still need differential braking and steering to stop the departure from the runway. And, then, of course, you don't want to lose it the other way as those controls take effect.

Actually, this has reminded me of another question I was wondering about whilst in the sim: is there a reason that the throttles for all four engines aren't "linked" in some way, so you don't have to fiddle with the throttles to get exactly the same EPR from all four engines, with a way to un-link them when desired / required? Obviously it's not that hard to push all four "in sync", but I did find myself occasionally having to adjust one throttle that I'd pushed a fraction further / less far than the rest. Perhaps the answer is due to scenarios like the question in the previous paragraph - needing to be able to quickly adjust just some of the throttles, without futsing around to "unlink" them - but I'm curious.

That's actually a curious comment, as the thrust levers in the -400 are linked, but electronically. As long as they're fairly close to lined up, the engine FADECs will ensure that the thrust is matched. If I recall correctly, the slowest accelerating engine controlled the match on windup, the highest on the way down. The 767 didn't have FADEC, and the levers were sometimes quite staggered. If manually controlling the thrust, without the FACEC (EECs), then matching the power up is just something else that you have to do. I recall experimenting with the -400 on one occasion, and you could pull a single lever back an inch or so, the power would wind back, then it would decide it should be matched, and with the lever in the same position, would wind back to the same power as the other engines. If you pulled it back a bit more, it would go 'out of range' and would stop thrust matching, for that engine only. Quite a nice system.

 

[wafliron]

Re: Now Boarding ... Chicken or Beef?

No. Again, you don't have time to think it through. But, the thrust levers are literally smashed back to the closed position. It's a wonder we don't break them. I've always wondered if anyone has ever had their hand/finger caught in the machinery when that happens. Once closed the yawing stops, but you still need differential braking and steering to stop the departure from the runway. And, then, of course, you don't want to lose it the other way as those controls take effect.

They did feel pretty sturdy Thanks for the info - I reckon I'll go back and do another sim session at some point, so I'll have to ask for this scenario and see how little chance I have of controlling it!

That's actually a curious comment, as the thrust levers in the -400 are linked, but electronically. As long as they're fairly close to lined up, the engine FADECs will ensure that the thrust is matched. If I recall correctly, the slowest accelerating engine controlled the match on windup, the highest on the way down.

Hmm, that is strange, as I'm 100% positive that on several occasions we had different thrust from readings from one (or even two engines). I distinctly recall one instance, where the friend I did the session with was "flying" and had managed to set three of the four engines to 1.21 EPR, but left the left outboard was at 1.18 - I corrected it for him.

That said, in all the cases I'm talking about, the difference in thrust was only small (0.01 to 0.03 EPR), and was only that way for a short time before it was manually corrected. Do the FADECs maybe ignore very small differences? Or take a little bit of time to match the thrust, so we corrected it ourselves before the FADECs did it for us?

I recall experimenting with the -400 on one occasion, and you could pull a single lever back an inch or so, the power would wind back, then it would decide it should be matched, and with the lever in the same position, would wind back to the same power as the other engines. If you pulled it back a bit more, it would go 'out of range' and would stop thrust matching, for that engine only. Quite a nice system.

Is there a way to turn off the linking system if required? I don't know how often thi would be "required", but perhaps in an emergency situation? It's a vague memory, but I seem to recall reading about a 747 which experienced severe damage to its control surfaces and the pilots had to resort to using engine thrust differentials to maintain some degree of yaw and roll control. Or perhaps in that situation the thrust differences were so great that the "out of range" situation you describe kicked in.

 

[jb747]

Re: Now Boarding ... Chicken or Beef?

Hmm, that is strange, as I'm 100% positive that on several occasions we had different thrust from readings from one (or even two engines). I distinctly recall one instance, where the friend I did the session with was "flying" and had managed to set three of the four engines to 1.21 EPR, but left the left outboard was at 1.18 - I corrected it for him.

That said, in all the cases I'm talking about, the difference in thrust was only small (0.01 to 0.03 EPR), and was only that way for a short time before it was manually corrected. Do the FADECs maybe ignore very small differences? Or take a little bit of time to match the thrust, so we corrected it ourselves before the FADECs did it for us?

Those small differences are exactly what the FADECs would remove. Perhaps my hand was simply better calibrated.

Is there a way to turn off the linking system if required? I don't know how often thi would be "required", but perhaps in an emergency situation? It's a vague memory, but I seem to recall reading about a 747 which experienced severe damage to its control surfaces and the pilots had to resort to using engine thrust differentials to maintain some degree of yaw and roll control. Or perhaps in that situation the thrust differences were so great that the "out of range" situation you describe kicked in.

Just turn the EECs off. We did fly that way sometimes, but I'm not sure why the sim would have been set that way for your flight. Unless they had their own plans on making it fun for you.

Whilst everyone knows that the 380 and its ilk are FBW, they probably never knew that the -400 is, in a small way, also. At least the engines are. In older aircraft, there were linkages of some sort between thrust levers and engines. But, in the -400, the engines are computer controlled, and the thrust levers are simply one end of the computer control system. Back in the 200/300, thrust lever movement, especially when setting take off power, was done slowly and very steadily. Then engines did not like any sort of slamming, especially from low idle. The -400 conversion was quite an eye opener, as we'd simply push the power up a bit (15% or so) to make sure they were all happy, and then press the TO/GA switch, at which point the system would automatically advance the levers to take off power at a rate much, much faster than we'd ever use. It wasn't an issue, because the engines weren't being directly controlled by the lever position. That was simply setting a target, and the EECs would control the engines on the way to that target.

 

[wafliron]

Re: Now Boarding ... Chicken or Beef?

Those small differences are exactly what the FADECs would remove. Perhaps my hand was simply better calibrated.

Just turn the EECs off. We did fly that way sometimes, but I'm not sure why the sim would have been set that way for your flight. Unless they had their own plans on making it fun for you.

Perhaps it was calibrated that way... but I suspect your first suggestion is the correct one

Thanks again for answering all my questions JB, really appreciate it.