Ask The Pilot

[Skyhigh777]

How do aircraft stay in a straight line during takeoff? Do you steer using rudder input while at high speed on the ground?
Thanks

 

[jb747]

How do aircraft stay in a straight line during takeoff? Do you steer using rudder input while at high speed on the ground?
Thanks

You use the rudder pedals, never the tiller, when on the runway. The pedals have an interconnect to the nose gear steering, and give up to around 7º of nose gear movement in either direction (as opposed to 70º for the tiller). After approximately 60 knots the rudder will overpower the nose gear and it does most of the work from that point.

 

[D747]

You use the rudder pedals, never the tiller, when on the runway. The pedals have an interconnect to the nose gear steering, and give up to around 7º of nose gear movement in either direction (as opposed to 70º for the tiller). After approximately 60 knots the rudder will overpower the nose gear and it does most of the work from that point.

JB a couple of follow up questions; What is used when exiting the runway? Is 7º enough for a high speed turn-off? What speed is a high speed turn-off taken at? At what speed does the transition from rudder to tiller happen? Is there a speed call out by the PNF to indicate that the tiller is now available?

 

[jb747]

What is used when exiting the runway?

Normally the tiller.

Is 7º enough for a high speed turn-off?

It will get you started, but you'll need to transition to the tiller. 7º is enough to keep you straight. Useless for most turns.

What speed is a high speed turn-off taken at?

In theory up to 50 knots. In reality, that's asking to end up in the grass. Mostly about 30 knots.

At what speed does the transition from rudder to tiller happen?

When you reach normal taxi speed. 30 knots. It generally coincides with reverse being cancelled. You simply use whatever you need.

Is there a speed call out by the PNF to indicate that the tiller is now available?

Not specifically. It really isn't that important that it should be called.

 

[Saab34]

JB have you operated the super into Europe in this type of weather they are experiencing?

I noted yesterday one of the A380s on late final was at 95kn ground speed. What are some of the challenges with such a ground speed?

 

[jb747]

JB have you operated the super into Europe in this type of weather they are experiencing?

380 and 747. My only European diversion was in a 747 in similar weather. It was outside of the wet runway crosswind limits, though we had a look down to a couple of hundred feet. There were no issues in the 380 in conditions similar to this. I haven’t seen anything really outlandish in the current Heathrow reports…pretty much normal to hit similar conditions at this time of year.

I noted yesterday one of the A380s on late final was at 95kn ground speed. What are some of the challenges with such a ground speed?

The 380 is always flown with the autothrust active (unless you’re an idiot) and its response in these conditions is very rapid. I was told numerous times by ex 330 FOs that it was a million percent better than the 330. And it was also much better than the 747/767.

The normal 380 approach speed is about 135 knots (so quite a bit slower than the Boeings). The target speed is increased in windy conditions, and then it dynamically increments with the gusts, so that there’s always an energy margin. We did similar in the 747 by calculating a minimum groundspeed. With a headwind, the sink rate is lower (normally about 700 rpm, but I guess about 450 in this case), and the base power is higher, but the picture looks the same. You need to ensure that you don’t run out of energy in the flare, so you might ignore the Frenchman’s calls of ‘retard’ for a couple of seconds.

The gusty crosswind component is less of an issue in the 380 than it was in the 747, because the FBW saw the such crosswind changes as sideslip. It hates that, and is very quick to apply rudder (the lower part of the rudder only) to correct it. That has the effect of removing about half of the issue with crosswind changes. You can pick the pilot rudder inputs, as they move the entire rudder. The only negative of the 380 vs the 747 in these conditions was that you had to get the drift below 5º at touchdown, whereas the Boeing didn’t care.

 

[Flashback]

JB have you operated the super into Europe in this type of weather they are experiencing?

I noted yesterday one of the A380s on late final was at 95kn ground speed. What are some of the challenges with such a ground speed?

I have some great videos from Friday at LHR.

 

[ayebee]

Question for the A380 experts ...

I had not noticed before, but I see Qantas' VH-OQB operating the SYD-LAX-SYD service has 3 lights illuminating the left wing / engines, but not the same on the right side.
Is this a safety thing (eg for illuminating airbridge status) or is it similar to the image lighting of the tail etc ?

 

[Flashback]

What happens to planes when there is wind? I have a good video.

 

[jb747]

Question for the A380 experts ...

I had not noticed before, but I see Qantas' VH-OQB operating the SYD-LAX-SYD service has 3 lights illuminating the left wing / engines, but not the same on the right side.
Is this a safety thing (eg for illuminating airbridge status) or is it similar to the image lighting of the tail etc ?

Where did you see that? I don’t recall any asymmetric lighting. If you can point me at your source, I’ll have a look at the manual when I get home in a few days.

There is wing/engine lighting, but it’s on both sides. Mainly it’s meant for the pilots, so that we can look at the upper surface of the wing for icing when on the ground.

Post automatically merged: Feb 20, 2022

What happens to planes when there is wind? I have a good video.

And your question for this thread?

 

[ayebee]

Where did you see that? I don’t recall any asymmetric lighting. If you can point me at your source, I’ll have a look at the manual when I get home in a few days.

There is wing/engine lighting, but it’s on both sides. Mainly it’s meant for the pilots, so that we can look at the upper surface of the wing for icing when on the ground.

yesterday's live stream replay

QF12 pushed back @ 10:42:00 on the video.
Taxiing around 10:51:00 - front on view shows left wing more lit than right, then both sides visible with taxi & takeoff.

 

[Carrots]

I'm thinking that might just be light reflecting back off the fuselage on to the flappy bits. (I might hide from JB now due to my lack of correct terminology).

 

[jb747]

Ok. You’re looking at a couple of things. The wing lighting is on both sides. The taxiway turnoff lights come on and off a few times, so sometimes you see three lights in a triangle, and at others two. They can also be very annoying for others, so you might have them on on the side away from the runway. If you look at airliners.net, you’ll see all sorts of variations. But, the overall light installation is symmetrical.

 

[Saab34]

AV, what exactly are you guys up to during that 30 or so minute turnaround in the coughpit? I always see pilots shuffling paperwork, on the phone, working our calculations, always wondered what exact jobs you are up to?

JB, in Pilot land is it a ‘coughpit’ or ‘flightdeck’. And are Pilots ‘Pilots’ or ‘Flight Crew’

 

[jb747]

AV, what exactly are you guys up to during that 30 or so minute turnaround in the coughpit? I always see pilots shuffling paperwork, on the phone, working our calculations, always wondered what exact jobs you are up to?

When I get home I’ll see it I can upload a pdf of the 380 preflight. That will keep you amused for hours.

JB, in Pilot land is it a ‘coughpit’ or ‘flightdeck’. And are Pilots ‘Pilots’ or ‘Flight Crew’

Pilots. coughpit.

 

[ayebee]

Ok. You’re looking at a couple of things. The wing lighting is on both sides. The taxiway turnoff lights come on and off a few times, so sometimes you see three lights in a triangle, and at others two. They can also be very annoying for others, so you might have them on on the side away from the runway. If you look at airliners.net, you’ll see all sorts of variations. But, the overall light installation is symmetrical.

Thanks for the explanation.
I had not realised aircraft had taxiway turn lights.

 

[Saab34]

When I get home I’ll see it I can upload a pdf of the 380 preflight. That will keep you amused for hours.

That would be great even PM me if not wanting to upload I will probably spend all day looking at it.

 

[Fergo747]

In theory up to 50 knots. In reality, that's asking to end up in the grass. Mostly about 30 knots.

When you reach normal taxi speed. 30 knots. It generally coincides with reverse being cancelled. You simply use whatever you need.

Jb, does that mean that a 'high speed' turn-off is somewhat of a misnomer?

If I am interpreting what you've written correctly, you would generally exit at a high speed turn at 30 knots (not 50 knots unless you want to end up in the grass) and you transition to tiller at 'normal' taxi speed of 30 knots - therefore meaning that a 'high speed' turn-off is effectively at normal taxi speed?

 

[MEL_Traveller]

yesterday's live stream replay

QF12 pushed back @ 10:42:00 on the video.
Taxiing around 10:51:00 - front on view shows left wing more lit than right, then both sides visible with taxi & takeoff.

It doesn’t look like QF has its cabin lights dimmed for takeoff?

Seems an equal mix of airlines that do, and don’t, have their cabin lights dimmed for takeoff and landing.

 

[eric2011]

When you reach normal taxi speed. 30 knots. It generally coincides with reverse being cancelled. You simply use whatever you need.

Landed on QF BNE 01L and exited the runway very quickly yesterday and reverse wasnt cancelled until about 100 meters down the taxiway. Mind you the new runways and taxiways are very spacious on the new runway, but we were doing more than 30knots