737 Lining up- Question for DJ and QF crew

[-438]

I have never quite understood the mini back track either.

Delta T, when you wrote,
"At a guess, the reduction in the de-rate for take-off will burn more fuel than the fuel expended on the line up procedure you describe."

I'm not sure if I've understood your double negatives correctly. But wouldn't max grunt take off use less fuel than a de-rated take off?

[greenslopes]

But what I really love is ATC wait till the landing aircraft has landed and vacated and the advise..."line up-be ready immediate".....................Why don't they give clearance to line up behind more often and the crew lining up would not feel so under the pump to get into the air.
If you line up behind the landing you can do your little backtrack and not set anyone's bloodpressure rising.

Just a thought

[No Further Requirements]

greenslopes

Sometimes tower controllers are hesitant to line up aircraft if the airspace they are firing you into is black with aircraft. It's not a nice feeling to line up someone behind the landing, with someone on final, and go to Approach for departure instructions to which they answer 'call you back'. There's a lot more going on up in the tower than you realise sometimes, and it's not just about the aircraft you can see and hear in the immediate vicinity.

Cheers,

NFR.

[DeltaT]

I'm not sure if I've understood your double negatives correctly. But wouldn't max grunt take off use less fuel than a de-rated take off?

If that were true, why don't planes fly around full throttle all the time?
(granted the exception of Concorde)

[Icarus2001]

many of us will "swing" towards the threshold a little to increase the radius of turn to the lined-up position and reduce stress on the gear and wear on the inboard tyres.

A bit of a wider turn to line up with a micro "backtrack" is good sense to me

Capn Bloggs Can I suggest that you take out a piece of paper and DRAW what you are suggesting, it makes no sense. A "mini back track" DOES NOT "increase the radius of turn". Nor is it WIDER! The greatest RADIUS of turn is gained by turning right or left 90 degrees on to the runway. By backtracking slightly you increase the degrees to be turned through in the same available width of runway so as Capt claret says...

I can't see that a mini back track, followed by a turn of > 110 degrees can reduce tyre wear or undercarriage stresses, compared to a 90 degree turn.

The MORE degrees you turn the aircraft through THE MORE the inside bogey slows down or stops, INCREASING tyre wear!

If you have an issue lining up inside the allowance on runway 21 at Perth then I suggest you need to get out more.

By the way, does your company lineup procedure measure to the main wheels, nosewheel, pilot position or aircraft data plate back to the threshold?

[-438]

I am of the understanding that full rated take off and climb will use less fuel than de-rated takeoff and climb. The cruise is another story.
However I'm quite happy to be informed otherwise.
Any excuse not to de-rate.

[Capn Bloggs]

Icarus,

I suggest that you take out a piece of paper and DRAW what you are suggesting, it makes no sense.

As requested (inboard main wheel shown):

By the way, does your company lineup procedure measure to the main wheels, nosewheel, pilot position or aircraft data plate back to the threshold?

I have no idea what you are talking about. Lineup allowance is lineup allowance. How it is practically applied is irrelevant. If you don't know how it is measured, I suggest you get into the certification rules.

[Keg]

Bloggs, nice piccie. I should note that your piccie is not what I was asking about in the first instance. I can't possibly replicate your drawing but what I've observed most often is the aircraft following the guidance until the nosewheel is on the runway then doing a sharp (20 degrees or so) turn in the opposite direction to the take off direction and then doing a sharp (full lock) 110 degrees turn back the other way. I agree that the drawing you illustrate would enable less tyre scrub but that ain't what most of these guys are doing.

[hongkongfooey]

I am of the understanding that full rated take off and climb will use less fuel than de-rated takeoff and climb.

True, de-rate is about reducing engine wear, not fuel consumption

[DeltaT]

Only because it takes longer to get to cruise height.