Take Off N1 Thrust question

[Thomas Richter]

The major problem of all is a known behave of pmMCP that has to be corrected. It is on Enrico's todo list.
It means A/T works Okay and fast, but in ToGa/N1 mode it increases to slow. Normally you should get the power in oround 2 seconds, but actual it takes much longer but will be corrected.

Also there are sometimes different checklists from company to company and A/C's and engines. So if you have different engines in the same A/C type the handle can be different because the manufacturer gives the line.

e.g. in a CRJ
- center the A/C on RWY
- depress toe brakes
- increase N1 up to minimum of 50%
- hold toe brakes depressed for 30 seconds minimum to stabilize N1
then go

But in any case the different engine parameters gives you the GO when they are Okay, like EGT; N1/N2, Vibration ...
There are also some other factors to use ToGa or NOT, e.g. with strong tail wind you don't use ToGa because it doesn't work correct ....

[eudoniga]

I once heard a 737 pilot saying he'd use some pedal brakes to keep the a/c steady during spool up, but never dare to use the p/b: if it remains locked for any unforeseen reason, you have temporary paralyzed that runway !

And if it's a single runway airport, you have temporary ... closed the airport !!!

[Thomas Richter]

I once heard a 737 pilot saying he'd use some pedal brakes to keep the a/c steady during spool up, but never dare to use the p/b: if it remains locked for any unforeseen reason, you have temporary paralyzed that runway !

And if it's a single runway airport, you have temporary ... closed the airport !!!

Like Pete described, Toe brake and Parkbrake is exactly the same !!
The difference is that the Parkprake is a mechanical blocking of the Toe brake pedals in there depressed position. So the Toe brakes are in both cases depressed.
If you enter a Cockpit with Parkbrake set, the Toe brakes are in depressed position because the Parkbrake Lever blocks "only" the pedals in depressed position.
To unlock it is NOT possible to release the Park brake Lever only !
You have to depress the Toe brakes full and then release the Parkbrake Lever.
It is not like in a car where you have two different brake systems. In A/C's there is only one.

To set the Parkbrake or only hold the Toe brakes depends on the roles of the company and the day-feeling of the Pilot. No one will notice what he did

[Peter Dowson]

Oh ja. Hopefully it is near the top of the list (Vers. 3.xx + 4.xx)

Well, it wasn't on at all till last night -- oddly no one had asked for it. It only occurred to me as I was writing to this Forum.

It should be easy enough. Flags someplace, like in offset 310A. Would it be okay if these are cleared after 10 secs if not replenished, like the others? pmSystems should be able to re-set the flags every second or two?

There will be a Byte somewhere with separate Left and Right Brake disconnect flags, and two 16-bit words containing the current axis input value. When intercepted pmSystems would have to read those and apply them at offsets 0BC4 and 0BC6, but in a weakened form depending on brake pressure availability.

I'll look at doing this before the next major release if you think you can make use of it?

Regards

Pete

[eudoniga]

the Parkprake is a mechanical blocking of the Toe brake pedals

In fact I guess he was referring to the ... blocker's block !!!

[Ray Proudfoot]

Hi Themis,

When you taxi you try to not speed up over 20knots Ground Speed. If you are close to manouvering areas (near airports buildings) you try to be at 10 knots . In real life I've seen taxi speed up to 40 knots when the Tower is not seeing you..

I stay within the speed limit when taxiing.... just. Some people are the aviation equivalent of Lewis Hamilton!

The N1 value on taxi is not something to be considered of. Depends on your weight. The 737 doesn't need huge amounts of thrust to taxi. Just an initial push...and it rolls and very easily a bit over idle.

The PMDG737 model that I use is very close to those values.

When you reach holding point if there is traffic you can use the parking brake to fully stop the aircraft and not applying toe brakes as you waiting for clearance.

That would be traffic on the active - not inbound.

In critical phases (holding point, line up) if you think that there is gonna be a delay before the clearance arrive, you can use parking brakes for safety that the aircraft would not "slip" on the runway. After you get the clearance and release the brakes you advance the throttles to taxi for line up and *when you feel comfotable* you advance the Throttles up to 40% N1 waiting for the engines to stabilize... then TOGA... autothrottle does the rest.

That's just what I was looking for. Brilliant! Thanks.

In short runways I'll use brakes at the stabilization period to gain some meters.

Roger!

Now that we've got a standard lne-up and take-off sorted what's the procedure for an immediate departure? Radar Contact v5 will feature this with inbounds a certain distance out. Obviously things are more time-critical. I'd be interested to know the procedure please.

[Tomlin]

Hi Ray

Also, if youre not already privy to it, here's an excellent source from the horse's mouth: http://www.smartcockpit.com/plane/boeing/B737/

[Ray Proudfoot]

Hi Ray

Also, if youre not already privy to it, here's an excellent source from the horse's mouth: http://www.smartcockpit.com/plane/boeing/B737/

Hi Eric,

Perhaps I'm a bit slow but I can't find anything there relating to an immediate departure clearance if that's the correct term to use.

I believe the word 'take-off" is only used when clearance is given to take-off. It's never used in any other instruction so as to avoid any misunderstanding.

I'm going out shortly but will return later tonight or later tomorrow after Pete D and I go on Concorde G-BOAC at Manchester (EGCC). Unfortunately it won't get airborne and even though I've never ben inside one I'm really looking forward to the trip.

Cheers.

[Peter Dowson]

Some people are the aviation equivalent of Lewis Hamilton!

Hey, I rarely do more than 35-40 on the straight! Except maybe in O'Hare when the really really long straights almost demand at least 50 -- and I'm sure I've seen them doing it for real too!

Pete

[themis]

Now that we've got a standard lne-up and take-off sorted what's the procedure for an immediate departure? Radar Contact v5 will feature this with inbounds a certain distance out. Obviously things are more time-critical. I'd be interested to know the procedure please.

The ATC asks you:"Are you ready for an immediate departure?"
You must have finish all the check lists (and BEFORE T/O) to be really ready.

Once you get the clearance...

From Holding Point you start entering the Main RWY by advancing the Throttle to 40%. Until you line up with the runway the engines should be stabilized. Then TOGA.

So the use of main runway is limited.

Themis