News:

Precision Simulator update 10.174 (26 April 2024) is now available.
Navburo update 13 (23 November 2022) is now available.
NG FMC and More is released.

Main Menu

Newbie Questions

Started by Shiv Mathur, Sat, 20 Jun 2009 15:35

Shiv Mathur

Some of the regulars might wonder why, after being on the forum for some 10 years, I am posting newbie questions !

Well, I had hardly used PS1 for several years, but recently I got several chances to get into this.

It's pretty much as complete as I imagine PC's sim is.

So now I was inspired again to fire up PS1 !!

So my first newbie q is:
the flaps lever has 'gates' in flaps 20 and flaps 1, so you have to perform extra gymnastics to move the lever from these positions.
Why is this ?

Shiv

Peter Lang

Hi Shiv,

The manual says

it is to prevent inadvertent movement past these detents.

Hope this helps
Peter

Shiv Mathur

Greetings Peter,

I was just wondering WHY these detents are so important, as opposed to the other flap settings.

Flaps 20, okay maybe while landing you don't want to slip into flaps 5  ( !!)
But flaps 1 ??

Shiv

Peter Lang

Hi Shiv,

the only situation I can imagine is, that below FL 100 you normally have a speed limitation of 250 KIAS. But often the aircraft is too heavy to retract the flaps fully at this speed. (Vref 30 + 80 is 250 at about 350 tons GW.)

Is it possible that this gate also pretents you to move flap lever from "up" into "1" ?

For Flaps 1 a max. extraction speed of 280 KIAS is allowed. During cruise you may have a little bit more KIAS (from the point speed restriction is cancelled by ATC or at least above FL 100 up to ~ FL 350). If you accidentally extract the flaps with far more than 280 KIAS you will encounter some problems to retract folded or somehow damaged flaps.

This would be more reasonable for me.

Peter

Hardy Heinlin

#4
Good evening,

as far as I recall, it is recommended to not move the flap lever beyond 5 until the leading edge flaps have reached their final position. These are much slower (30 secs or so) than the trailing edge flaps which move with the leading edge flaps in the first few seconds.

Imagine you would have the trailing edge flaps at 30 while the leading edge are not yet at 5. The wing profile would not be optimal.

So, be sure, and wait. Hence, the gate. (No rhyme intended.)

Cheers,

|-|ardy

P.S.: The 20 gate is for quick TOGA retraction.

Shiv Mathur


Hardy Heinlin

I was just reminded that - vice versa – not the leading edge but the trailing edge flaps are the slow ones (in real life and in PS1).

Also, in normal conditions, the TE flaps won't move to unreasonable positions before the LE flaps have reached their respective positions.

So, skipping the gate 5 is not really dangerous. Anyway, gate 5 is probably a reminder that you have commanded a flap position which needs a long waiting time (before any further flap commands make sense).

I need to refresh my rusty memory when I get to this topic in my PSX programming (I'm somewhere else at the moment).

Cheers,

|-|ardy

Shiv Mathur

The gate is at flaps 1 but, right ? (http://www.meriweather.com/747/ped/flaps.html)

Anyway, not important. Please don't let me distract you from your programming schedule, otherwise a lot of people here are going to get very annoyed with me !

Cheers,
Shiv

Hardy Heinlin

No problem.

Yes, sorry, the gate is at 1, of course. (Heck, I painted and programmed* this very gate "1" only four weeks ago :-))

(Even though my typo, I meant the flaps movement away from 5).

Cheers,

|-|ardy


* Just the mechanics of the flap lever and the gate, not the electronics.

Tor

If it is anything like the 737...

The 737 has gates at flaps 1 and flaps 15 (single engine G/A and normal G/A flaps settings). The gates are there to prevent inadvertent flap retraction beyond G/A flap setting.

So for G/A from normal both engines operating with flaps 30 or 40, the lever will stop at the flaps 15 detent.

For one engine inoperative which is flow with flaps 15, the lever will stop at the flaps 1 detent.


I presume that it's the same with the 744, just flaps 1 and 20 instead of 1 and 15.