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SoundLesS
14th Jun 2007, 22:16
Hello

I have the a320 rating, and have seen the CBT for boeing at the school. There you can select which bank angle the AP should turn with.

Then I realised that i do not know what bank angle the airbus is turning with. Is it rate 1 turns or?

I wonder because I can remember that in 8168 it says that you shall maximum use 20 degrees of bank angle in circlings....and since the rate 1 turn is most like above 20 degrees, if the Vapp is around 140, then u exceed what is allowed...

So. Does anybody have a sollution on my problem ;)?

Thanks

Back Seat Driver
15th Jun 2007, 05:36
Control Roll Limit
During selected headingmode, the flight guidance part of the computer
imposes the roll limits.
During managed heading mode, the flight management part of the
computer imposes the roll limits based on true airspeed and the active
segment of the active leg, depending on the need for simple turn control
(the path over the ground is not fixed) or fixed path control (a defined
path over the ground).
For simple turn control (while turning to a heading target) roll limit 2
is imposed.
Roll Limit 2 between approx. 1oo - 330 knots TAS = 25deg AOB modified downward for lesser arc of turn.

Dream Land
15th Jun 2007, 07:09
Impressive information, would like to know where you obtained it, I remember inching heavy aircraft up to altitude only to get an assigned heading, old software commanded a 25 degree turn, sometimes killing what little lift we had. :*

SoundLesS
15th Jun 2007, 10:04
Hmm, as far as I remember I have not found anything about it in all the 4 FCOM's. Where do you have that information?

FlightDetent
15th Jun 2007, 13:33
BSD: I'd also appreciate the source of your info so that I can order the book afterwards! :D

CW / Dan: I swear I stumbled over this by pure coincidence but you may also find intresting FCOM 4.04.30 p10 Engine Out / Flight Guidance.

happy managing,
FD (the un-real)

Back Seat Driver
15th Jun 2007, 14:10
Honeywell FMS Pilots Guide

FlightDetent
15th Jun 2007, 14:35
:ok:

BANK ANGLE LIMITS
The bank angle limits, roll limit 1, and roll limit 2 are defined by the roll limit graph shown in Figure 5-3 and are based on true airspeed. During
an engine out condition, both limits are set at 15. - this does not contradict FCOM 4 I referenced, does it?


Control Roll Limit
During selected headingmode, the flight guidance part of the computer
imposes the roll limits. During managed heading mode, the flight management part of the computer imposes the roll limits based on true airspeed and the active segment of the active leg, depending on the need for simple turn control (the path over the ground is not fixed) or fixed path control (a defined
path over the ground).

-For simple turn control (while turning to a heading target) roll limit 2
is imposed.
- For fixed path control (in legs to capture a path) the FMS uses either
roll limit 1 or roll limit 2 as required below:
— Roll limit 1 - When the turn does not result in a captured and engaged leg.
— Roll limit 2 - When flying an arc to capture and engage a leg
- When flying an arc to a fix unless:
- The active leg is a holding pattern or procedure turn when roll limit 2 is imposed.
- The aircraft is within lateral overshoot navigation limits, (then the en route roll limit is 15), except in the terminal area where roll limit 2 is imposed.

NOTE: Below 700 ft radio altitude, when in LAND track and LOC track, bank angle is further limited to 10 by the flight guidance function.

ROLL LIMIT SUMMARY
Roll limit 1 is used for most straight line segments of a flight leg, and by
the FMS when the heading is managed. Roll limit 2 is used by the FMS on most managed transitions in the terminal area, and for specific procedures such as holding patterns, procedure turns, and arcs.

http://img264.imageshack.us/img264/9408/fms320rolllimitdb8.th.gif (http://img264.imageshack.us/my.php?image=fms320rolllimitdb8.gif)


FD
(the un-real)

FlightDetent
15th Jun 2007, 14:42
CW: As far as I remember, 8168 designes protection areas on
rate 1 turn
or turn with 25 deg bank
whichever requires less bank

The obvious killer is when you attempt to fly a procedure above its max designed speed so that 25 deg limited turn becomes wider than calculated. Can you check the Doc if I am correct or not?

SoundLesS
15th Jun 2007, 21:24
Yes you are correct. Its what the doc uses normally. But in circling its a little bit different.

Radius arc of protected area is :

bla bla bla ....

bank angle : 20 degress or 3 degrees/sec, whichever requires less bank.

Anyway with Airbus I can conclude its up to the FMGC and in boeing its up to the pilot? =)

This leads me to another question. Do you as a boeing pilot use this bank angle settings??? Do you change to other angles than 25???

Back Seat Driver
16th Jun 2007, 02:15
..Diverting around wx in a 744 at heavy weight, near to or at max. Alt...ABSOLUTELY (10 degree bank limit works well)

Dan Winterland
16th Jun 2007, 02:34
"and in the Boeing, it's up to the pilot'.

Depends on the Boeing and the SOPs. The bank angle selector has an Auto position in some types. The company SOPs for a previous employer had it left in Auto.

alexban
16th Jun 2007, 18:21
Flying in LNAV , a 737 will bank with max AOB of 23 deg, or half the difference to the new heading ,if less.
In HDG SEL we tend to use 15 deg in high cruise flight and at take-off (for an engine failure less or close to V2 ) ,20 or 25 at low altitudes and in WXR avoiding. 30 deg only if necessary in WXR avoidance or LOC capture vectors.

FlightDetent
18th Jun 2007, 11:06
I wonder because I can remember that in 8168 it says that you shall maximum use 20 degrees of bank angle in circlings....and since the rate 1 turn is most like above 20 degrees, if the Vapp is around 140, then u exceed what is allowed...

The answer is no, you wouldn't. As you say , circling protective area is calculated to accomodate turns as shallow as 20 at max speed for the given category. If you do a 25 turn, it comes out tighter. If you did a 10 manouvre over 20 protective area, that is where you find yourself outside the protected airspace.

SoundLesS
18th Jun 2007, 16:12
Yeah you are so right... ;) thank u

cqx1223
25th Mar 2009, 05:27
I have the same question,
I've started flying an A330 in my FS, the problem is,
the turning rate is about 0.6 degrees per second............extremely slow.......the plane can't even make a sufficient turn to the next leg of the flight.....
But it turns with a normal 3 degree/S rate under the HDG mode............strange
Can someone help me?


Thanks!

AF024
22nd Jun 2009, 18:35
Hi everyone,

For my curiosity, I'd like to know what they means by "Roll limit 1 - When the turn does not result in a captured and engaged leg" ?
Can someone give me an example ? Thank's.

OPEN DES
22nd Jun 2009, 19:17
Roll limit 1 - When the turn does not result in a captured and engaged leg

My understanding is that it basically means that the aircraft will fly up to 30 deg bank in NAV mode whenever you are overshooting the turn (calculated green line).