Bank Angle and Rate of Climb with Seatbelt Sign Off

[Guest Tomlin]

Hello allOver the past month I have been flying the PMDG 737-800 exclusively. It is the reason that I changed from designing a 777 flight deck to a 737NG flight deck (among many other practical reasons. The 2nd flight deck project will be the 777!)Over the past month, I have flown the 737NG all over the country, to places Ive never flown to before in FS. I have been flying without a passenger load, just getting used to all the systems and flying the PMDG demonstrator only, as I want to get to know the plane properly before flying for 'Delta' (virtually). Now, I have always abhored the way that the FS modeling is done regarding heading changes when reaching waypoints, so I usually disconnect LNAV and use the bank limiter on the HDG bug, or turn by hand to keep a smooth, passenger friendly turn to the next waypoint. My question is this: When I've flown on flights in the past (most recently in July) I hardly ever notice turning left to right or vice versa and the same goes for climbs/dencents. Now granted, I do feel it, but Im guessing it's only because I have actually flown in real life, and some clues from FS helps too. So, to get to the question already! (1) What is the general rule of thumb for a rate of climb (the MAX) that most Captains will climb or decent BEFORE they determine it's neccesary to turn on the Seatbelt sign? This question assumes little to no turbulence. (2) Also, I assume that any turn beyond a bank limit of 10 degrees would be too uncomfortable for passengers up walking around. Same question, at what point would most captains decide to turn on the seatbelt sign when anticipating a waypoint turn?(I turn it on around 10 miles prior to reaching the TOD/Waypoint)thanks,

[Guest Popart]

Interesting...I want to know as well ;-)

[Guest Soulman]

Typically, on a clear day (i.e no turbulence), the captain will turn the seat sign to AUTO upon reaching 10000ft. In most countries, a limit of 250KIAS under 10000ft applies, after which the NG will accelerate to a speed of 290-300KIAS (unless ATC restrictions apply). With the higher airspeed, the angle of climb is less than that needed to maintain a climb at 250KIAS, hence the plane climbs at a gentler rate and the captain can turn the seat sign off.This is just a general case - if you want me to go into more detail I can.As for A/P turns (either LNAV or HDG SEL) you can change the bank angle. It ranges from 10 degrees to 30 degrees from memory. You will find it on the MCP on the HDG SEL knob. At the top left of the knob you will see 30, followed by 10 at the bottom left. Top right is 10, bottom right is 30. Clicking your mouse over the HDG SEL knob will change the HDG, but if you move the mouse further left or right (i.e not directly over the knob), you will find that you can change the bank angle (known as the bank limit selector).I'm at school at the moment, and I don't have access to all of my reference material. I suggest downloading and reading the document/manual entitled Automatic Flight Management Systems from the PMDG website.Hope this solves your problems! If not, let me know and I'll be able to have a look at my material.

[Guest B1900 Mech]

I think the bank angle selector only works with heading select mode, and in some installations, VOR mode.I have read that in LNAV, the aircraft will sometimes set off the GPWS bank limit warning! The real a/c is real rough in LNAV. So with the carts in the isles, it would be VS and heading select only I would assume?

[Guest yawdamper]

Yes, the bank angle selector only works in HDG SEL. LNAV won't care about it.Remember though that the only influence of a high bank angle are the higher G loads. Pax won't start to fall over at 30

[Guest LCPH2004]

Hello all, Just to add what I think to this thread; I would assume that it would only be at low altitute/low speeds that passengers/attendents standing would experience problems with bank angles. This is because at lower speeds, there would presumably be less negative vertical acceleration on your body [the force that keeps you in your seat when the aircraft is turning] and it would be more difficult to stand up. At high speed/high altitude, when turning this vertical acceleration is presumably much higher as there is greater forces involved at moving at speed. This would seem to concurr with my experience on airliners, as during cruise hardley any sensation of turning can be felt even when banking at 25 degrees, wheras when manuvering before landing this feeling is much more pronounced. Just my opinion, to my thinking it would agree with the law of physics, but there may be some sort of rule or factor on aircraft that makes this whole post a load of rubbish, so, what do you think?

[Wolfko 0]

As Adrian correctly stated, you won't feel a 30

[Guest Ruddman]

I might be wrong but I thought the FMC/Autopilot automatically reduced the bank angle at cruising altidude to the miniumum allowed.If you won't feel 30 plus degrees on bank even if its cooridnated, why do air force pilots wear G suits!

[Guest Tomlin]

Thanks for the responses. To the first responder: I know all about the Bank Limiter on the HDG bug, and everyone is correct-it has no effect over the LNAV function although I wonder why Boeing would have chosen to not have it work that way.To the others regarding banking at altitude: I too rarely ever notice that we are turning (when flying for real) but since Im a student pilot on hiatus, and a sim pilot, I guess Im just more aware of what the aircraft is doing since Im looking out the window more and listening to the powerplants. Regarding turning beuyond 30 degrees and wearing flight suits: There's a huge difference in banking 30 degrees at high speed then pulling back on the stick than just cruising along at .79 and easing into a coordinated turn.Any real life airline Captains/FO's here?

[Guest Soulman]

Glad it could help in some way, shape or form.As for my credibility - a very close relative is an F/O. His name starts with and also ends with 'D'. Just gotta slip an 'a' in there and you've got it... ;)

[Guest yawdamper]

" Any real life airline Captains/FO's here?"YuppRegarding G suits:during level flight, G forces increase with the square of the bank angle. ie at 60

[Guest sj3]

>Glad it could help in some way, shape or form.>>As for my credibility - a very close relative is an F/O. His>name starts with and also ends with 'D'. Just gotta slip an>'a' in there and you've got it... ;)Mr. Soulman:Please let us know your real name, in accordance with forum rules. If it is Soulman, please tell your dad, Mr. Zappa, that Sam said hi. Thanks.

[Guest Soulman]

Sam, my real name is Jeremy Soulsby.I live in Australia - quite a trip from KEWR!

[Guest Ruddman]

From 767 Captain:"The autopilot smoothly flies the turn and we have set our course toward 4540N. When in the navigational mode, the angle of bank used by the autopilot is a function of speed and altitude, and up here, near the performance ceiling, you don't want a large bank angle. The wing loses a bit of lift in a bank, or, rather, the lift vector changes from straight up to off-vertical. Since only the vertical component of lift tends to keep us at altitude, the horizontal component created by the bank angle is no longer of use to us, except to pull the airplane through the turn. The Flight Control Computers take all of this into account, and bank angles above around 20,000 feet are reduced. Up here, the FCC's are using less than five degrees of bank to make this 14-degree heading change. No whitecaps in the martinis in the back!"link:http://www.flightsim.com/cgi/kds?$=main/feature/argosy1.htm

[Guest PittsburghII]

Hi, Quick question: What does the AUTO setting for seatbelts do? I can easily understand OFF and ON (:-)), but I am not sure what AUTO does. Is that for the cabin crew to decide, or is it based on some measurements of aircraft movement?Thanks,BoazEKCH