Chamonix From France, joined Mar 2011, 295 posts, RR: 1 Posted (1 year 5 months 3 weeks 4 days ago) and read 5491 times:
Why does the B739 still have trim wheels whilst the other Boeings have a lever?
Are there no picth trim switches on B739 yokes?
What are those odd looking 3 "toothpicks/fork-teeth" selectors on the B739 yokes.
Any reason why B787 has 1 lever for instead of 2 on the other Boeings?
Many thanks!
yeelep From United States of America, joined Apr 2011, 526 posts, RR: 0 Reply 1, posted (1 year 5 months 3 weeks 3 days 20 hours ago) and read 5453 times:
Quoting Chamonix (Thread starter): Why does the B739 still have trim wheels whilst the other Boeings have a lever?
Are there no picth trim switches on B739 yokes?
All 737's have a direct mechanical link from the trim wheels to the stabilizer jackscrew. The wheels are there to provide the means to physically move the stab. The 737 also has a electrically driven trim actuator controlled by trim switches on the outboard side of each control wheel. I assume the later model Boeing aircraft have multiple electrically driven systems for redundancy instead.
Quoting Chamonix (Thread starter): What are those odd looking 3 "toothpicks/fork-teeth" selectors on the B739 yokes.
Its a customer option, the altitude clearance reminder. Think of a combination lock that doesn't do anything.
Quoting Chamonix (Thread starter): Any reason why B787 has 1 lever for instead of 2 on the other Boeings?
From a quick look at some flight deck pictures, it looks like you may be mistaking the parking brake lever for the horizontal trim switches which appear to be the two black switches just inboard of that lever. Keep in mind that I have no knowledge of 787 systems, so I may be wrong.
David L From United Kingdom, joined May 1999, 9219 posts, RR: 42 Reply 3, posted (1 year 5 months 3 weeks 3 days 20 hours ago) and read 5431 times:
Quoting yeelep (Reply 1): I assume the later model Boeing aircraft have multiple electrically driven systems for redundancy instead.
I included the 738 to show that the trim wheels are not unique to the 739 but I came to the same conclusion that clean-sheet designs that came after the 737 didn't have the trim wheels. Unable to say why, I left it alone.
Quoting Chamonix (Thread starter): Any reason why B787 has 1 lever for instead of 2 on the other Boeings?
It's what yeelep said:
Quoting yeelep (Reply 1): From a quick look at some flight deck pictures, it looks like you may be mistaking the parking brake lever for the horizontal trim switches which appear to be the two black switches just inboard of that lever. Keep in mind that I have no knowledge of 787 systems, so I may be wrong.
Just aft of the captain's touchpad is a silver lever and a wide black switch. The lever is the parking brake, the wide black switch is really two switches side by side to control trim. The two red guarded switches just inboard of that are the stab trim cutouts.
Quoting yeelep (Reply 1): I assume the later model Boeing aircraft have multiple electrically driven systems for redundancy instead.
Yes. It's not always electric by there's always some kind of dual path control and actuation for redundancy.
Barney Captain From United States of America, joined Nov 2001, 749 posts, RR: 14 Reply 5, posted (1 year 5 months 3 weeks 1 day 12 hours ago) and read 5062 times:
Quoting David L (Reply 2): Its a customer option, the altitude clearance reminder.
Fairly certain their intended purpose is for the current flight number - not altitude clearance.
Barney Captain From United States of America, joined Nov 2001, 749 posts, RR: 14 Reply 8, posted (1 year 5 months 3 weeks 1 day ago) and read 4909 times:
Quoting David L (Reply 6): You might be right but, on the other hand and taking a variety of factors into consideration... it wasn't actually me who said it.
Sorry about that....not sure what happened.
Quoting oldtimer (Reply 7): Was always the altitude reminder on my 707, 727 and 737 courses.
Over 20 years flying Boeing's and I can honestly say, that's the first I've ever heard of this. Isn't that what the altitude window in MCP is for (or ALT Alerter going back to the classics)?
We are talking about the same thing right? The 3 digit numeric thumb wheels on the yoke?
oldtimer From United Kingdom, joined Aug 2006, 191 posts, RR: 1 Reply 9, posted (1 year 5 months 3 weeks 23 hours ago) and read 4886 times:
Quoting Barney Captain (Reply 8): We are talking about the same thing right? The 3 digit numeric thumb wheels on the yoke?
Yes, the same thing was fitted to BAC1-11 and again was used as altitude reminder. You have to remember this goes back to pre INS and GPS days, these early a/c had only an altitude hold, you climbed on a/p and trimmed out at requested level and selected Alt. hold. You are only a sprog young man, pilots had to really work for a living in those days
Barney Captain From United States of America, joined Nov 2001, 749 posts, RR: 14 Reply 10, posted (1 year 5 months 3 weeks 14 hours ago) and read 4775 times:
Quoting oldtimer (Reply 9): these early a/c had only an altitude hold, you climbed on a/p and trimmed out at requested level and selected Alt. hold.
True - just like we always did in the -200's. But we still had an Altitude Alerter for that purpose.
Quoting oldtimer (Reply 9): You are only a sprog young man, pilots had to really work for a living in those days
Awe shucks, and here I thought those 14 hour/12 leg days hand flying a Metroliner were all for fun
Chamonix From France, joined Mar 2011, 295 posts, RR: 1 Reply 12, posted (1 year 5 months 2 weeks 6 days 20 hours ago) and read 4610 times:
Amazing as ever,mandala499!
Never ever seen a Boeing w/o a ALT Pitch lever!
That is really weird!
So 767 does not have it,777 does,787 does not!
I can not figure out what that that tiny lever is behind the touchpad on the 787 next to Trim Tabs? http://cdn-www.airliners.net/aviation-photos/photos/3/5/1/1942153.jpg
Maybe someone has a better pic?
Then they did the 767-400ER and the levers disappeared from all versions of the 767 (not sure if by SB for the older models) and became the wide switches:
Interesting that they had the paddle CMD switches a la 747!
I guess they retrofitted the paddle switches to the button switches for the exBA 767-336s that went to Qantas... and also the PFD/EADI received the new format... whilst the BA one, stayed as it is!
CWS mode was always an option, therefore, some/most, prefer to blank it out.
Quoting Chamonix (Reply 16): Digressing onto the MD-11:Does it have 2 Flap selectors next to F/O?
It is remnant of the old days when slats and flaps were two separate levers... one of the reason is that, that was the norm in those days, and also for the crew to not make a mistake whether they're on a Slats equipped jet or not (DC-8s didn't have them, and some of the DC-9s didn't have them)... Here's a no-slat DC-9...
Chamonix From France, joined Mar 2011, 295 posts, RR: 1 Reply 18, posted (1 year 5 months 2 weeks 6 days 14 hours ago) and read 4523 times:
Spanair crash entirely forgot to engage Flaps/Slats for T/O.
Taken off with flaps at 0°.
==================
Which is better and easier to use:Levers or Wide Tabs?
tdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80 Reply 19, posted (1 year 5 months 2 weeks 6 days 12 hours ago) and read 4488 times:
Quoting Chamonix (Reply 18): Spanair crash entirely forgot to engage Flaps/Slats for T/O.
Taken off with flaps at 0°.
==================
Which is better and easier to use:Levers or Wide Tabs?
I'm not really following you here...the lever/switch/wheel discussion (so far) has been all about stabilizer trim. That had nothing to do with the Spanair crash. I'm not aware of any large jet that doesn't use some kind of lever for flaps.
PGNCS From United States of America, joined Apr 2007, 2516 posts, RR: 45 Reply 20, posted (1 year 5 months 2 weeks 3 days 8 hours ago) and read 4242 times:
Quoting oldtimer (Reply 7): Quoting Barney Captain (Reply 5):
Fairly certain their intended purpose is for the current flight number - not altitude clearance.
Was always the altitude reminder on my 707, 727 and 737 courses.
Oh yes, the REALLY old days before altitude alerters were required. (Don't feel bad, I remember them too!)
Quoting Barney Captain (Reply 8): Quoting oldtimer (Reply 7):
Was always the altitude reminder on my 707, 727 and 737 courses.
Over 20 years flying Boeing's and I can honestly say, that's the first I've ever heard of this. Isn't that what the altitude window in MCP is for (or ALT Alerter going back to the classics)?
We are talking about the same thing right? The 3 digit numeric thumb wheels on the yoke?
Ah, but not all B-727 and DC-9's (and I believe B-737's as well, but I don't recall flying one without it installed) originally came with altitude alerters, and many even came with the dreaded three-pointer altimeter! (And yes, you are talking about the same thing.)
Quoting Barney Captain (Reply 10): Quoting oldtimer (Reply 9):
these early a/c had only an altitude hold, you climbed on a/p and trimmed out at requested level and selected Alt. hold.
True - just like we always did in the -200's. But we still had an Altitude Alerter for that purpose.
Oh I hated that autopilot (SP-77, I believe) and remember it well.
Quoting mandala499 (Reply 17): Quoting Chamonix (Reply 15):
CWS/CMD have been blanked-out.
CWS mode was always an option, therefore, some/most, prefer to blank it out.
Yes, and even when installed few people bother with it as the Boeings in CWS are a pretty unharmonious and unpleasant experience.
Quoting Chamonix (Reply 18): Which is better and easier to use:Levers or Wide Tabs?
They aren't ever used in normal operation, and I don't think in my simulator experiences there is a particular advantage to either.
Quoting Chamonix (Reply 18):
Spanair crash entirely forgot to engage Flaps/Slats for T/O.
Taken off with flaps at 0°.
==================
Which is better and easier to use:Levers or Wide Tabs?
I'm confused. What does the Spanair accident have to do with stab trim switches?
mandala499 From Indonesia, joined Aug 2001, 6181 posts, RR: 74 Reply 21, posted (1 year 5 months 2 weeks 3 days 3 hours ago) and read 4194 times:
Quoting PGNCS (Reply 20): Oh I hated that autopilot (SP-77, I believe) and remember it well.
SP-77 Mode 1... Lovely piece of engineering ! We call it, the "kitchen stove".
It really is a "point and hold" kind of automation... not the "press and forget" types...
But then... it hand flies beautifully, who needs CWS? (Well, CWS for the roll, hand flying for pitch" )
*OK, I'm asking for you and Pihero to throw a rotted-away 732 AFM at me!*
Mandala499
When losing situational awareness, pray Cumulus Granitus isn't nearby !
PGNCS From United States of America, joined Apr 2007, 2516 posts, RR: 45 Reply 22, posted (1 year 5 months 2 weeks 2 days 8 hours ago) and read 4099 times:
Quoting mandala499 (Reply 21): SP-77 Mode 1... Lovely piece of engineering ! We call it, the "kitchen stove".
I laughed so hard I came out of Normal law!
Quoting mandala499 (Reply 21): It really is a "point and hold" kind of automation.
Wait! It's automation? Seriously?
Quoting mandala499 (Reply 21): But then... it hand flies beautifully, who needs CWS? (Well, CWS for the roll, hand flying for pitch" )
I will say that the 732 is nicer to hand fly than some other Boeings, still not nearly as nice as the 757 though. It's sure easy to land, too. It's kind of like flying a big Cessna only not nearly as comfortable, ergonomic, or automated!
Sorry, it's "non critical phase workload reducing apparatus"... Since it can be quite useless on critical phases!
When losing situational awareness, pray Cumulus Granitus isn't nearby !
25 PGNCS: OK, that's much better! I will certainly believe it's a NCPWRA (or a Kitchen Stove!) before I'll believe it's an autopilot!
26 francoflier: I still don't like Boeing dropping the trim wheel. There's nothing like the precision of a trim wheel when hand flying. Of course, we're not really su
27 PGNCS: There's also nothing like it for finger and knee injuries.
28 Pihero: especially when one had forgotten to retract the handle ! doesn't hold a candle to the best ever solution : The Tristar electric trim thumb wheel, se
29 tb727: Remember, it will whack you in the knee 3 times before you can say ouch!
30 Pihero: Must have been drinking more than usual, that dear man: The 727 has never been an easy airplane and in terms of control balance.... it wasn't there w
31 PGNCS: YOW! I just got knee pain thinking about it. What an awful artifact of aircraft design from the 1950s! Absolutely correct Pihero! Easily the best way
32 tdscanuck: The wheel hasn't been directly connected to the stab, at least on a Boeing, since at least the 757 (maybe the 747). On the 777 and 787 it isn't even
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