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Topic: Flight Director Preference: Needles Or Inverted V?
Username: DeltaGuy
Posted 2004-03-09 09:23:04 and read 5607 times.

Was wondering about individual pilot's preferences on Flight Directors. There's the needles, or the inverted V. (double bars sometimes, single cue, double cue?)

Anyone have a particular preference? I rather like the needles, like on the EADI on many 757's, 767's, 777 , MD, etc...just little magenta bars. I guess either takes getting used to. I've seen both on the 757 and soon, especially with American...is there a customer option? I know it's standard on the CRJ.

Interested to know Big grin
DeltaGuy

Topic: RE: Flight Director Preference: Needles Or Inverted V?
Username: Kalakaua
Posted 2004-03-09 10:26:07 and read 5531 times.

Needles.

FILLER

FILLER

Topic: RE: Flight Director Preference: Needles Or Inverted V?
Username: B747Skipper
Posted 2004-03-09 10:41:54 and read 5523 times.

Needles like you call it, real name is "dual cue" - is more accurate.
A small command change is not as easy to see on a "single cue" V bars...
xxx
Happy contrails  Smile
(s) Skipper

Topic: RE: Flight Director Preference: Needles Or Inverted V?
Username: SlamClick
Posted 2004-03-10 16:11:16 and read 5319 times.

While I flew the Collins-style "Howard Johnson roof" for many years I am more used to the Sperry-style dual needles now and I think I prefer them.

Especially on FBW Airbus. There is a little square on the PFD that is part of the "airplane" symbol over the horizon. With the needles centered up, on an ILS, for example, there is just one pixel of the background color showing at each corner of the square, behind the needles themselves. Talk about a precise display for pitch and roll! One pixel deviation and you can respond to it.

Since the FBW system is digital also, the plane's response is matched to the display. It is not "the Atari factor" we looked for trying to fly analog airplanes in digital simulators. It is the real digital thing.

Topic: RE: Flight Director Preference: Needles Or Inverted V?
Username: JBirdAV8r
Posted 2004-03-10 16:40:13 and read 5311 times.

Well, I've only flown dual-cue FD's in simulators, and they are great. I, however, used to be rather fond of the older "flying football". Whatever floats your boat, generally.

A lot of newer aircraft, I think, have menu options to switch between dual-cue and single-cue flight directors.

Topic: RE: Flight Director Preference: Needles Or Inverted V?
Username: 411A
Posted 2004-03-10 16:47:39 and read 5305 times.

The first 'flight director' was developed by Sperry in the early fifties, and it was called the 'Sperry zero reader'.
It was a customer option on the DC6 (as was a later Bendix unit), and was very uesful for low visibility approaches.
Sperry stuck with the 'cross bars' type of presentation on their later flight directors, while Collins developed the 'V' bar (actually inverted V) presentation.

Worked for one airline that had both types, in the fleet.
Some found it confusing, especially the younger guys.

Personally prefer the Sperry 'cross bars' presentation, as it is much more accurate for CAT II/III approaches, IMO.

Topic: RE: Flight Director Preference: Needles Or Inverted V?
Username: DeltaGuy
Posted 2004-03-10 18:26:10 and read 5289 times.

Thanks for all the good opinions guys  Big thumbs up

For me, I've grown accustomed to dual cue, just easier to work with I think. When I was in the MD-88 simulator, small pitch/roll change, you could see it. In the 732 sim, there's the inverted V (as Slamclick called "howard johnson roof" FD LOL!) on an analog ADI...was just, tough to get used to. I'm going back up in the 732 sim this Sunday in ATL  Love , I'm sure there'll be a few cobwebs to dust off. Thought I'd learn something more about FD's before I go..

I've seen pics of AA 756's...they have single cue, it just looks weird on an EADI...guess it's the software package. Which a/c's can you select either on? (would be pretty cool!)

DeltaGuy  Smokin cool

Topic: RE: Flight Director Preference: Needles Or Inverted V?
Username: Jetguy
Posted 2004-03-10 19:07:22 and read 5275 times.

I guess that I'm going to be the one with the differing preference. Personally I prefer the ^ bar presentation, but that's purely because it's the one I'm most familiar with. I did fly a Citation Bravo, a couple of weeks ago, that had a selectable presentation (either ^ or +). I played around with the cross pointers a little bit, but not enough to gain a comfort level with them.

Jetguy

Topic: RE: Flight Director Preference: Needles Or Inverted V?
Username: B747Skipper
Posted 2004-03-10 19:38:37 and read 5272 times.

With PanAm, we had the Sperry double cue systems... Then I flew other airplanes with Collins single cue... Right here, my airline has single cue Collins, was probably the preference of the director of operations or chief pilot at the time the airplanes were ordered...
xxx
On the line, as a result, I have a Collins (often, I place my F/D switch off), but I have to admit that when on a long sector and I am tired, flying "formation" with the "V bars" is easier. But if I am tired, I am no longer the type of pilot to impress how sharp I can fly an approach to minimums, I merely select the autopilots for a coupled approach...
xxx
I have noticed that with the Collins "V bars", I constantly cross check with the raw data display (RH side of ADI) to get a "trend" of the glide slope, before my eyes can see a correction command from the V bars. Same thing, I use the "runway" (bottom of ADI) since it is so accurate for localizer tracking.
xxx
My only happiness is that in all the simulators we use for training, they all have Sperry dual cue displays, so for the training and check rides, we have the most accurate displays. Lucky.
xxx
This is not an Airbus vs. Boeing or Bendix vs. Collins issue... it is just an opinion.
Whatever makes your flying easier... I now log a lot of autopilot time...
xxx
Happy contrails  Smile
(s) Skipper

Topic: RE: Flight Director Preference: Needles Or Inverted V?
Username: Fly727
Posted 2004-03-10 20:45:32 and read 5254 times.

Since it is the only one I've flown so far, I'll say that my choice is the "inverted V". The needles (dual cue) looks nice and seems to make our life easier though.

RM  Smile

Topic: RE: Flight Director Preference: Needles Or Inverted V?
Username: Klaus
Posted 2004-03-10 22:15:40 and read 5246 times.

Layman question after not finding anything useful on the Net:
Which information is displayed and how? A pointer to an explanation would be fine with me.

Is it deviation from selected glide path and heading?

I´m not flying, just curious.  Wink/being sarcastic

Topic: RE: Flight Director Preference: Needles Or Inverted V?
Username: FDXmech
Posted 2004-03-11 08:23:28 and read 5199 times.

>>>Is it deviation from selected glide path and heading?<<<

The flight director gives the pilot a graphic representation of the flight path (both vertical and lateral) he should be flying or that the autopilot should be following.

Perhaps a crude analogy would be lines on a highway. This gives the driver a graphic reference of where he should be in relation to the width of the road and gives visual clues to curves on the roadway that must be followed.

Topic: RE: Flight Director Preference: Needles Or Inverted V?
Username: FDXmech
Posted 2004-03-11 09:27:25 and read 5190 times.

Here's a good example of the flight director in straight and level flight.
The flight director consists of the two light green bars forming a cross (+) overlaying the airplane symbol on the Primary Flight Display (PFD). The vertical bar is the roll bar . The horizontal bar is the pitch bar. Notice how the bars are centered on the airplane symbol and not the horizon.
The bar(s) will displace left/right or up/down giving the pilot a visual cue to follow the desired vertical and lateral track. And also allowing the pilot watch the performance of the autopilot.


View Large View Medium
Click here for bigger photo!

Photo © Florian Sindermann



Here's an example (a little fuzzy) of the airplane making a right turn. But look at how the flight director bars are centered on the airplane symbol. The airplane is right where it should be at this point in time. Look at the Nav Display (ND) and compare manuever being performed with the desired flight path coming out of this holding pattern. Interesting


View Large View Medium
Click here for bigger photo!

Photo © Ivan Rodriguez - IBERIAN SPOTTERS


Topic: RE: Flight Director Preference: Needles Or Inverted V?
Username: B747Skipper
Posted 2004-03-11 09:41:25 and read 5187 times.

Dear Klaus -
xxx
I do not know your knowledge of aircraft flight instruments.
Let me try to explain in very simple terms...
In the middle of flight instruments, we have an "artificial horizon"
Oftentimes the top of display is blue (the sky), bottom is grey (earth).
A line separates the two (the "horizon")...
In the middle, there is a symbol representing the aircraft (the wings).
If the plane goes up, it is climbing, or turns (banks)...
xxx
In the "single cue" display, the "v bars" indicate which way to go...
Up, down, bank left, bank right.
All you have to do, is to match your airplane symbol into the "v bars"...
xxx
In the "double cue" display, the vertical bar gives a command left or right.
If the vertical bar goes to the left, bank the plane symbol to the left.
If you satisfy the command, the vertical line will go to center.
Same for the horizontal bar, bar goes down, put the airplane symbol down.
If the command is stisfied, the horizontal bar goes to the center.
xxx
Commands "satisfied" is the airplane symbol matching the V bars.
I sometimes say "fly formation in or with the V bars...
Or the needles in the center (for double cue displays)...
Perfect cross is in the center.
This display is used to fly i.e. an ILS approach.
Guidance for the localizer and the glide path.
xxx
I did not know how to explain to you, Klaus... hope this helps...  Big grin
Happy contrails -
(s) Skipper

Topic: RE: Flight Director Preference: Needles Or Inverted V?
Username: Ba299
Posted 2004-03-11 11:50:54 and read 5176 times.

My vote go to + dual cue FD. I never flown an aircraft with single cue so I can't tall you how it's fly with single cue.

Topic: FDXmech, B747Skipper
Username: Klaus
Posted 2004-03-11 15:02:43 and read 5169 times.

Thank you for your explanations.
I think I´ve got some understanding of the more important instruments, but this part was still missing.
Apparently I had guessed correctly, just couldn´t find a confirmation on the Net, especially none with pictures.

Thanks again!  Big thumbs up

Topic: RE: Flight Director Preference: Needles Or Inverted V?
Username: JBirdAV8r
Posted 2004-03-11 16:27:23 and read 5140 times.

For me, I've grown accustomed to dual cue, just easier to work with I think.

Oh, really...must be all that hard IFR time you spend in 20-year-old Cessna 172's, you think?  Yeah sure

Topic: RE: Flight Director Preference: Needles Or Inverted V?
Username: DeltaGuy
Posted 2004-03-11 16:45:23 and read 5131 times.

Oh, really...must be all that hard IFR time you spend in 20-year-old Cessna 172's, you think?

Thanks for the smartass reply...it was more like sim time in the MD-88. I'm not here to compare medals, alls I want to know is tech stuff. So leave it at that.


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