Flight Director 'No Mode'

[Capt Pit Bull]

A quick question regarding flight directors. All my commercial types (as configured where I've worked) have used cross bar flight directors.

In such, when an axis has no mode (or is in 'basic mode' or whatever the manufacturer calls it) the bar in question can be removed from the graphics (or biased out of view for clockwork panels).

What happens on V bar presentations? Is there an off flag or something?

CPB

[411A]

Can't comment about many other types, but the TriStar with the (Collins) 'V' bar presentation can do either...

Bias out of view, or sync to the present aircraft attitude (with no steering info available, only vertical).

Both pilot selectable.

Quite frankly, I've always preferred the 'Sperry' cross-pointer presentation, as I started on the Zero Reader, a very long time ago.

[777300ER]

Although there may be exceptions, one of the greatest advantages to the dual-cue (crosshairs) flight director is the fact that you can still utilize one channel of the system in the way you described. Most single cue (V bar) flight directors are all or nothing in this regard.

[wondering]

From my observation the 'lateral' portion of the FD will revert to ROLL mode and the 'vertical' portion to PITCH mode. When selecting the FD on w/o any lateral/vertical mode it will show ROLL and PITCH mode as well. I reckon those are the 'default' modes.

[ICT_SLB]

Wondering is correct, on the majority of Autopilots Roll & Pitch are the default modes (and not annunciated on Rockwell-Collins APs). On a typical mode without a equivalent alternate axis - Back Course, for example, where there is no Glideslope vertical guidance, most pilots I've flown with will select another source such as Vertical Speed (VS) otherwise the default will be Pitch using the value at selection - effectively giving you Pitch Hold. In either case, the V-bar will still be displayed and give you Roll steering about whatever Pitch value/source you select.

[despegue]

Well, most of my fellow countrymen at my current airline don't use the F/D at all. Whenever possible, we fly our departures completely raw data up to cruising level, whereafter we will put the F/S's on, followed by the A/P. The same goes for our Approaches. F/D off on TOD. Obviously only when weather conditions allow.
The F/D is actually quite a useless thingie!:cool:

And yes, I'm Belgian...

[Blacksheep]

Dpending on the manufacturer and the airline's choice of pin selectable options, the usual default is attitude - other steering signals are mixed with attitude anyway. So for example, with no glideslope steering - the V bars give you the pitch attitude hold that the glideslope signal would have been mixed with anyway, while giving roll steering to follow the localiser.

Don't bother with the F/D despegue? On complex aircraft, with auto-land capability the Captain and F/O's Flight Directors should be used for monitoring the signal activity of the 2nd & 3rd channels. Its a majority voting system, you see. Best to know what all three of the channels are up to...

[411A]

\\\On complex aircraft, with auto-land capability the Captain and F/O's Flight Directors should be used for monitoring the signal activity of the 2nd & 3rd channels. Its a majority voting system, you see. Best to know what all three of the channels are up to...\\\

Or, as on just slightly more advanced types (Lockheed TriStar) there are four...:ooh:

Those F/D's are certainly required, by certification, for LVP.
Best to make sure they work as advertised.:}

[despegue]

Blacksheep,

We must never forget that we are pilots, and NOT slaves of the autopilot and F/D.
The Flash Air crash last year is the perfect example of loss of situational awareness, blind trust in automatics and a general situation of being out of contact with the aircraft.
We are pilots and should be able to fly our aircraft smoothly and accurately. I come from an airline ( a Eastern European LCC) where A/P was mostly used as soon as possible and where raw-data was unheard of. Now, I fly with ex-Sabena and Sobelair collegues and I've only now started to learn to FLY the aircraft, not only manage it. Before, I followed a cross, actually moving the controls on the B737. Now, I learned to work with pressure. Smoothli give pressure on the controls to manipulate, that is all. FEEL what the aircraft is telling you, you won't be able to do this when following magenta crosses or V-bars. And if someone doubts about the sanity of the Belgians, you all now pretty well that SN and SLR had the reputation to be one of the safest around, and their crews among the most competent and best trained. I used to be afraid of raw-data and that is ALWAYS a bad sign.
Obviously, we DO use A/P and all the management systems whenever this will actually enhance safety. That is pure airmanship. IMC conditions will be flown in F/D or A/P mode, the same goes for extremely busy environments.

[White Knight]

Despegue, whilst practicing raw data is admirable, and helpful to maintaining skill - doing it during flying a SID out of major european airports is NOT admirable, nor during the approach phase!! Too easy to bust heading, altitude, speed etc!!

411a - guess the 1011 needed 4 autopilots as they're all a bit old hat:{

[wondering]

I thought, I gave a reasonable answer. To be more specific, I was talking about the Collins Pro Line 4. In real life, I have seen the mode annunciator changing in cruise for no apparent reason fom NAV mode to ROLL mode and the V bar was just going along with it. Of course, other V bars and avionic systems may behave differently.

[despegue]

on the B737, lose either lateral or vertical mode, and the V-bar will dissapear.

With the cross-bar, only the affected bar will vanish.

[Ignition Override]

Not long ago at a major US airport, the ILS glideslope appeared on the ADI-several MILES early, and was stuck in the center position, indicating on glideslope! There was certainly no computer or other such flag on the ADI. But it never appeared on the HSI glideslope repeater. I hope that Maint. was able to repair it. We rarley keep the same plane in a hub (further delaying the next flight as we preflight the next plane, already delayed inbound due to weather etc).