Ok, I think my confusion is the hud. The dashed line in the hud goes away, but the director bars in the PFD are there. Don't even have to load vnav, toga makes the bars appear, and vnav automatically comes on at 1000 feet.

 

I'll probably just get off using the hud on takeoffs.

All great advice and I'll read the posts a few times to digest it all. I made the flight tonight(well currently enroute to Detroit). I loaded the vnav at the runway and it armed. As I'm rolling though in toga, the vnav disengaged and would not re engage. After takeoff, just kept wings level and trimmed to a consistent climb.. engaged at, then vnav and hdg... Pulled flaps up crossing speed bugs. All was just fine.

 

I am wondering though, why is vnav disengaging? I'd like to try a manual flight out but would,like to have those director bars to help with the vertical.

By director bar I mean the dashed line on the hud

 

My SOP, which I think is consistent with airlines, is to have the Autothrottle switch in the ON position before takeoff. Engage the flight director switch, then the A/T switch, then VNAV and LNAV all on the ground. VNAV goes off when you engage TOGA but you get the flight director as it's armed. Same with LNAV (or HDG SEL if you need that). When you get above 400 AGL you can engage CMD A or CMD B and those modes will become active. 

 

Ok, I think my confusion is the hud. The dashed line in the hud goes away, but the director bars in the PFD are there. Don't even have to load vnav, toga makes the bars appear, and vnav automatically comes on at 1000 feet.

 

I'll probably just get off using the hud on takeoffs.

 

I don't think anyone uses the HUD for take-off, though I'm sure you can. You might be interested in FCOM 2 section 4.20.14 which describes the EFIS/FMA readouts for using the Flight Director and Autopilot during takeoff. The various lines and dashes on the HUD are meant for approaches mostly. Section 10.10.14 describes what said various lines mean on the attitude indicator.

 

Which dashed lines are you referring to? There are lines that indicate the pitch limit (two horizontal bars with "flags" that jut out) and there's the Flight Director "+" which can sometimes be more like a V or an arrow. On the HUD, this is represented as two circles, one large and one small. You are going where the large one is pointed, and you should be going where the small one is. When you center the two, you are going the right way. I believe this is call a "flight path vector." There is a button next to the MINS knob labeled "FPV" which will active one on the Primary Flight Display.

 

Regardless, I think your main focus should be on trimming to relieve back pressure on the controls. You can hop into a 172 or other GA aircraft to see more clearly how trim affects flying.

 

Matt Kramer

Edited August 5, 20169 yr by pilot3033

 

 

Which dashed lines are you referring to?

 

I've been messing around with flaps 25 takeoffs at SNA and did one with the HUD down to try and see what you saw. Perhaps the dashed line you're referring to on the HUD is the same pitch limit line I described. On the HUD, it appears as a dashed line that runs horizontal across the entire display. Remember, on the HUD you're nose is represented by a -v- symbol, and the pitch degrees flow quite rapidly during rotation, especially if you're uncoordinated. 

 

Matt Kramer

 

 

I am wondering though, why is vnav disengaging?

 

VNAV is disengaging? Curious...  :wink:

(You may find it helpful to run Tutorial #1 again to see if you pick up on more of the minutia now that you have experience with the plane and aren't drinking from a fire hose as you were when first beginning.)

 

As mentioned, this is appropriate/correct, and this is where the obligatory mention of the FMA comes in. The MCP is nice and has cool buttons and lights, but in the end, there's only one thing that really matters: the FMA. Had you'd checked that, you would've seen TO/GA annunciated where VNAV PTH/SPD would otherwise be (with the white 'VNAV' below it to indicate armed). As such, the light goes out until the conditions are met (mainly, until above 400' where VNAV will take over, and therefore indicate active on both the FMA and MCP).

 

 

 

I'd like to try a manual flight out but would,like to have those director bars to help with the vertical.
By director bar I mean the dashed line on the hud

 

The dashed line on the HUD? That's the pitch limit bar. Definitely don't go chasing that...

 

The Flight Director on the HUD is the circle. Put the "winged" circle around the circle.

The dashed line on the HUD? That's the pitch limit bar.

 

OK, I had to go back to the HUD Pilot Guide - in that guide that dashed line is called the TO/GA Pitch Target Line. No idea where I came up with that as the flight director and probably caused alot of my issues. 

 

 

I don't think anyone uses the HUD for take-off, though I'm sure you can

 

Yeah, I'm going to stop using it on takeoffs. Works great on landings though, just for the aircraft reference symbol and the speed tape error. So very helpful. The 3 degree line also getting that right on the touchdown zone works well. I cannot use the flight path symbol and guidance cue technique, I tried it once and it was just a mess. 

 

 

 

I think your main focus should be on trimming to relieve back pressure on the controls.

 

I've found I need to be less active with the trim, I laid off it last night and found that the trim setting in the preflight did what its supposed to do and its pretty solid during the initial climb. 

 

 

OK, I had to go back to the HUD Pilot Guide - in that guide that dashed line is called the TO/GA Pitch Target Line. No idea where I came up with that as the flight director and probably caused alot of my issues. 

 

Could be, yeah. And sorry for mis-speaking earlier. The pilot guide obviously uses the proper term. The term I used was misleading. Either way, it's definitely not the director.

 

 

 

Yeah, I'm going to stop using it on takeoffs. Works great on landings though, just for the aircraft reference symbol and the speed tape error. So very helpful. The 3 degree line also getting that right on the touchdown zone works well. I cannot use the flight path symbol and guidance cue technique, I tried it once and it was just a mess. 

 

Why stop using it on takeoff? Just because some operators don't doesn't mean that they can't, or that you shouldn't.

 

 

Why stop using it on takeoff?

It wasn't an issue until I started using it for the guidance cue... 

95% of the other takeoffs were standard flaps 1 takeoffs - like the tutorials. So after the roll and climb, it was very quickly engaging all the automation. Pretty much immediately after the Pitch Target line disappeared, it was pan over and turn on the automation.

Well, with a flaps 15 (honestly looking back I don't know why it was so much different or why I had so many problems) it accelerated alot slower, so forcing the wheel to follow that pitch target line stopped acceleration at just above V2... and then when the pitch line disappeared after the initial climb (like it's supposed to) I must have been pitching too high and I would actually start to lose speed. So the plane would get out of trim, and heres me trying to engage the AP... but it wouldn't engage because I had pressure on the stick (pushing down to pick up that speed) - and I guess it just snowballed and I was constantly behind the plane trying to catch it up.

So if its pitch guidance I want, I should be looking at the PFD, cause that info just isn't in the HUD. Simon K had alot of things to consider, scanning the instruments and such to gain situational awareness... whats going on with the plane. 

So easy to get into a pattern of how to do things without really understanding whats going on. This is my problem, and likely a huge problem with simmers - in this case doing the tutorial and flying it 95% of the time, that one tweak of going from flaps 1 takeoff to flaps 15 threw me for a loop. Something simple turned complex because it was just out of the norm.
 

I've told people yeah I can fly a real 737... if everything goes perfect and ideal... if anything goes wrong or different, that plane might be going down. Thats why we pay professional pilots..to be there when things don't go as planned. 

Ever since i started flying pitch / power combinations (specially on manual landing) the whole ride became much smoother.

 

(For the 733 mind! But differs not much) takeoff with v2 in mcp set. Vr lift to 15 then on to ca.18 degs nose up. With toga speeds stays around v2 that way. 400ft agl lnav or other roll mode. At accel height dial up 220 ias in mcp or other >flap up spd. Pitch down to 10deg and check mcp speed mode / vnav active. Raise flaps per schedule.

 

I use 3000ft as accel alti so can do my contacting atc in the bit where i only have to focus on pitch.

 

Only after reaching the mcp speed at 10deg pitch i start to follow the vnav part of the fd, as smoothly as possible. (Irl large pitch movements tend to increase vomit tendencies )

 

Hth

 

 

So if its pitch guidance I want, I should be looking at the PFD, cause that info just isn't in the HUD.

 

It is. I already mentioned this earlier, actually. It just doesn't look the same as on the PFD.

 

On the HUD, you will have your velocity vector, which looks like a winged circle: _/O\_

There will also be a plain old circle that will wander around: O

 

That plain old wandering circle is the path that you have to capture with your winged circle, thusly (sorry for the poor qual - it's a screengrab from the aforementioned tutorial):

 

[Click Here - until I can figure out how the Goggle managed to screw up image embedding...]

 

 

 

So easy to get into a pattern of how to do things without really understanding whats going on. This is my problem, and likely a huge problem with simmers - in this case doing the tutorial and flying it 95% of the time, that one tweak of going from flaps 1 takeoff to flaps 15 threw me for a loop. Something simple turned complex because it was just out of the norm.

 

I'd argue that this is due to making quick assumptions and judgments without fully recognizing what goes into it, usually due to limiting inputs to only a handful of sources. I'm glad that you come to the forum to get questions answered, but remember to slow down sometimes and let the dust of the new knowledge settle.

 

 

On the HUD, you will have your velocity vector, which looks like a winged circle: _/O\_
There will also be a plain old circle that will wander around: O

The velocity vector is called the flight path symbol in the manual. It's where the plane is actually going.  Circle is called guidance cue. You're right, you're supposed to capture the circle with the bigger circle. I tried this once, it didn't go very well. 

At this time I don't do well with the HUD guidance, but do well with bars in the PFD. 

 

 

 

quick assumptions and judgments

Yeah you nailed it.

dust of the new knowledge settle.

Yes, again lots of info in this thread, lots of suggestions, lots of POV, lots of things to consider. Great resource here.

 

 

The velocity vector is called the flight path symbol in the manual. It's where the plane is actually going.  Circle is called guidance cue. You're right, you're supposed to capture the circle with the bigger circle. I tried this once, it didn't go very well. 

 

I'm pretty sure I ended up calling it the flight path vector in the tutorial. I guess my mind just jammed the two terms together.

 

It takes a little practice to finesse it.

 

 

 

At this time I don't do well with the HUD guidance, but do well with bars in the PFD. 

 

Whatever is easiest.

 

 

 

Yeah you nailed it.

 

Pretty common. I know I definitely fall into this category from time to time, and especially when I first started flying.

 

 

 

Yes, again lots of info in this thread, lots of suggestions, lots of POV, lots of things to consider. Great resource here.

 

Yeah, there's a ton of stuff that will need to settle in before it all comes together.

 

 

The velocity vector is called the flight path symbol in the manual. It's where the plane is actually going.  Circle is called guidance cue. You're right, you're supposed to capture the circle with the bigger circle. I tried this once, it didn't go very well. 

 

Yeah. I've not flown an HUD before but I can imagine why that might not work too well in a takeoff.

 

The FPV (flight path symbol, etc) is great at times when you are flying a defined 3D path in space (like on approach, where you are flying tightly defined lateral and vertical paths). But in the initial climb, you're not targeting a well-defined vertical path -- you're flying pitch and power and accepting the vertical path that you get as a result. I can see how chasing a flight path guidance symbol in that situation could get you in to all sorts of trouble.

 

The Airbus automatically dumps the bird (FPV) and gives you standard dual-cue FD bars in a go around for precisely this reason.

 

 

I don't think anyone uses the HUD for take-off, though I'm sure you can.

 

Wrong. The first HUD for the 737 was for Alaska Airlines ASA specifically for departures out of Sea-Tac. Departures were being delayed more often than arrivals so the HUD was introduced.

 

I've not flown an HUD before but I can imagine why that might not work too well in a takeoff.

 

I don't know why not. Just dial in the appropriate ILS to provide center line guidance and it makes virtually zero-zero takeoff possible. I usually use the HUD for departures as well as arrivals, just a matter of experience I think.

Hi Dan,

 

 

 

I don't know why not. Just dial in the appropriate ILS to provide center line guidance and it makes virtually zero-zero takeoff possible. I usually use the HUD for departures as well as arrivals, just a matter of experience I think.

 

I'm sure it's possible and perhaps there are some benefits -- it's not the HUD itself that's the problem -- it's the flight path target which personally I don't think is optimal for takeoff/climb where you're not really pitching for flightpath, you're pitching for speed. I can envisage why it would be easy to end up chasing a flight path target around the sky compared to just flying a pitch and fixed thrust setting with (or without) the aid of conventional FD bars.

As Dan mentioned, my operator started using the HUD for low-vis takeoffs years ago. Dial in the ILS, line up on the runway, and just adjust your course on the MCP until the centerline guidance overlays the real centerline (it won't always exactly be the published ILS course.) You've then got centerline tracking, and in the real plane you've got runway distance remaining. Even on clear days, our captains are mandated to use the HUD on all takeoffs in 800s and 900s, for tailstrike awareness (the 400 and 700 are short enough that it's not as much of a concern).

 

I've always heard that the flight guidance in the real HUD is much more sensitive than the flight director on the PFD. I don't have enough experience with the real thing to say one way or the other, but it seems in the ngx that the HUD flight guidance lags the PFD flight guidance a bit, which leads to less precise control. This could just be on my computer though; it's definitely not a gaming rig and the ngx (with orbx etc) pushes its limits.