Thanks for the good explaination
But it´s not good being too fast in that 737 as long as the speed brake lever control behaviour is not patched. It is always funny to spend at least five minutes clicking a thousand times on that speedbrake lever because it cannot be grabbed and moved with the mouse.
By the way… some people say the Boeing 737 speedbrakes are not very good and efficient, it is even said that the speedbrakes are just some soft back-massage
Why is that? On the A320 the speedbrakes barely come out even when fully released.
And some aircraft have speedbrakes that look like the size of my palm (like for example the Mooney M20) so the Boeing speedbrakes look very efficient.
Last night I was flying RJAA (Narita) to RJOO (Osaka) and as I always try to copy real world flights I was watching flightradar24 and witnessed two 738’s (first JAL and second ANA) approaching the same STAR to RJOO 32L descending below 10,000 ft. I noticed that the gap between them was closing because the ANA was clearly faster than 250 kts. It ended JAL vacating the runway and ANA on a really short final. They were taxiing to gates together. Phew. So much for the 250/10,000 speed limit
The A320 will only give you 50% of the speed brake regardless of lever position in flight, you can fully pull back the lever but the computers will limit the movement to 50%. The A321 and I beleive the A319 do not do this. That may explain why it seems less.
If you look on the 737 there is a mark on the speed brake called Flight Detent which I beleive is the max position you can pull the speed brakes too I am not sure if this hard limited by the plane or just something the pilots must be cautious of, maybe @FormerSnail5736 could explain this or chime in on it. I can imagine there needing to be some limit on it as too much air disruption can’t be a good thing? I also think wing area plays a part in the efficiency and shape of the of the speed brakes, if you look at the Avro vulcan its speed brakes look very similar to the mooney’s but seem to do the job, so I am guessing shape and design play a huge role in it too.
Time stamped video of the Avro Vulcan speed brakes:
Yeah I’ve heard that too. But they work just fine. It’s a passenger airplane, not an f15.
Of course, like in most airplanes, at slow speeds they’re not effective but if you’re descending at 300kts they are really effective and will give you +4500fpm descents easily.
Question about trimming. You dont really see the exact trimmed value is that correct? For example when you need 4.82 you just can roughly guess where that value is on the trimm wheel?
Hi,
I’m in my first few flights with the 738. Having troubles really understand how the FMC and LNAV works. Issue here: after having set the fltplan, I can’t set LNAV (got it work in a previous flight). It is telling : not on intercept heading. I saw you should be within 3 nm of the magenta line before the next WP. Still not working.
Any ideas ? Thanks!
Yeah. It is the first WP of the route. I understand that it is still the one that is active (in magenta color). Two hours later on the flight and still not able to put it on LNAV… Any way to put it the next WP as active?
The waypoint in the top right if the display is a long way away. It’s hard to tell looking at your flightplan as it’s not screengrabbed on page1, and you are extremely zoomed in at 5 mile range.
You can usually activate a waypoint by selecting the one you want (button next to it to copy it and button next to 1st point in the FMS to paste it over the current target waypoint. I think occasionally you have to hit ‘Activate’ if it appears at the foot of the FMS or hit ‘EXE’ if the EXE switch gets lit.
I’d also step through your flightplan in PLN mode to check that it’s all as expected and that it all joins together with no discontinuities.
I’ve seen this message when your current heading is not taking you towards the flightplan - I think also if it is crossing the flightplan at an angle of more than 90 degrees from where you want to go (so kind of crossing the flightplan in the wrong direction). If this happens, LNAV won’t engage. To fix it you need to turn so you’re flying towards the flightplan and will intercept it in roughly the right direction. Then LNAV can be engaged and it will fly you to join up with the flightplan.
Not sure if that’s what’s going on here, but you could try it?
Is there ever any situation where speed brakes are used on the approach. Today I was landing RNAV 11 at LEXJ, after vectoring to the FAF alt 1400 I think, I could not get the speed under control for a while the wind was bouncing me every which way.
It was close but I got down Vref +8 I would say and a little bounce, I wondered after would the speed brakes of helped, but as you said above they work better at higher speeds.
Just wondering is using the speed brakes on approach a thing or a no no.
Is there anyway to resize the pop out instruments (like old FSX window sizing_), e.g. PFD and ND for the PMDG, they are massive and resizing manually is a pain every time…Ive tried the popout manger and its got more bugs than bugs bunny!!
Yes of course. Like I said above, the 737 is a slippery airplane (like most nowadays). Speedbrakes on the first parts of the approach are common especially when there’s tailwind. The recommendation is to never use speedbrakes with F15 or more. F10+speebrake is common. Make sure to stow the speedbrakes before you go GearDown+F15 (which in my case happens at 4nm in VMC and 5nm in IMC).
Having said that, VREF+8 is more than ok. At the landing gate, as long as you’re between VREF and VREF+15, you can consider to the approach to be stabilized in terms of speed (provided you meet the rest of the stabilized approach criteria).
