When is the exact moment you are supposed to disconnect the A/T

[JoeDiamond 67]

Wow. Your procedure completely contradicts the recommendation Boeing has stated in our manuals. Live and learn :unsure:

 

I asked that same question when I was getting the type rating and was told the procedure was recommended by Boeing, go figure.

 

In any case it works well.  For a flap 30 landing the A/T rate of retard is just about perfect.  When landing flaps 40 I usually resist the throttle retard a bit.  For 15 you need to retard them fully before the A/T does.

 

We are not prohibited from disengaging the A/T for landing but if we do and the FO is flying then you have to add a wind correction to the approach speed.  If the A/T is left engaged until touchdown or the captain is flying the approach with the HUD then you are good with just Vref+5.  I'd say 99% of the guys I have flown with leave them on, myself included.  Also, by leaving them engaged you can TOGA at any time and the power will come up automatically.

[Spin737 102]

 

 

We are not prohibited from disengaging the A/T for landing but if we do and the FO is flying then you have to add a wind correction to the approach speed. If the A/T is left engaged until touchdown or the captain is flying the approach with the HUD then you are good with just Vref+5. I'd say 99% of the guys I have flown with leave them on, myself included. Also, by leaving them engaged you can TOGA at any time and the power will come up automatically.

That's starting to get too complicated for my little head. I JS on AA weekly. I'm going to have to pay more attention on landing next time.

 

I've done some left seat HUD stuff, but only as a sim partner. So the HUD allows you to remove the additive, huh? Is the energy-dealy thing on the wing? (I'd look up the term, but "energy-dealy" sounds good.) Is that anywhere in the Boeing books or is that in-house only?

[smilingjoe 0]

From what I understand (off the internet of course, so who knows how valid it is), but originally the Boeing procedures were to turn off the auto-throttle, but recently they made a software logic update to the 737 to allow the throttle to be used past touchdown, in order for the main procedures to more closely follow to big boeings procedures (such as the 777) to make it easier to transition from one aircraft to another

[FL630 3]

Whilst it's not a Boeing related answer, have you ever noticed on an Airbus the countdown will be 100, 50, 40, 30, 20, retard retard, 10.....?

 

Retard is to retard the throttle (not the aircraft being nasty about your flying skills   ) and it arrives somewhere between the 20-10ft mark. So keep the AT on all the way to the point it then tells you to cut the power. So if you wish to cut the power, it's at this sort of height you'd do it. Obviously windy or gusty conditions may change this, but in calm or "normal" conditions I see no reason why you'd want to disengage the AT's, it's just more workload at the time in the flight where you least want it. Added to that in the sim-world, you're flying single pilot, you've not got somebody else to take half the workload.

 

It makes sense to me to have the power idled when you touch down for obvious reasons. I wont argue a real airlines SOP's, but I assume you keep it on as a way to increase the safety factor in the event of a go-around with the trade off of a longer LDR? The majority of 737's I see land tend to idle before they touch down, of course though this may be a SOP of RYR.

 

As a query to JoeDiamond, if you're flying either heavy, hot, high, humid or off contaminated runways, do you keep AT engaged?

[JoeDiamond 67]

That's starting to get too complicated for my little head. I JS on AA weekly. I'm going to have to pay more attention on landing next time.

 

I've done some left seat HUD stuff, but only as a sim partner. So the HUD allows you to remove the additive, huh? Is the energy-dealy thing on the wing? (I'd look up the term, but "energy-dealy" sounds good.) Is that anywhere in the Boeing books or is that in-house only?

 

It's in our AOM.  The only original Boeing book we have is the Volume 2, so I couldn't tell you if it's in the current Boeing FCTM or not.  I remember the instructor saying something about Boeing having changed the recommended procedure at one time so it's possible they have changed it there as well.

 

Since the captain has the flight path acceleration caret and the speed error tape on the HUD they let him get away with ref+5 for all approaches, A/T or not.  Like you I have only done enough left seat stuff to get the type rating and they don't give me one of those fancy HUD things on my side of the airplane so I just leave the A/T on to keep the math simple.  I did go to public school after all   I'm told our 787's will have a HUD on both sides.

 

 

It makes sense to me to have the power idled when you touch down for obvious reasons. I wont argue a real airlines SOP's, but I assume you keep it on as a way to increase the safety factor in the event of a go-around with the trade off of a longer LDR? The majority of 737's I see land tend to idle before they touch down, of course though this may be a SOP of RY

 

You can still move the levers with the A/T engaged so if they aren't coming back at the rate you like you can simply pull them back, or hold them up if they retard before you want them to.  If you let them go they will attempt to go back where the A/T wants them so you just hold them until the A/T disengages after touchdown.

[FL630 3]

You can still move the levers with the A/T engaged so if they aren't coming back at the rate you like you can simply pull them back, or hold them up if they retard before you want them to.  If you let them go they will attempt to go back where the A/T wants them so you just hold them until the A/T disengages after touchdown.

 

So the Boeing A/T retards automatically when you get to the right height? Do they retard fully before touchdown or do they hold the selected airspeed until touchdown then retard? Surely if it's the latter you're have a huge adverse effect on LDA?

 

I've edited my above post, the question regarding the hot/high was to you, I just got confused by user names.

[JoeDiamond 67]

At approximately 27' RA the retard mode engages and they will retard fully, reaching idle right about the time you touch down. The selected airspeed is ignored. If you are landing with flaps 30 the timing is just about perfect. If landing with flaps 40 you need to resist the A/T a little bit so the levers come back slower. On a flaps 15 landing you need to start reducing thrust before the A/T does or you will float.

 

 

Sent from my iPad using Tapatalk

[g_precentralis 191]

 

 

I see no reason why you'd want to disengage the AT's, it's just more workload at the time in the flight where you least want it. Added to that in the sim-world, you're flying single pilot, you've not got somebody else to take half the workload.

Tell that to Turkish 1951 crew crashed at Amsterdam.

[JoeDiamond 67]

As a query to JoeDiamond, if you're flying either heavy, hot, high, humid or off contaminated runways, do you keep AT engaged?

They are always on. The only time I disengage them is if an abnormal procedure calls for it. On a normal flight I never have to touch the A/T disconnect buttons. Some guys disengage them for landing as their personal preference, but not many. It's allowed but from the right seat you need to start adjusting the approach speed for wind. It's simpler just to leave them on and use vref+5.

 

Anytime the A/T is engaged you can still move the thrust levers to override it. Unless the A/T is in the ARM mode the levers will return to wherever the A/T wants them when you let go. If for example you get a momentary speed decrease during cruise and the A/T isn't correcting as quickly as you like you can add a bit of thrust manually and then let go.

 

In the NGX the retard mode only seems to engage if the approach mode is active. The real airplane isn't like that. You can hand fly a visual approach with MCP SPD engaged and they will retard. The only time they won't is on a non-precision approach using VNAV when the missed approach point is prior to the runway threshold. In that situation the will go into ARM when you pass the missed approach point and you will need to retard them manually. To get around that you can select V/S once you have the runway in sight. That puts the A/T into MCP SPD and the retard mode will engage normally.

 

 

Sent from my iPad using Tapatalk

[FL630 3]

Tell that to Turkish 1951 crew crashed at Amsterdam.

 

Agreed, whilst the A/T physically caused the crash but cutting the power, the lack of instrument scan to pick up the faulty rad alt might have been the more major issue 

They are always on. The only time I disengage them is if an abnormal procedure calls for it. On a normal flight I never have to touch the A/T disconnect buttons. Some guys disengage them for landing as their personal preference, but not many. It's allowed but from the right seat you need to start adjusting the approach speed for wind. It's simpler just to leave them on and use vref+5.

 

Anytime the A/T is engaged you can still move the thrust levers to override it. Unless the A/T is in the ARM mode the levers will return to wherever the A/T wants them when you let go. If for example you get a momentary speed decrease during cruise and the A/T isn't correcting as quickly as you like you can add a bit of thrust manually and then let go.

 

In the NGX the retard mode only seems to engage if the approach mode is active. The real airplane isn't like that. You can hand fly a visual approach with MCP SPD engaged and they will retard. The only time they won't is on a non-precision approach using VNAV when the missed approach point is prior to the runway threshold. In that situation the will go into ARM when you pass the missed approach point and you will need to retard them manually. To get around that you can select V/S once you have the runway in sight. That puts the A/T into MCP SPD and the retard mode will engage normally.

 

 

Sent from my iPad using Tapatalk

 

Interesting, thanks for the detailed response! Hopefully I'll be doing my type rating on the 738 this year, so it's great to hear how these things work from people who use them daily.

[g_precentralis 191]

Agreed, whilst the A/T physically caused the crash but cutting the power, the lack of instrument scan to pick up the faulty rad alt might have been the more major issue 

 

Agree, many factors contributed, even improper ATC procedures, but my argument is A/T do not decreases workload in every situation, it just disconnect pilot from aircraft during critical phase of flight, so IMO it even increases workload.

[FL630 3]

Agree, many factors contributed, even improper ATC procedures, but my argument is A/T do not decreases workload in every situation, it just disconnect pilot from aircraft during critical phase of flight, so IMO it even increases workload.

 

I'm not sure I agree with that, surely when you're concentrating on the landing it's far easier to monitor the speed rather than control it on top of all the other things you're looking at/busy doing. If you extend this logic, why not fly the approach completely manually?

[g_precentralis 191]

I'm not sure I agree with that, surely when you're concentrating on the landing it's far easier to monitor the speed rather than control it on top of all the other things you're looking at/busy doing. If you extend this logic, why not fly the approach completely manually?

 

Look at that crash with jammed throttle leaver during take off. Pilot could prevent it if he monitored performance of AT, but he fell into false sense of security thinking that AT is decreasing his workload. In fact there were one more thing to monitor than with manual take off.

 

IMO, it's completely fine to fly an approach manually, as long as it's performed completely manually. AP off - AT off.

[scandinavian13 5,192]

I'm not sure I agree with that, surely when you're concentrating on the landing it's far easier to monitor the speed rather than control it on top of all the other things you're looking at/busy doing. If you extend this logic, why not fly the approach completely manually?

 

I'm not sure how you made that jump in logic.  Not including the RA dial on an instrument approach is somehow related to turning off automation?  If anything, adding things to your scan would mean that higher levels of automation would be even more crucial for maintaining situational awareness.

 

I'm not sure if you have your IR or not, but if your scan only involves your six pack - regardless of flight phase - there's a problem.

[FL630 3]

Look at that crash with jammed throttle leaver during take off. Pilot could prevent it if he monitored performance of AT, but he fell into false sense of security thinking that AT is decreasing his workload. In fact there were one more thing to monitor than with manual take off.

 

IMO, it's completely fine to fly an approach manually, as long as it's performed completely manually. AP off - AT off.

 

I agree with your point about manual approaches entirely. The thing is though the above boils down to lack of monitoring and cross referencing. I don't know of the accident with a stuck throttle on TO, but if you're watching your IAS and N1 values, you should soon see that there is a problem with one of them. I'm not sure how we've changed from landing to take off, but on a fully automated landing, be that with a decision height or full autoland, the use of A/T surely does not increase the workload as you mentioned. It might change the style of workload, but is it not easier to monitor than to adjust and fly manually whilst monitoring other things?

 

 

I'm not sure how you made that jump in logic.  Not including the RA dial on an instrument approach is somehow related to turning off automation?  If anything, adding things to your scan would mean that higher levels of automation would be even more crucial for maintaining situational awareness.

 

I'm not sure if you have your IR or not, but if your scan only involves your six pack - regardless of flight phase - there's a problem.

 

I don't have my IR yet, no, I start next week. I didn't mention anything about the RA beyond the comment about the Turkish crash at EHAM.