When flying an ILS approach my understanding is that most rw NG pilots disconnect the A/P when they have the runway in sight but when do you normally disconnect the A/T? And if doing an autoland do you need to manually disable the A/T at some point or will this happen automatically? Same thing in the real bird as in the NGX?

 

After been using a CH Yoke an CH Pedals for many, many years I'm now trying out my son's Saitek controllers he doesn't use anymore and even if it's far from PFC quality it still feels a bit new and fresh to me and especially having a separate throttle quadrant. I have both the yoke and the pedals set up, controlled and calibrated using FSUIPC.

 

So far I've always used a method where I have both the A/P and A/T enabled during the approach and then when I have the rwy in sight or usually at approx 1000 feet I disconnect the A/P but keep the A/T enabled. Then when I'm about 100-50 feet above the runway I disconnect the A/T. I've also had the 'A/T Manual Override' option set to 'Never' but changed it now to 'In hold/arm mode only' as per the recommendation in the NGX doc trying to fly the NGX as close to how it's done IRL as possible now with my new gear.

 

How are you guys doing your approaches and how have you set up your HW to mimic real world ops as close as possible?

Boeing recommends the A/P and A/T to be disconnected together at the same time. There are quite a few threads on this subject already (in fact, there's one on the first page right now: http://forum.avsim.n...isual-approach/), so some searching around will likely provide you with additional information.

 

Personally, I disconnect both of the Otto siblings between 1000' and 500' AGL, provided the runway is in sight. It helps to have the "Show Thrust Lever Pos" option (found under PMDG Options -> Simulation -> Pg. 2) set to "On" or "When Moving", so that you can match your physical throttle position with the current N1 power setting just prior to disconnecting the A/T. That way, you won't be experiencing big surges or drops in power because of a throttle setting mismatch.

 

Oh, and during an autoland, the A/T disengages automatically 2 seconds after touchdown (see FCOMv2 4.20.10).

 

Good luck!

Great, thanks a lot!

I also used to disengage the A/P at glide slope interception and the A/T at 100 ft, but ever since I was notified of Boeing's strong recommendation, I have tried to disengage both simultaneously.

 

However, on approaches where glide slope interception occurs far from the airport, I will disengage the A/P but leave the A/T engaged until the aircraft is in landing configuration, thus reducing workload. Once the aircraft configuration has been finalized, it is easier to find the thrust "sweet spot" that will require the fewest corrections.

 

Also, as the aircraft nears the airport, more aileron/elevator corrections may be necessary in order to maintain the proper descent path, thus making more use of the "thrust demand anticipation" benefits of manual thrust control.

It helps to have the "Show Thrust Lever Pos" option (found under PMDG Options -> Simulation ->

 

I fly mostly GA in FSX, including a couple of private/business jet models. I sure wish this feature was present in the small jet models I fly. I usually have to disengage A/T as I am adjusting speed on approach, well before final. Otherwise if I wait until short final I most often get big surprises that give birth to missed approaches.

usually, i fly the whole approach from about 10000 feet by hand. As well as holdings and everything else that would require me to use my mouse.

usually, i fly the whole approach from about 10000 feet by hand.

 

I do this with GA models in VFR conditions, including MVFR. Of course even in IFR conditions near minimums with typical GA singles and twins the power and speed control is always manual, and those are the critical elements of the approach.

Depends on the weather but usually once I'm established on the approach and have the runway in sight ill disengage and fly it in. It's the only time I get to "fly" a 737 may as well take advantage.

I also used to disengage the A/P at glide slope interception and the A/T at 100 ft, but ever since I was notified of Boeing's strong recommendation, I have tried to disengage both simultaneously.

 

However, on approaches where glide slope interception occurs far from the airport, I will disengage the A/P but leave the A/T engaged until the aircraft is in landing configuration, thus reducing workload. Once the aircraft configuration has been finalized, it is easier to find the thrust "sweet spot" that will require the fewest corrections.

 

Also, as the aircraft nears the airport, more aileron/elevator corrections may be necessary in order to maintain the proper descent path, thus making more use of the "thrust demand anticipation" benefits of manual thrust control.

Just keep the AP in. When ready to disconnect, disconnect the AT first, because then you will get the thrust levers in the position that produces the right amount of thrust for the configuration and the approach. Then disconnect the AP.

 

If you want to disconnect earlier, then better to disconnect both in the same sequence. To make hand flying a doddle, you just need some approximate pitch and power settings so you can adequately estimate a good N1% starting figure and a reasonable pitch attitude for your configuration, then small adjustments. The basic information is in the Performance Inflight, Unreliable Airspeed section of the QRH.

 

Alternatively, fly the HUD, it gives really precise and intuitive speed, energy and flight path indications that make hand flying an absolute hoot and doddle.

Lots of great input and advice, thanks for sharing guys!

For the longest time, with all the PMDG heavies like the 747 and MD-11, I used to disengage autopilot around 1500 ft AGL but I left the auto throttle on until flare. My thought on the the subject at the time was that without the sensory stimuli and force feedback on the yoke like in the real world, and with the narrow field of vision in a sterile environment, I could not trust myself to keep the speed up within an acceptable margin during finals if I was constantly playing with the throttles by hand. I was also under the impression that it was the auto throttle's job to make my life easier as it would respond quicker and more accurately to changes in winds or flight control movement. After some research on the subject, and with the release of the NGX, I decided to learn to apply proper hand flying technique, which meant a/t off at the same time as the a/p is disabled. Took some practice, but it just feels right. I regret not doing this with the MD-11 and Queen, as looking back it now feels like I have cheated. I used to think that hand flying down to flare was something for the Cessna flyers, but it's very important to use these basic skills in all aircraft, no matter the size or automation capability on offer.

It usually depends on the workload but I normally have it off for sure by the time the jet is established on the ILS.

I normally disconnect alongside the autopilot. However today I tried leaving the autothrust on whilst flying manually and it kept my speed pretty good! I disconnect the autopilot once I'm completely stabilised on the approach with the VREF selected in the MCP. Generally works out 4 to 10 miles on the glide path!

 

In the RW I think a lot of airlines vary - some you actually can't disconnect the autothrust at all so I've heard.

I normally disconnect alongside the autopilot. However today I tried leaving the autothrust on whilst flying manually and it kept my speed pretty good! I disconnect the autopilot once I'm completely stabilised on the approach with the VREF selected in the MCP. Generally works out 4 to 10 miles on the glide path!

 

In the RW I think a lot of airlines vary - some you actually can't disconnect the autothrust at all so I've heard.

Rather than airline specific, it is generally a type specific SOP. As mentioned, if you increase or decrease thrust on a real 737 without controlling the pitch, it will pitch up or down significantly. This effect is so great, that it can be impossible to recover from a steep nose up situation with high thrust. Obviously then, not managing the thrust levers yourself has the potential to throw you a curveball. NGX does not replicate this dynamic, but if you want to keep it real...

 

However, in a 777, because it is fly by wire and auto correcting, there is no need to disconnect the AT regardless of the phase of flight and AP status. One large airline, for example, the AT remains on from T/O to rollout. The AP from 50' to minimums.

I saw a Westjet 737 DVD the other night from what I gather they were disconnecting auto-throttle about 200-100ft above before landing.

Autopilot was disconnected about 1000-500ft above.