SAAF

Touch and Go Problems

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Good Day All,

I have been flying a few circuits in order to better acquaint myself with the "Queen".

Upon touch down, I advance my throttle to 50%, press TOGA and advance the throttle to 100%. However nothing seems to happen, the blue marks on the N1-Column clearly show the throttle position as advancing yet the Autothrottle remains in idle, I try moving the throttle around yet the Autothrottle keeps on bringing the thrust levers back to Idle.

Am I simply following the wrong procedure or have I incorrectly set the aircraft up?

(My A/T Manual Override settings are Hold mode only)

 

Thanks for the assistance.

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On a touch and go, no speed brakes armed or auto brakes. Assuming your visual, upon touchdown, no reverse, go to Flaps 20, stand up the thrust levers to vertical, about 50% for spoolup, reset the trim in the green band and, when trim is set, manually advance the thrust levers to about 80 to 90% of max thrust, rotate at VREF, and pitch 15 - 18 depending on weight, assuming light weight, at 400 feet, push TO/GA, make sure your FD is on, HDG SEL, at 1000 feet, FLCH Speed190 or 200, retract flaps to 5, level off pattern altitude (1500 AFE), turn crosswind, wings level momentarily, turn downwind, then on with a VFR traffic pattern or vectors or whatever.

Dont use TO/GA on a T&Go, manual thrust only. Usually with a crew, the PF has specific duties and the PM has specific duties and call outs, but Flight simming, we do it all. This is the real jet procedure for this. Once airborne, you don't have to use the FD's, you could do it all raw data if desired, but typically, if available we use them after liftoff. Hope that helps...

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As Alex says -- TOGA is inhibited below 5R, so you have to use manual thrust.

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The other issue may be that you are doing a touch and go from an auto land. Touch and go's are normally done as visual maneuvers and on final you would be manual flying and manual thrust. If you are doing from an auto land, disconnect the A/T on short final, and retard to idle at 25 feet, then after touchdown , disconnect the A/P and continue with the procedure. This is not normal, but it sounds like the A/T is going back to idle on you, when in reality it should disconnect when you go into reverse. But on a T & go we don't want reverse, in fact if you go to reverse, no Touch and Go, it is called off.

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Quote

Upon touch down, I advance my throttle to 50%, press TOGA and advance the throttle to 100%.

The TOGA button should not work in this situation. On touch down, TOGA is disabled. It won't re-arm unless the airspeed is below 50kts (even then, the throttles may not have time to move to takeoff power before thrust hold is achieved). This is why manual thrust is required.

 

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Thank you all for your help. It seems my understanding of the T&G procedure in the 744 was flawed as I was using Autothrottle for the entire circuit.

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I'm trying to follow the proper procedures for touch and go circuits and found this thread with some great advice.  My question is how to program the FMC with helpful waypoints or paths corresponding to a proper pattern with, say, a downwind leg offset 2nm from the runway and the "perch" (start of base turn) at 45 degrees offset from the landing threshold.


Can this be done with abeam points or dme arcs or some other method?  Basically I'm just looking for some flight path guidance for the vfr pattern so I don't have to "eyeball" when to turn and to be on the downwind leg at a proper offset parallel from the runway.

Thanks for any advice!

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54 minutes ago, captain_adf said:

Basically I'm just looking for some flight path guidance for the vfr pattern so I don't have to "eyeball" when to turn and to be on the downwind leg at a proper offset parallel from the runway.

Well, a 2 nm downwind leg is fine for small GA aircraft, the normal radar downwind is 5 nm.  I put a 5 nm circle around the airport for guidance. 

As far as when to turn base, I usually have an ILS selected even if I am flying a visual approach and use the fixes on it to just my turn to base and final.  The ND gives you all you need without programing pseudo waypoints.

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Is it possible to setup a circle around the landing threshold, not just the airport?  I'll definitely select an ILS approach to get the extended centerline.


Here is an illustration of what I'm trying to do from one of my favorite websites:

http://code7700.com/1986_traffic_pattern_geometry.htm

I would love to be able to program that exact pattern into the FMC.  I agree a 2nm offset is really tight for a 744, but if the Air Force can do it, so can I :)

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You are paying too much attention to things that don't matter.  Your goal is to learn how to fly the aircraft in the local pattern, not how to program a computer to give you a pretty picture.  You don't need to sweat the small stuff, like is the downwind 2 nm or 5 nm or even 10,  You'll find a 2 nm downwind will force you into a near constant arc instead of a turn to base then turn to final.  Learning to fly the constant arc base and final is how the Navy flies ahaha.  It's a lot harder than a well defined base leg.

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As Dan says, the clue is in the name -- VFR -- i.e. visual. The aim is to spend more time looking out and less time staring at a magenta line.

That said, as has already been mentioned given the limited view out of a 747 flight deck (and even more so in the sim) it certainly doesn't hurt to use the ND as a guide, particularly in terms of judging the radius of turn on to final.

Rather than aiming for a specific distance as such the more common method is to time the downwind leg: at 1500ft AGL and circa 180 kt, 45 seconds from abeam the landing threshold (corrected by +/- one second per knot of headwind or tailwind) gives you around 2-2.5NM spacing which is roughly what is recommended in the FCTM. You can use the ND to help in judging your downwind spacing and tracking (set the range to 5nm and the runway symbol should be about halfway across the display for a 2-2.5nm downwind spacing. If you're flying the circuit above 1500ft AGL you can add 15 seconds per 500ft to the basic timing.

As far as my knowledge goes I have to say it is more common from what I have seen to fly a constant aspect circuit in large jets than it is to fly a "square" traffic pattern (probably because squaring off the crosswind and base would likely result in an excessively wide circuit at jet speeds) but that is not to say that it is wrong or impossible. 2nm is not that tight; it is in line with the FCTM recommendation for visual circuits.

Radar/instrument circuits are a different matter and generally involve being vectored to a much wider pattern/longer final to practice an ILS or other instrument approach.

Main tip -- don't fly excessive speeds! Certainly I wouldn't fly any more than about 180kt at any point in the circuit and quite possibly much less than that; the Big Airline certainly used to routinely fly base training circuits in the 744 at Ref +5 all the way around. Give yourself half a chance!

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