Oli
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Climbing With The 727 - How?

Fri Oct 21, 2005 5:10 pm

Hi all,

I have a question. If a pilot is at a given altitude with a 727, autopilot engaged, and he/she needs to go down, or up. What is the right technique ?
1. Disengage the ALT Hold switch, then using the attitude knob of the autopilot until correct altitude is reached, then re-engaged ALT HOLD

2. Disengage the vertical guidance of the autopilot and use the trim or the yoke until correct altitude is reached, and then re-activate the vertical guidance in ALT hold mode.

Thanks for your input.

Olivier
 
bri2k1
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RE: Climbing With The 727 - How?

Fri Oct 21, 2005 8:33 pm

I can't answer the whole question, but I can tell you you're not supposed to fly with the trim. You fly with the primary flight controls and only relieve control pressures with the trim (on aircraft which still HAVE trim controls...)
Position and hold
 
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Jetlagged
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RE: Climbing With The 727 - How?

Sat Oct 22, 2005 2:00 am

It would depend on the type of autopilot installed. If it is the original type, you would use the manual pitch control to generate a suitable vertical speed. During the climb/descent manual pitch control would be used to keep the airspeed at the correct value. Adjust pitch to manually capture the assigned altitude then re-engage ALT HOLD.

Some late model aircraft do not have a manual pitch control. Instead they have a more sophisticated autopilot with pitch modes like IAS and V/S hold. You can enter the climb/descent in V/S mode with the vertical speed wheel then use IAS hold when the desired IAS is achieved. I think this type of autopilot will automatically capture the set altitude, but I'm relying on very distant memory here. If the aircraft has FFRATS as well then that can be used to set engine power automatically.
The glass isn't half empty, or half full, it's twice as big as it needs to be.
 
Oli
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RE: Climbing With The 727 - How?

Mon Oct 24, 2005 4:00 pm

Thanks for the answers!

Olivier
 
mandala499
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RE: Climbing With The 727 - How?

Mon Oct 24, 2005 6:05 pm

Ah the lovely old A/P with just "ALT HOLD" and no V/S or FLCH... not even an altitude selector...

Oli,
Using the CWS mode is the "crude lazy" method... My friends on 732s with Mode1 MCP hand fly the vertical on the way up, CWS on the way down... And yeah, don't change altitude/attitude with the trim... it takes longer to get back into trim that way... so I was told...

And when they get the Mode3 MCP (the ones like the 733), it's IAS or handfly on the up, IAS/handfly/V-S on the way down... but IAS on the way down can produce oscillation which makes the gals in the rear galley dizzy... Some even do V/S approaches (something which I don't find comfortable somehow)...

Mandala499
When losing situational awareness, pray Cumulus Granitus isn't nearby !
 
Oli
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RE: Climbing With The 727 - How?

Mon Oct 24, 2005 9:16 pm

Bas habit wit the trim!
I only do PC based simulation (with a very nice version of the 727), and I have to change that habit. Problem is that we do not feel the yoke becoming easier to handle as we trim (I suppose that pilots trim until the yoke gets easy to handle).

It is quite fun to use the 727 (very nice version of Dreamfleet) with the old autopilot.

Happy flying,

Olivier
 
bri2k1
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RE: Climbing With The 727 - How?

Mon Oct 24, 2005 9:44 pm

If you have a yoke that returns to center, you should "feel" the trim. You trim to relieve control pressures. That means, position the flight controls to achieve the desired flight characteristics. Now, are you pushing/pulling on the yoke? If so, use trim to allow the yoke to remain neutral while the flight controls stay as desired.
Position and hold
 
Oli
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RE: Climbing With The 727 - How?

Mon Oct 24, 2005 10:26 pm

The problem is that the pressure on the Yoke will stay the same whatever the trim is.
For instance, if I pull my yoke to climb at, let us say, 2000 Feet per minute, then , when I trim, I will not feel the trimming is OK in the yoke pressure, but I will have to slowly push the yoke to see if the plane us still climing at the same rate of if the rate of climb slows down. Or, I trim "up" until the rate increases a bit, that way I know this is OK and I can release the Yoke.
Some real world pilots pilot say that trimming is one of the thing that is harder in a PC simulator than in a plane (must be the only thing though!!  Wink) because there is no feeling on a PC.

Olivier

PS : sorry for my English, it is not my mother tongue.
 
bri2k1
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RE: Climbing With The 727 - How?

Tue Oct 25, 2005 1:43 am

This is probably a seperate topic, but there are a lot of things that are harder in a simulator. I use MSFS with the yoke and pedals at home to practice holding, instrument approaches, and the like. I've also been blessed to accumulate 20+ hours in full-motion Class D sims (at the UA facility at Stapleton) in the 777, A320, and 737. The 737 is the most challenging because the other two automatically trim! It's amazing to "fly" a bird as big as a 777 with less yoke pressure than it takes to park a car. But, it's still not quite the real thing, and even though I've "walked away" from engine out landings in the 777, I'd be real scared to do it in real life. Even with all the right controls and the right feel, it's just not the same as real flight.
Position and hold
 
CheckEssential
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RE: Climbing With The 727 - How?

Sun Oct 30, 2005 6:19 pm

The 727 was offered with two types of autopilots.

The more basic version has a Pitch/Roll knob, and ALT Hold switch, HDG Select (CA's HSI Only) and the ability to select NAV/LOC tracking, as well as AUTO or MANUAL G/S tracking. Also if the airplane is equipped with a GPS, some airplanes can couple to it by selecting AUX NAV.

Once the autopilot is engaged, the A/P will fly the last pitch the airplane held. You can change this by pulling back or pushing foward on the knob (like a small joystick). This will change the pitch and then when it is released, the A/P will use the cruise (slow-speed) trim to hold that setting. It isn't terribly exact and has to be monitored. To capture an altitude, you get the airplane as close to level as you can with the knob, generally 500 fpm or less. Once you reach your desired altitude, flip the ALT Hold switch and the A/P should capture that altitude.

In some of the more advanced Sperry airplanes, you will have a seperate pitch wheel instead of a knob, and a turn knob. Also it might have functions for ALT Select and HDG Select. The ALT Select function will capture whatever altitude you have set in the associated altitude alerter. Also the pitch selector has additional functions for IAS Hold, and Mach Hold. This will hold a certain Mach or IAS with varying power settings by changing pitch. It also has the ablility to do coupled ILS approaches, and be tied to a VOR or LOC signal, as well as an AUX NAV source.

Hope this helps....

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