A couple of MD-11 Questions

[JHepburn 0]

A few quick questions on MD-11 behavior...1. When to arm ATS: Is it acceptable to push the Autoflight button on the ground at any time during taxi? My understanding is that this arms the ATS, but I'm unsure if it does anything else... (like set a reference to current heading)2. Related to #1: I have noticed on several occasions that I select a heading that requires a right turn immediately after takeoff (at the MM, e.g.) , pull the heading button, and the plane turns left rather than right. This has happened on numerous occasion and usually solves itself after a Direct-To or some other action3. Trim down during approach: I hand flew an approach and landing this afternoon and got an uncommanded pitch-down at about 1000AGL. It happened during a test flight where a couple of previous go-arounds had been completed. Basically, I was hand flying a visual approach and received an aural "stabilizer motion" with no trim input around 1000AGL followed by the need for full back deflection of the yoke to maintain the glideslope. Any ideas what caused this?4. Go around procedure: Perhaps I missed it in the FCOM, but is there a detailed explanation of what to expect (and how to handle) a coupled as well as hand-flown go around? Thanks!

[Mace 1,902]

A few quick questions on MD-11 behavior...1. When to arm ATS: Is it acceptable to push the Autoflight button on the ground at any time during taxi? My understanding is that this arms the ATS, but I'm unsure if it does anything else... (like set a reference to current heading)

Yes, pressing Autoflight while in taxi arms the autopilot. This appears to be normal procedure.

2. Related to #1: I have noticed on several occasions that I select a heading that requires a right turn immediately after takeoff (at the MM, e.g.) , pull the heading button, and the plane turns left rather than right. This has happened on numerous occasion and usually solves itself after a Direct-To or some other action

I have noticed the MD-11 occasionally begin turning the opposite direction, but then quickly recovers and begins turning the correct direction. I noticed this leaving MPTO the other day, for a northerly departure SID. If your is not recovering quickly then I have no explanation other than possibly the FMC is programmed incorrectly. There are limits as to the turn radius that the aircraft can phsyically undertake, so you should take that into consideration when creating your plan, particularly around transitions.For instance, if you program in a 145 degree turn around a waypoint, good luck getting the aircraft to make that turn with any accuracy, even at an low airspeed (<250 KIAS).

3. Trim down during approach: I hand flew an approach and landing this afternoon and got an uncommanded pitch-down at about 1000AGL. It happened during a test flight where a couple of previous go-arounds had been completed. Basically, I was hand flying a visual approach and received an aural "stabilizer motion" with no trim input around 1000AGL followed by the need for full back deflection of the yoke to maintain the glideslope. Any ideas what caused this?

Possibly a downdraft. I do not know what your setting is in FSX weather menus, but this can be turned on or off.

[Guest FinMD11]

1. When to arm ATS: Is it acceptable to push the Autoflight button on the ground at any time during taxi? My understanding is that this arms the ATS, but I'm unsure if it does anything else... (like set a reference to current heading)2. Related to #1: I have noticed on several occasions that I select a heading that requires a right turn immediately after takeoff (at the MM, e.g.) , pull the heading button, and the plane turns left rather than right. This has happened on numerous occasion and usually solves itself after a Direct-To or some other action

1. At least on Finnair birds, ATS is engaged when advancing throttles to TO thrust. As the commander advances throttles he calls "select autoflight" to engage the ATS, which then takes over. Arming the ATS could be hazardous if for whatever reason you have to advance the throttles all the way up where ATS kicks in. Not a likely scenario, but still. :)2. Have you made sure that the HDG bug dashed line along the compass arc on ND is to the right direction? To ensure the HDG bug is lined up with the aircraft during TO is by pressing the HDG select knob when lined up on the runway.Hope I could be of any help!

[mburkhard 23]

1. At least on Finnair birds, ATS is engaged when advancing throttles to TO thrust. As the commander advances throttles he calls "select autoflight" to engage the ATS, which then takes over. Arming the ATS could be hazardous if for whatever reason you have to advance the throttles all the way up where ATS kicks in. Not a likely scenario, but still. :)

This might be hazardous on a desktop simulator but it is not on the real aircraft. ATS does not pull the thrust levers out of your hand. You'd feel if ATS would engage and try to give more thrust than you command, but having your hand on the levers will block them right where they are.Regards,Markus

[Guest FinMD11]

This might be hazardous on a desktop simulator but it is not on the real aircraft. ATS does not pull the thrust levers out of your hand. You'd feel if ATS would engage and try to give more thrust than you command, but having your hand on the levers will block them right where they are.

Markus,Yes, I was quite well aware of that. :) Actually that applies also in the sim if you select "Thrust levers override ATS" (or what ever it's called in the PMDG menu), but I guess that ATS intervention during taxi would be something unwanted in real life or in the sim, regardless of whether or not you have the control over the thrust levers... :) My point was only that in Finnair operations ATS is not engaged until on the runway AFAIK.

[JHepburn 0]

2. Have you made sure that the HDG bug dashed line along the compass arc on ND is to the right direction? To ensure the HDG bug is lined up with the aircraft during TO is by pressing the HDG select knob when lined up on the runway.Hope I could be of any help!

Thanks Anssi, I will check the dashed line. Any thoughts on what would cause the dashed line to "go the long ways around"?Rhett, the initial turn after takeoff was done in heading select (i.e. I dialed the heading and pulled the knob). I'm not sure FMS programming _should_ have any bearing, but I suppose it's possible.

[Guest Totalbeginner]

but I guess that ATS intervention during taxi would be something unwanted in real life or in the sim, regardless of whether or not you have the control over the thrust levers...

ATS doesn't engage until at least 75% N1. You'd have to be doing something pretty non-standard to warrant such a high power setting during taxi.

[Check_Airman 3]

1. To guard against the potential problems mentioned above, I press AUTOFLIGHT as I enter the runway.2. The dotted line shows the direction in which the plane will turn. Turning the knob to the left/right will cause the AP to turn in that direction, even if it is the long way round.

[JHepburn 0]

1. To guard against the potential problems mentioned above, I press AUTOFLIGHT as I enter the runway.2. The dotted line shows the direction in which the plane will turn. Turning the knob to the left/right will cause the AP to turn in that direction, even if it is the long way round.

Aha!! Thanks Check!The issue is that I typically set runway heading or expected departure heading either pre-pushback or during taxi. My guess is that I've just dialed around the wrong way...thanks!Now, does anyone have any advice for FCP and ATS management during GA?

[stevenp 1]

I set up ATS right when I get my engines started. You really don't need to get the throttles at 75% N1 to taxi. Once you get on the runway put her up to 80% and let er rip.

[Guest]

ATS doesn't engage until at least 75% N1. You'd have to be doing something pretty non-standard to warrant such a high power setting during taxi.

I set up ATS right when I get my engines started. You really don't need to get the throttles at 75% N1 to taxi. Once you get on the runway put her up to 80% and let er rip.

I've got a little and sensitive throttle control on my joystick... so I always press AUTOFLIGHT after lining up for take off... better safe then sorry. :( I see no reason why I should do it earlier btw: what'a the use of doing it earlier...?