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Post by navyman on Aug 12, 2014 10:49:29 GMT
Hello, I have read the panel handling notes re the DC9-50 panel. I found a explanation of the use of the Auto Throttle control during landing. The note also mentioned the Orange rotatable "Speed Flag"
but not how this flag is used and in what mode. Can you please explain the use of the flag.
Regards
navyman
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Post by acourt on Aug 12, 2014 15:20:46 GMT
The orange speed bug can be used as you wish. It has no bearing on what the autothrottles are doing. I use it to highlight the most important V-speed for each phase of flight. For example, I set V2 for takeoff, since all your engine out performance is predicated on that speed. For landing, I bug Vref. Doing airwork/training? Clean, minimum maneuvering speed works fine (it's about Vref+50 in the DC-9). Basically, whatever speed you need to recognize quickly is what you should bug.
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Post by aerofoto - HJG Admin on Aug 13, 2014 0:16:48 GMT
"THANKS" Al .... for that clarification. "NAVYMAN" .... go with Al's advice. He should know (better than me) since he currently drives "something" similar to the DC9 .... "IF" I recall correctly  Just a couple of general "reminders" about use of the AT compiled into these DC9 simulations whilst on the subject of its AT .... THis particular AT is only ever used for landing (the approach to the landing only) .... BUT .... not for T/O or climb, cruise, and decent .... and that's, apparently, the way the system works on the DC9 .... or on the SAS operated versions at least and which is the configuratio these particular DC9 panels are based upon. For the AT system to work .... it first needs to be engaged (on the CP sub panel) of course .... and landing speeds (calculated in accordance with the simulations weight) set in advance of it being "ENGAGED". These airspeeds are calculated and the airspeed bugs selected/adjusted .... "AUTOMATIcALY" .... only by mouse clicking upon the ASI gauge face prior to commencing the approach to landing. 1 click will provide landing V-REF for a FLAP 40 approach .... and 2 clicks will provide landing V-REF for a FLAP 50/FULL FLAPS approach .... all in conjunctio with the simulations weight. The AT system will, then, try to maintain airspeed somewhere within the computed/indicated V-REF range as is then displayed on the ASI gauge. During the approach to landing phase .... one can (and I do) set the orange ASI speed bug within this calculated landing V-REF range .... if one wishes .... BUT .... doing so does not, in any way, influence the calculated airspeed/power applications during any AT managed approach to landing. The AT system "should"  disengage .... "AUTOMATICALLy" .... upon landing, but, my own preference is to "DISENGAGE" both it, and the AT, by 100 FT prior to actually landing .... and then completing the landing "FULLY MANUALLY". I have experienced the AT maintaining engine thrust/airspeed sufficiently so as to cause the DC9 simulation/s to want to float down the RWY centerline, at around 10FT, and without allowing it descend the simulations/s any further .... since the is no auto-flare of pwer reduction phase compiled into the AT. Best (IMHO) to always disengage it/the AT .... MANUALLY" .... by no later than 50 FT prior to landing. FINALLY .... whenever landing the DC9's (or any HJG/FS supplied simulation) ensure that no more than 20% (30% at the very most) total fuel (per tank) remains, or, the simulation "WILL" be overweight for landing .... and which will, likely, result in a unacceptable pitch attitudes throughout any approach to landing. It's always best to try'n "PLAN" the fuel loading for ones intended flights so as to try'n avoid arriving too heavy Mark C AKL/NZ |
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Post by acourt on Aug 13, 2014 12:07:02 GMT
I fiddled with the autothrottles some more and have noted the following, in addition to what I mentioned in my first post:
1) You don't actually have to set the speed bugs before engaging the A/T. Once you're off the ground with the A/T engaged, the airplane will automatically slow to the computed Vref for the existing configuration. For clean configuration, it's about 190 knots. For Slats/15 it's about 160 knots. This means that, for any "non-normal" configuration for landing, using the A/T will automatically set Vref as appropriate. The downside is that you won't actually know what the target speed is unless you have the appropriate speed card. Also keep in mind that the A/T will slow to what is essentially a minimum speed. If you horse the airplane around, the A/T won't be able to keep up, and you'll end up way too slow.
2) As Mark mentioned, the A/T system on the Nine doesn't have "flare" capability, i.e. the A/T won't retard to idle automatically for touchdown (in the real airplane, you can override the A/T merely by pulling or pushing the throttles; we don't have that option in FS). If you land the airplane right, it shouldn't matter too much. The best way to describe landing the Nine is to "round out," but don't "flare." At about 50 feet, raise the nose slightly to slow the rate of descent, and hold it. Just before touchdown you can push the nose down to smooth out the touchdown (a little unnatural at first, but it makes all the difference in the world). The touchdown will be slightly firm, but also on-speed and in the touchdown zone. As someone told me..."firm touchdown means somewhere between spoiler deployment and passenger oxygen mask deployment!"
If you have the A/T and make a definite flare, the A/T will add power to maintain Vref, and you'll hover down the runway. Remember, at 140 knots, you're covering about 250 feet every second. That means in four seconds you eat 1,000 feet of runway. The Nine takes about 5,000 feet to stop comfortably. So if you're landing on a 5,000 foot runway, you have only a few seconds to put her down before it becomes critical. So I totally agree with Mark: turn off the A/T before it's time to round out.
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Post by navyman on Aug 14, 2014 15:55:06 GMT
Hi Guys,
Many Many thanks for both replies, it has cleared up some essential points for me. I love to shoot the landing at TNCM, as well as being lovely scenery it has a shortish rwy!!
Thanks again.
navyman
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Post by aerofoto - HJG Admin on Aug 14, 2014 20:58:24 GMT
"WELLINGTON" New Zealand .... the nations capital city .... is a bit like that too. A single RWY (16/34) .... 1935 X 45 meters .... and with water on both ends ....  I think I was probably slightly high on the above approach .... according to the VASI's, but otherwise, pretty well alligned. It's not so much that it's a relatively short RWY that creates any challenge/s, but rather, it's the meteorological influence/s which .... when the right combination of factors prevail/conspire .... can make operations into, and out of, Wellington a real tricky, and potentially "NASTY/INTERESTING" experience (fun for both crew and PAX alike) .... as the following videos might suggest www.youtube.com/watch?v=P_LaAkAyoz0www.youtube.com/watch?v=JfS4X-xF_Y0Welligton is located at the extreme bottom end of New Zealands North Island .... right on the edge of the Cook Straight which separates the North from the South islands of New Zealand. The weather .... particularly the wind gust factor gets notoriously worse the further south one heads toward the roaring 40's .... and we're located more-or-less on the edge of that zone/region. What happens is the weather .... which is predominantly westerly .... screams across the Tasman Sea, from Australia, and is then squezed between this natural geographic gap/vent (Cook Straight) between both islands .... hence the "particularly violent" turbulence/conditions that can, and do, result  Even so .... AIR NEW ZEALAND DC8-52's were once based in Wellington during the late 1970's and early 1980's .... and both the B747-100B/200B and B777-300ER have both operated into WEL/NZWN too (the B741 was a UAL fuel emergency when Auckland/AKL/NZAA was fogbound .... as was Christchurch/CHC/NZCH .... along with the usual circumstancial diversion which is RNZAF base Ohakea/OHK/NZOH too .... leaving only Wellington available) as diversion trials/excercises, but, in the case of both the latter B747/B777, and former DC8 operations also, each of these aircraft were "weight restricted" in order for the RWY to be able to accomodate them safely. GETTING OFF TOPIC A BIT HERE NOW .... I know .... but .... the following video presents a little about the AIR NEW ZEALAND B747-200B´s .... when we operated them .... including (near the end) a short segment in regard to the airlines diversion trials with these aircraft into WELLINGTON .... www.youtube.com/watch?v=yvJjVlqu9YoDuring more recent times AIR NEW ZEALAND has also conducted similar "diversion trials" (only) into WELLINGTON using the B777-300ER too We got the aircraft "IN" OK .... www.youtube.com/watch?v=ahok2vLA8uE.... AND .... we even got it out again also .... www.youtube.com/watch?v=yTJgjs7zG4IMark C AKL/NZ |
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disengage .... "AUTOMATICALLy" .... upon landing, but, my own preference is to "DISENGAGE" both it, and the AT, by 100 FT prior to actually landing .... and then completing the landing "FULLY MANUALLY".