Hi Mark,
I assume that was 280 kias when you started your decent? Mine always seems to speed up once I start my decent, probably because I don't bother to slow down before starting the decent. That's what led me to my conversation with Lou about using inflight spoilers. You read that. Adding to realism as it was "back in the days", can you turn your GPS off so you can't see the GS? But it sounds like the approach you described was almost spot on. That's great.
I would like to get approach charts as well. FSX doesn't give you much vertical information in the flight plans. As an example: I did a flight from Spokane, Washington, KGEG (USA) to KSEA. Following the 3:1 rule in starting the decent and maintaining 2200 fpm at 300k, I would have crashing into the Olympic Mountain Range just East of Seattle if I hadn't been looking at my radio altimeter. I did follow altitude assignments as per the flight plan. And I did find myself using spoilers to keep the 707 slowed. Next 707 flight I do I'll try slowing down before the decent as Lou suggested.
So yes, some more accurate approach charts would make this a lot more realistic and take the guess factor out if it.  There's just not enough information provided by Microsoft. What do you think?

LOU wrote on Jul 1^st, 2011 at 6:21pm:
I can't believe it! Why the heck was I not thinking of the fact that at high altitude I use Mach and not KIAS! Doh. I feel like a complete dunce. It must be because of my current pain relief medicine! It is not allowing me to think straight. Hey! I gotta blame someone/something.

@Brian. All speeds were KIAS.

Mark

Hey Mark,

Try this reading with your current drug status... It could induce glazed eye syndrome.  

http://www.tscm.com/mach-as.pdf

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In the 727 the Mmo ( Mach maximum operate ) is .89, pretty fast for a 60's type jet. The reason for the limit is that parts of the wing will go faster than Mach 1.0. When I was an instructor, we would take the students back it the cabin on a training flight and show them the wing at around Mach .89. You could see the shock wave on parts of the wing as that part of the wing approached Mach 1.0. This is a time when we actually used real planes to train pilots. Fuel was 11 cents a gallon back then.  

This drawing shows how some parts of the wing can be at Mach 1.0 while other parts are slower. As you approach the max Mach for the plane you get a buffet that is called Mach buffet. It is similar to the feel of stall buffet. As you climb higher you approach an area called "coffin's corner" where stall buffet and Mach buffet come together. As you can tell by its name it's a place to avoid.  

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Here is a bit more detail from Joseph Michael Lamonaca, Esq, ATP FAA Lead Safety Rep.

Aircraft climbing at a constant IAS will have an increasing TAS, Mach number is a more precise indicator of speed at the flight levels. The mach meter measures the airspeed of an aircraft relative to the speed of sound. It's basically made up of an Air Speed Indicator and an altimeter. It also has a sealed capsule containing ISA conditions and a pitot pressure sensor inside an (free air ) static pressure sensor. No temperature sensors are present in a machmeter because it uses the formula Mach Number = dynamic pressure. Since airspeed off an ASI must be corrrected for nonstandard temperatures and pressures, Mach is a truer indication of airspeed.

During climb jet aircraft generally conform to a schedule which specifies an initial climb speed as an indicated airspeed (IAS), and a Mach number for the upper part of the climb until cruise altitude is reached. Mach numbers are then used as a cruise schedule. The pressure altitude (FL) at which the IAS climb schedule ends and the climb Mach number schedule starts is called the "Changeover Level".

In the early stages of the climb at a fixed IAS, the Mach numbers rise until changeover level is reached. Changeover level is that flight level where the climb IAS value and climb Mach values occur simultaneously. For any given IAS/Mach climb schedule there can be only one changeover level. Different aircraft types may have different climb schedules specified in their Aircraft Flight Manual. (AFM).

When dealing with two aircraft at the same level, assigning the same IAS or Mach number will produce the same TAS. Mach numbers are normally used for this purpose at fairly high levels (FL250 and above). Mach 1 ranges from about 600kts TAS at FL250 to 572kts TAS at FL350. As a general rule of thumb at these levels 0.01 Mach equals 6 knots TAS. Mach 0.80 at FL290 will produce the same TAS as Mach 0.83 at FL370. This arises because the speed of sound is slightly less at FL370 than it is at FL290.

If a controller is trying to match speeds of aircraft at different levels, the same Mach number will mean that the higher aircraft will be a little slower.  An allowance of .01 Mach for every 2000-3000 feet level difference will achieve a closer match. Unlike Mach number control, the results of allocating IAS restrictions to aircraft vary substantially with altitude. An aircraft maintaining 280 knots IAS at FL370 will have a TAS of 459 knots while at the same IAS at FL270 will produce a TAS of 417 knots.

For aircraft operating at the same IAS, a rule of thumb is 7 knots for every 1000 feet level difference. The result of this is when two aircraft are assigned the same Mach number, the higher aircraft will be slower, however, when they are using the same IAS the higher aircraft will be faster. Above FL240 each 10 knots of IAS equals approximately 15 knots of TAS.

Using the more precise Mach number also allows for reduced longitudinal separation minima, according to the ATC handbook. This is obviously a benefit on high volume air traffic routes.  

Mark, when your drugs are finished, the article talks about just that - when to use Mach.

If I remember, each plane has a different proper altitude. I think in the 707/727 we used FL 280 to 300 to make the change.

Lou

LOU wrote on Jul 1^st, 2011 at 6:21pm:


As an addition to Lou's info, using time-speed-distance, any two will give you the third. You can also still buy a 'wizzwheel' (E6B) which will help with that as well as a lot of other things, if you REALLY want to get 'real'.

Time to park the 757 and get back into the 707 for awhile, Lou's posts have that affect on me!