Several questions about the 737 NGX cockpit

[Boeing_Driver 76]

Hello,

After going through the tutorial #1 several times, I've found a few things I'm having difficulty finding:

1. Where is the C/R (cancel/recall) MFD button located?

2. Where is the TRC button located?

3. Where is the bank limiter selector located?

4. Where is the brake pressure gauge located?

5. How does one determine OAT in the air?

6. How does one shorten the distance for the 'Total Distance' on the Pushback page?

 

Thanks in advance,

Brian

[scandinavian13 5,192]

2 minutes ago, XLS_DRiver said:

1. Where is the C/R (cancel/recall) MFD button located?

Above the upper EICAS display, labeled "C/R."

If you cannot see it, then you might have skipped over the strong warning in the beginning that says "fly this using the default PMDG livery, or the instructions may not match up." The reason for this is the aircraft options discussed in the Intro Manual.

2 minutes ago, XLS_DRiver said:

2. Where is the TRC button located?

TRC? Page reference?

If you're referring to the TFC button, it's in the center of the EFIS Range knob, labeled "TFC."

6 minutes ago, XLS_DRiver said:

3. Where is the bank limiter selector located?

Outer edge of the heading selector on the MCP.

I don't recall this being mentioned in Tutorial 1.

7 minutes ago, XLS_DRiver said:

4. Where is the brake pressure gauge located?

Next to the gear handle and gear position lights, labeled "BRAKE PRESS."

10 minutes ago, XLS_DRiver said:

5. How does one determine OAT in the air?

N1 LIMIT page, among other places, but I'm assuming that's what you're asking for, specific to the tutorials.

12 minutes ago, XLS_DRiver said:

6. How does one shorten the distance for the 'Total Distance' on the Pushback page?

Can't shorten the overall distance. You can shorten the straight leg distance. The overall distance is initial push distance + turn radius.

[Spin737 102]

We don't typically use OAT in the air. It's usually SAT and TAT.

[kevinh 409]

SAT and OAT are effectively the same thing.

[Spin737 102]

1 hour ago, kevinh said:

SAT and OAT are effectively the same thing.

You're right - it's semantics. But the gauges (and Limitations) say "SAT" or "TAT" and people get confused on which is which sometimes. Eg:

I was flying in to PANC one afternoon and the pilot I was flying with was surprised to see snow. "It's 5C and it's snowing?!?" I told her, "That's TAT and it has ram rise. Check out the SAT. It's -2C." Mystery solved.

[kevinh 409]

Just to confuse things the VC10 had an OAT gauge on the F/E panel. I was designing software for a VC10 full flight sim and assumed it would indicate SAT, as it would on any normal aircraft. No, a VC10 F/E told me, it indicates something between SAT and TAT. Apparently the OAT temperature probe had some ram effect, but there was no data to show how much. I don't suppose it was designed that way, it just was how it was.

Edited October 16, 2018 by kevinh

[skelsey 765]

My understanding is that temperature probes on modern aircraft are TAT probes and the SAT is then calculated from this sensed temperature. Logically this makes sense as the SAT is the temperature of the undisturbed air that the aircraft is about to fly through, so directly measuring that with a probe attached to the aircraft would be rather problematic!

The percentage of the ram rise sensed by the TAT probe is known as the 'recovery factor' - a recovery factor of 1 would indicate a 'perfect' instrument which accurately senses all of the ram rise and therefore indicates the exact TAT, whilst a recovery factor of 0 would indicate a probe which senses none of the ram rise (i.e. indicates SAT).

Modern probes have recovery factors very close to 1 -- this was probably not the case in the days of the VC10!

Although the TAT probes used on modern jet transports are very good at measuring air temperature (ie they are largely unaffected by the heating effect of the sun, for instance) the drawback is that they do require air to be flowing through the probe to obtain an accurate reading, and so they are less accurate on the ground, for instance, unless they are artificially aspirated in some way.

[MarkJHarris 128]

Some 737s have Aspirated sensors and most don't. It was an option.

The 737 was my first aircraft that did not have a de-iced tail. Got me a little un-nerved at first. Then a wise man told me a little story, and it not only set me straight, but has stood me in good stead.

Ice mostly occurs close to the freezing point. In reality, you'll ice up flying in cloud with a SAT of 0' to -15' with considerable less chance of picking anything up below that. The TAT indicated the temperature of the leading edges. So, if you're descending through icing conditions.....

 

...speed up!

 

I do this and it's perfect. 280kts IAS gives me a temperature of about +8 or +9 going through -15'SAT. I can then slow up as i descend towards 0' SAT and once through the freezing level slow right back to approach speed. 

I have never used the airframe ant-ice with this method and other than the inevitable ice on the fin in the dead spot near the root, never have a problem.

 

Some F/Os get it, some struggle. It works for me! 

 

[Andrea1 6]

Hi,

I'd like to add the maths formula (temperature in Kelvin degree): TAT=SAT*(1+0,2*(Mach)^2) so i.e. if you're flying at 0,78 Mach with a  SAT of -56°C (217 Kelvin, your TAT will be: 217*(1+0,2*(0,78*0,78))= 217*(1+0,12168)= (about) 243 kelvin= -30°C..

Ciao

Andrea Buono

[skelsey 765]

For a more pilot-friendly formula:

SAT = TAT - (V/100)²

Where V is TAS in knots and the SAT and TAT are in degrees Celsius 😉

[Stearmandriver 2,205]

Or...   Progress page 2.  Read the SAT.  Why not let the computer do the math for you? ;-)