Newbie Question about FMC error "Unable ??? KTS at "waypoint

[sloppysmusic 224]

Would help more if you said not what you are trying to do but what you are trying to ACHIEVE. Different things! Yes it can be confusing but plenty of help here.

IF you are just trying to descend faster because you are in a hurry safest way is to go to the CDU and press:

INIT REF

INDEX

PERF

and enter a higher number into the COST INDEX bottom left (LSK5 in CDU speak!)

maximum 500 I believe for 737. You CAN do this at all stages of the flight, and the plane will slow down correctly most of the time when you need it to for approach plus will not go too fast. When practicing and learning though it is better to set a LOWER number even as low as 10 so the plane gives you time to learn all the routines which come fast when approaching final! 

(Entering speeds manually is usually only done when the CDU SID or STAR has errors and you want to fix them.)

You CAN speed up by using the SPEED dial (which turns off VNAV control of speed) but you can end up going too fast this way if you dont remember to slow down the same way as the plane will keep trying to do that speed until you land (hit the ground!).

The Tutorial flight is indeed your friend! Plus lots of practice.

 

[Stearmandriver 2,271]

4 hours ago, DaveCT2003 said:

Remember, the Flight Management Computer (FMC) is a black box that sits in the aviation bay in most airliners... no way to operate it even if it was on the flight deck.  The CDU is the pilots interface to input, select and output information from the FMC. Why is this important?  Terminology is everything in our hobby... 

I've seen this point raised quite often on flight sim forums (I'm not picking on you in particular, promise).  I just thought you might be interested to know that in the real world, almost no pilots use the term "CDU".  Yes, what you say about the difference between the FMC and CDU is 100% correct, but the only time I've ever referenced (or seen someone else reference) a CDU is when talking about something very specify to that box; for instance, a maintenance write-up ("EXEC key on left CDU inop"). 

When talking about programming or modifying route or performance data, it's always referred to as, "I changed X in the FMC."  "Could you pull up the HAWKZ7 to ILS16R in the FMC?"  "Enter a 300kt descent in the FMC."  "Check the legs page in the FMC."  Etc.  No one talks about doing anything on or in the CDU. 

Note: a caveat.  It occurs to me after writing that, that I can only speak to common phraseology in the states.  Perhaps this is different elsewhere. 

[DaveCT2003 1,820]

37 minutes ago, Stearmandriver said:

I've seen this point raised quite often on flight sim forums (I'm not picking on you in particular, promise).  I just thought you might be interested to know that in the real world, almost no pilots use the term "CDU".  Yes, what you say about the difference between the FMC and CDU is 100% correct, but the only time I've ever referenced (or seen someone else reference) a CDU is when talking about something very specify to that box; for instance, a maintenance write-up ("EXEC key on left CDU inop"). 

When talking about programming or modifying route or performance data, it's always referred to as, "I changed X in the FMC."  "Could you pull up the HAWKZ7 to ILS16R in the FMC?"  "Enter a 300kt descent in the FMC."  "Check the legs page in the FMC."  Etc.  No one talks about doing anything on or in the CDU. 

Note: a caveat.  It occurs to me after writing that, that I can only speak to common phraseology in the states.  Perhaps this is different elsewhere. 

I hear you, but my point was about searching documentation.

That aside, I can tell you that we did call them that in the military (prone to being technically accurate). I'm extremely familiar with commercial pilot training (no insult, I promise) and I'm far from surprised at what you say.  Shoot, we both know the training progressive for guys who were purely trained from GA to commercial, right?  Scary, Scary.  Chief Pilots never certified on the aircraft their the Chief Pilot of (rampet in the industry, especially with regional airlines) and, well, I could go on for hours and hours.

Not saying their aren't fantastic pilots who were trained outside the military, their certainly are.  Cream always rises to the top.  I'm talking about the training not the person/pilot, and pressure on regulators for help cutting costs (including training), non-structured, self paced training being used today, etc.

 

EDIT: Something else occured to me.  Often time one hear's it said that "I'll enter that into the FMC", which is TECHINICALLY accurate.  It's done VIA the CDU, but it's entered into the FMC.  This may be a point of confusion.

But I'm interested now, so I 'm going to contact a friend at Boeing's Training Center and ask some questions about this.

Good conversation!

 

Edited November 17, 2018 by DaveCT2003

[wheels1911 1]

5 hours ago, sloppysmusic said:

Would help more if you said not what you are trying to do but what you are trying to ACHIEVE. Different things! Yes it can be confusing but plenty of help here.

IF you are just trying to descend faster because you are in a hurry safest way is to go to the CDU and press:

INIT REF

INDEX

PERF

and enter a higher number into the COST INDEX bottom left (LSK5 in CDU speak!)

maximum 500 I believe for 737. You CAN do this at all stages of the flight, and the plane will slow down correctly most of the time when you need it to for approach plus will not go too fast. When practicing and learning though it is better to set a LOWER number even as low as 10 so the plane gives you time to learn all the routines which come fast when approaching final! 

(Entering speeds manually is usually only done when the CDU SID or STAR has errors and you want to fix them.)

You CAN speed up by using the SPEED dial (which turns off VNAV control of speed) but you can end up going too fast this way if you dont remember to slow down the same way as the plane will keep trying to do that speed until you land (hit the ground!).

The Tutorial flight is indeed your friend! Plus lots of practice.

Not at all what I was asking about. Sorry. Just curious as to how to get the error message away and learn how to keep it away

[wheels1911 1]

6 hours ago, JRBarrett said:

As the pilot, you can always use Speed INTV on the autopilot to change your descent speed.

The post above that you just sent had great information!! thank you!!

 

One more question for you. tonight when I was flying I tried to Press Speed INTV and I couldn't deselect N1 Speed............ the Entire Speed Hold section was greyed out and I have no idea how to manual override it once Vnav and Lnav are active.

[Stearmandriver 2,271]

5 hours ago, DaveCT2003 said:

EDIT: Something else occured to me.  Often time one hear's it said that "I'll enter that into the FMC", which is TECHINICALLY accurate.  It's done VIA the CDU, but it's entered into the FMC.  This may be a point of confusion.

 

This is my whole point; it's accurate to say you are entering or modifying this information in the FMC, because you are.  It's like, when I bug minimums, I'll say "I've set 615 in the BARO bug for minimums", because that's where I entered it. I used the EFIS Control Panel to do that, but no one would say "I've entered 615 on the EFIS Control Panel".

As for your opinions of civilian vs military aviators, well, I hate to broad brush anyone because that's never really accurate... But I will say that many of the biggest problem children at the airlines, both in training performance and in attitude when on line, don't come from civilian backgrounds ;-). 

 

[sloppysmusic 224]

6 hours ago, Stearmandriver said:

This is my whole point; it's accurate to say you are entering or modifying this information in the FMC, because you are.  It's like, when I bug minimums, I'll say "I've set 615 in the BARO bug for minimums", because that's where I entered it. I used the EFIS Control Panel to do that, but no one would say "I've entered 615 on the EFIS Control Panel".

 

 

I'm typing this into my computer right now..if you told me no I am actually typing this into my keyboard I'd say that wasn't right. To be pedantic I am actually typing this into my computer WITH my keyboard. Except no-one would ever say that without getting weird looks. I was right the first time either way as I AM typing this into my computer regardless of the interface.

If everyone know what you mean and you are not doing anything wrong or dangerous I don't think minor corrections are all that helpful. 

Edited November 17, 2018 by sloppysmusic

[Fabo 213]

 

 

On 11/16/2018 at 6:12 PM, FalconAF said:

SimBrief will do that depending on some different factors you input about the flight.  Like most times if I use a SWA flight designator (for Southwest Airlines) I get a really low Cost Index used for the flight plan.  It's not unusual to get a single-digit one that will make my descent speeds much lower than many, many STAR crossing speed restrictions.  You can see them in the FMC waypoints list when you verify your flight plan using the "Step" sequence after entering the flightplan in the FMC.  That is when you can initially make the adjustments recommended above in previous posts to make sure you have a descent profile that fits the crossing restrictions for STAR arrivals in the plan.

I think SimBrief has been designed to determine Cost Index values based on the airline designator used.  I might be wrong about that though.  In any case, Southwest flight plans consistently get lower Cost Index values when I use SimBrief, because in real life, Southwest does use lower Cost Index values.  That works for the climb and cruise portions of the flights, but the pilot(s) would still have to adjust the descent profiles to comply with STAR crossing restriction speeds if needed.

 

SimBrief makes the CI fit your planned flight time, with some assumptions made about taxi times. If you are using real flight times, then probably Southwest just plans longer than other airlines.

[FalconAF 213]

23 hours ago, Fabo said:

SimBrief makes the CI fit your planned flight time, with some assumptions made about taxi times. If you are using real flight times, then probably Southwest just plans longer than other airlines.

That would make sense too.  I know I read somewhere that SimBrief will "select" different cost indexes for different reasons, and I thought one of them was also based on a table of "common" real world CI's for individual airlines.   But from my understanding, SimBrief also uses real world FlightAware routes and flight times based on the selections you input for the flight plan (aircraft type, airline, etc).  So it very well may be looking at a proposed flight time from somewhere like FlightAware, and coupling that with the aircraft type for the flight plan it is creating to get a recommended CI.