Autopilot question?

[dueguard1]

Can someone clarify what is a DES sub mode, and why would a company prohibit these type of approaches??

 

[BoilerUP]

DES mode on the CRJ is similar to "Level Change". Basically you set a speed at which you want to descend, pull the thrust levers back, and the airplane will (try to) maintain that speed. Power controls the rate of descent.

Shooting a non-precision approach like that might keep you on speed, but it won't do sh!t for getting you to MDA or having you fly a stabilized approach.

Why do you keep asking all these CRJ system questions???

 

[rickair7777]

The problem with DES on aproaches is that in order to maintain airspeed at the set value, the AP will use pitch...possibly LOTS of it, depending on configuration. You don't want to arrive at MDA with the nose 14 degrees down and 3300 fpm down on the VSI!

DES is normally used only on a long descent out of the FL's when you are assigned a speed to maintain.

Sounds like he's got a copy of the limitations and is studying for an interview or new-hire class.

 

[Oakum_Boy]

Congratulations on the CRJ FMS and Autopilot Graduation Certificate. It opens so many doors.

 

[Edge540]

Can someone clarify what is a DES sub mode, and why would a company prohibit these type of approaches??

It is not the company that prevents this, it is was part of the CRJ 200 certification limitations. Just remember, don't use speed mode on non precisions.... VS is the "Best" way to do it....

Now, after having a lengthy conversation with a CRJ test pilot... I was told that that is a crock of poo and that pilots all over the world ignore this limitation, I am not one of them... But, supposedly the 700 and 900 do not have this limitation. I can't verify that, but someone else probably can.

 

[dueguard1]

Easy guys just hear to gather as much info as I can before ground school....yea I know the'll probabbly give me everything I need to know once I get there but just want to be as sharp as possible....thanks Again Guys!

 

[DoinTime]

The CRJ has three airspeed modes. IAS (indicated airspeed) CLB (climb) and DES (descent). The modes are accesed by cycling the "speed" button on the autopilot control panel.

The IAS mode will ignore climb or descent information and pitch the aircraft to maintain the chosen speed. CLB mode will pitch the aircraft to maintain the chosen speed unless it results in a descent. DES mode will pitch the aircraft to maintain chosen speed unless it results in a climb.

why would a company prohibit these type of approaches??

All of the speed modes are not positive engagements of an altitude change. They are contingent upon proper manipulation of the thrust levers. Vertical Speed is a much more stable and predictable means of shooting an approach, especially for people without much experience in general let alone in the CRJ.

 

[DoinTime]

Easy guys just hear to gather as much info as I can before ground school....yea I know the'll probabbly give me everything I need to know once I get there but just want to be as sharp as possible....thanks Again Guys!

Props to you on trying to get prepared for class. Depending on where you are going to be doing your new hire training Flight Info might be the best place to get correct information.

 

[TinGoose1]

..................

 

[Edge540]

Easy guys just hear to gather as much info as I can before ground school....yea I know the'll probabbly give me everything I need to know once I get there but just want to be as sharp as possible....thanks Again Guys!

Keep the questions coming, I can feel the neurons and synapses reconnecting when I read these questions... Helps keep me sharp.

 

[papanovember]

Careful on doing your own "research"

The only guy who failed out of my class did a lot of his own studying. The airline will teach you what they want you to know. And that is all you need to know.

 

[Hobit]

The questions are good. Keeps the info at the top of my thimble sized mind.

 

[Airboss]

If i remember systems class, i believe CLB results in no less than 50 FPM climb and DSC results in no less than 50 FPM descent rate.

 

[CaptainChris77]

A "stablized approach" is 1,000 FPM or less inside the FAF. Use of the DES mode does not guarantee 1,000 FPM or less... you could in fact be diving at the ground at 3,000 FPM.

 

[172driver]

A "stablized approach" is 1,000 FPM or less inside the FAF

That all depends who you fly for. SOP's are different everywhere.

 

[Stifler's Mom]

Easy guys just hear to gather as much info as I can before ground school....yea I know the'll probabbly give me everything I need to know once I get there but just want to be as sharp as possible....thanks Again Guys!

Do yourself a HUUUUUGEEEEEE favor though. When you have a question in ground school, don't tell the instructor, "The guys on flightinfo told me....."