Welcome Guest. Sign in or Signup

6 Answers

RAIM

Asked by: 3999 views General Aviation

Receiver Atonomous Integreity Monitoring. What is the purpose of RAIM??

Ace Any FAA Written Test!
Actual FAA Questions / Free Lifetime Updates
The best explanations in the business
Fast, efficient study.
Pass Your Checkride With Confidence!
FAA Practical Test prep that reflects actual checkrides.
Any checkride: Airplane, Helicopter, Glider, etc.
Written and maintained by actual pilot examiners and master CFIs.
The World's Most Trusted eLogbook
Be Organized, Current, Professional, and Safe.
Highly customizable - for student pilots through pros.
Free Transition Service for users of other eLogs.
Our sincere thanks to pilots such as yourself who support AskACFI while helping themselves by using the awesome PC, Mac, iPhone/iPad, and Android aviation apps of our sponsors.

6 Answers



  1. John D. Collins on Apr 04, 2013

    RAIM is an algorithm that is used to determine if the GPS position can be relied on for the navigational accuracy a particular mode of navigation requires. For enroute, +/- 4 NM is required, for terminal operations +/- 1 NM is required. For a non precision approach, +/- .3 NM is required. If the accuracy can’t be assured, the GPS receiver generates an alarm indicating to the pilot that they can’t depend on the GPS for navigation and must use alternative means of navigation.

    0 Votes Thumb up 0 Votes Thumb down 0 Votes



  2. alaskanfly3r on Apr 05, 2013

    What is that +/- nautical mile about? Is that how much you can be off-course?

    0 Votes Thumb up 0 Votes Thumb down 0 Votes



  3. ccwebb on Apr 08, 2013

    The +/-NM is showing what the full scale swing of the CDI is. Between centered and full deflection will be +(right) or -(to the left) that many miles.

    A pilot is required to maintain at least Instrument Pilot PTS minimums of 3/4 scale deflection. In other words, 3.5 dot deflection. (Of course, ATC may still get on to you for being less off course.)

    0 Votes Thumb up 0 Votes Thumb down 0 Votes



  4. alaskanfly3r on Apr 11, 2013

    so the 4 NM to the right, and 4 NM to the left? and 2 NM to the right and 2 NM to the left and so on??

    0 Votes Thumb up 0 Votes Thumb down 0 Votes



  5. ccwebb on Apr 12, 2013

    Yes. +/-5 NM means that a CDI on the last deviation dot (the 5th dot) you will be 5 NM off course. Each dot would represent 1 NM, on this scale. When the scale changes the value of each dot would change as well.

    0 Votes Thumb up 0 Votes Thumb down 0 Votes



  6. alaskanfly3r on Apr 12, 2013

    well i guess that covers it for me. thanks john and ccwebb for providing me with some answers. much appreciated. safe flying!

    0 Votes Thumb up 0 Votes Thumb down 0 Votes


The following terms have been auto-detected the question above and any answers or discussion provided. Click on a term to see its definition from the Dauntless Aviation JargonBuster Glossary.

Answer Question

Our sincere thanks to all who contribute constructively to this forum in answering flight training questions. If you are a flight instructor or represent a flight school / FBO offering flight instruction, you are welcome to include links to your site and related contact information as it pertains to offering local flight instruction in a specific geographic area. Additionally, direct links to FAA and related official government sources of information are welcome. However we thank you for your understanding that links to other sites or text that may be construed as explicit or implicit advertising of other business, sites, or goods/services are not permitted even if such links nominally are relevant to the question asked.