Welcome Guest. Sign in or Signup

2 Answers

What is best Rate of descent and how is it different from minimum rate of descent ?

Asked by: 11916 views Aerodynamics

how are minimum Rate of Descent and best rate of descent different ?

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.

2 Answers



  1. Brian on Mar 06, 2011

    Might you be referring to best glide versus minimum sink airspeeds?
     
    Best glide airspeed – The speed that provides the greatest gliding distance (assuming no winds). This speed is published, but only for gross weight. To correct for weight we can take the square root of (actual weight / gross weight) and multiply it by the published best glide speed.
     
    Best glide speed corresponds to the angle of attack that yields minimum drag. It is because best glide is based on an angle of attack that best glide speed varies with weight. A similar relationship can be seen with stall speed. In fact, the above formula will work where published best glide speed is replaced with publish stall speed.
     
     
    Minimum sink – The speed that yields the greatest time aloft, or minimum rate of descent. Typically, this speed is not published. However, in small aircraft, it will occur about 5 knots below the published best glide speed corrected for current aircraft weight.
     
    Minimum sink corresponds to the speed of minimum power required.

    +3 Votes Thumb up 4 Votes Thumb down 1 Votes



  2. Heather McNevin on Mar 10, 2011

    I’m not sure but I’m thinking maybe you’ve heard a controller say “give me your best rate of descent”.  Pilots and controllers may have different views on descending, that might be where your question lies.  As a pilot, I descend at a rate that is confortable for me and my passengers, one that is acceptable for the aircraft limitations, and one that I plan that puts me at my desired altitude when I want to be there.  Many times, this is a nice gentle descent.  Of course, if I have an engine failure, I’m aiming for best glide and a minimum descent angle – I want to stay airborne as long as possible.  Controllers are often looking at traffic, and may want you to get out of the way quickly.  If a controller says, best rate; its not you’re best glide, its your maiximum descent rate.  Descend and get out of the way is what theyre saying!

    +2 Votes Thumb up 2 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.