Welcome Guest. Sign in or Signup

3 Answers

Use of MOCA during IFR Flight

Asked by: 7672 views Airspace, General Aviation, Instrument Rating

Hi everyone, I have a question about using the MOCA during IFR flight-According to 91.177 the MOCA may be used provided the applicable navigation signals are available (meaning within 22 nm of a VOR if using a VOR for navigation). If I'm using a GPS for navigation (and filed myself as a "/G" with FSS) could I use the MOCA even if I'm more than 22nm from a VOR (assuming ATC allows me to have it of course). Thanks! Matt

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.

3 Answers



  1. Lucas on Jun 20, 2013

    Short answer: Yes.

    Long answer: safety should always come first in aviation. Accidents happen and changes are made. When you can’t see the ground, would you be comfortable being close to it?
    MOCA means Minimum Obstruction Clearance Altitude. If your GPS fails you might find yourself in a very uncomfortable position.

    Lucas
    http://www.pilottrainingsolutions.com

    0 Votes Thumb up 0 Votes Thumb down 0 Votes



  2. Wes Beard on Jun 20, 2013

    I don’t know if you can fly at the MOCA altitude while using GPS as the primary navaid or not. It is an interesting question.

    There are new MEAs just for GPS equipped aircraft. These are typically lower altitudes than the current MEAs based on VOR airways.

    From KARLO to PRC on V105 has one of these GPS MEAs.
    http://skyvector.com/?ll=34.42219548680464,-112.50557922435375&chart=408&zoom=1

    +1 Votes Thumb up 1 Votes Thumb down 0 Votes



  3. Mark Kolber on Jun 26, 2013

    I don’t see any regulatory reason why not. Most of the procedural texts describe the 22 NM VOR limitation but, according to the reg, the only requirement is the availability of a reliable navigational signal. The 22 NM limittaion only applies when VOR navigation is being used. Here’s what the applicable reg says (with my emphasis):

    ==============================

    91.177(a) Operation of aircraft at minimum altitudes. Except when necessary for takeoff or landing, or unless otherwise authorized by the FAA, no person may operate an aircraft under IFR below–

    (1) The applicable minimum altitudes prescribed in parts 95 and 97 of this chapter. However, if both a MEA and a MOCA are prescribed for a particular route or route segment, a person may operate an aircraft below the MEA down to, but not below, the MOCA, provided the applicable navigation signals are available. For aircraft using VOR for navigation, this applies only when the aircraft is within 22 nautical miles of that VOR (based on the reasonable estimate by the pilot operating the aircraft of that distance); or

    +4 Votes Thumb up 4 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.