FAA Instrument Rating Airplane (IRA)IFR Procedures and ChartsEasy
A pilot is flying an IFR flight at 7,000 feet MSL. The en route low-altitude chart for the segment being flown shows an MEA of 6,000 feet MSL and a MOCA of 5,000 feet MSL. Which altitude range ensures both obstacle clearance and navigation signal reception for the entire segment?
- ABetween 5,000 feet MSL and 6,000 feet MSL.
- BAt or above 7,000 feet MSL.
- CAt or above 5,000 feet MSL.
- DAt or above 6,000 feet MSL.
Show answer & explanationAnswer & explanation
Correct answer: D. At or above 6,000 feet MSL.
The Minimum En Route Altitude (MEA) guarantees both obstacle clearance and navigation signal reception along the entire airway segment. The MOCA only guarantees obstacle clearance and navigation signal reception within 22 nautical miles of the nearest VOR.
Why the other options are wrong
- A. Flying between MOCA and MEA does not guarantee full navigation signal reception for the entire segment.
- B. 7,000 feet MSL is a valid altitude for IFR flight, but the question asks for the minimum altitude that ensures both, which is the MEA.
- C. 5,000 feet MSL is the MOCA, which only guarantees navigation within 22 NM of a VOR, not the entire segment.
MEA vs. MOCA (En Route)
The Minimum En Route Altitude (MEA) guarantees both obstacle clearance and navigation signal reception for the entire segment of an airway. The Minimum Obstruction Clearance Altitude (MOCA) only guarantees obstacle clearance and navigation signal reception within 22 nautical miles of the VOR defining the airway.
- MEA: Obstacle clearance + navigation signal for entire segment.
- MOCA: Obstacle clearance + navigation signal within 22 NM of VOR.
- MEA is typically higher than or equal to MOCA.
- Pilots must adhere to MEA for full route navigation/clearance.
Memory trick: MEA: My Entire Airway, MOCA: My Only Close Area!