Asked by: Juventino Dickenstein
business and finance aviation industry

What is the purpose of an off Route obstruction clearance altitude along a designated route?

Last Updated: 13th May, 2020

An off-route obstruction clearance altitude (OROCA) is an off-route altitude that provides obstruction clearance with a 1,000-foot buffer in non- mountainous terrain areas and a 2,000-foot buffer in designated mountainous areas within the United States.

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Furthermore, what is VFR on top clearance?

“A VFR-on-top clearance allows a pilot to climb through a cloud layer or some other condition of less than basic Visual Meteorological Conditions (VMC). Additionally, the ATC clearance may contain alternate instructions if VFR-on-top is not reached by a specified altitude.

Similarly, how is minimum safe altitude calculated? MSA is minimum safety altitude and is required to be calculated and noted on your plog. It is the height of ground, rounded up to the next 100ft + 300ft for unmarked objects + 1,000ft safety.

Beside this, what is at Route in aviation?

RNAV terminal transition routes, referred to as Tango or “T” routes, allow Global Positioning System (GPS) equipped, instrument flight rules (IFR) operations to efficiently fly around or through Class B and Class C airspace areas.

What is emergency safe altitude?

Definition. An altitude which provides at least 1000 feet of obstacle clearance in nonmountainous areas or 2000 feet of obstacle clearance in designated mountainous areas within a 100 nautical mile radius of the navigation facility upon which the procedure is predicated.

Related Question Answers

Imobach Kasmirowsk


Can a VFR pilot fly VFR on top?

“The short answer is yes. You may legally fly on top as long as you can maintain the appropriate VFR cloud clearances. VFR-on-top is conducted by an instrument-rated pilot on an IFR flight plan. It allows the pilot to change altitudes, provided VFR cloud clearances are maintained.

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How high can a VFR pilot fly?

VFR cruising altitude rules in the US and Canada
Unofficially, most pilots use these rules at all levels of cruise flight. FAR 91.159 states that any aircraft: On a magnetic course of 0-179 degrees shall fly at an odd thousand ft MSL altitude +500 feet (e.g., 3,500, 5,500, or 7,500 ft); or.

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Can you fly above clouds VFR?

Since the regs list a minimum distance above clouds obviously VFR flights are allowed to fly over clouds. However, it's not clear what kind of clouds one can fly over: only individual smaller clouds, a broken layer or a solid layer.

Toshko Valerius


What are VFR minimums?

Basic VFR Weather Minimums
cloud ceiling at least 1,000 feet AGL; and. ground visibility at least 3 statute miles (usually measured by ATC but, if not available, flight visibility at least 3 statute miles as estimated by the pilot).

Aaya Jackobi


Can I fly VFR in MVFR?

Marginal VFR (MVFR): Ceilings 1,000 to 3,000 feet and/or visibility is 3-5 miles inclusive. This is when VFR pilots kill themselves all the time. You also need to maintain VFR cloud clearance in Class E airspace which starts at 700 or 1200 feet AGL. So if the cloud bases are at 2000 feet you have to fly at 1500 feet.

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How do I get a VFR over the top?

To fly VFR on top, you must be an instrument-rated pilot on an instrument flight plan and request a VFR-on-top clearance. (To complicate matters, this is sometimes called IFR over the top.) This allows you to climb through clouds to VFR weather above them.

Xerman Osterloh


What is a Q route?

Q routes are en route airway routes, between FL180 and FL450, which can be flown by RNAV equipped aircraft capable of conforming to navigation specified by RNAV 2. Q routes, in use since late 2003, provide more direct routing compared to conventional routes, and are intended to reduce flight distance and travel time.

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What is an unpublished RNAV route?

Unpublished RNAV routes are direct routes, based on area navigation capability, between waypoints defined in terms of latitude/longitude coordinates, degree-distance fixes, or offsets from established routes/airways at a specified distance and direction.

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What is rnav2?

For the purposes of this AC, the specified RNAV accuracy must be met 95% of the flight time. (1) RNAV 1 requires a total system error of not more than 1 NM for 95% of the total flight time. (2) RNAV 2 requires a total system error of not more than 2 NM for 95% of the total flight time.

Jalal Resino


What are y routes?

Y Routes are offshore RNAV routes. Aircraft flying the Y-routes must be equipped with GNSS and meet RNAV 2 performance requirements. Transition to an RNAV-based route structure reduces the dependency on ground-based navigational systems, improving the operational efficiencies of the National Airspace System.

Branko Villafaina


How wide is a victor airway?

When VORs are less than 102 nautical miles (NM) (189 km) from each other, the airway extends 4 NM (7.4 km) on either side of the centerline (8 NM (14.8 km) total width).

Decebal Schulzki



The MSA provides 1000 feet of obstruction clearance within the circle within 25NM of the fix. This is an MSL altitude hence the "altitude" in the Minimum Safe Altitude. If it was agl I would suspect they would say "height".

Laurens Eisvogel


Soledat Albarez


What is minimum vectoring altitude?

Minimum Vectoring Altitude (MVA) is the lowest altitude, expressed in feet AMSL (Above Mean Sea Level (MSL)), to which a radar controller may issue aircraft altitude clearances during vectoring/direct routing except if otherwise authorized for radar approaches, departures and missed approaches.

Yuval Muhlnikel


What is MCA in aviation?

In aviation, a minimum crossing altitude (MCA) is the lowest altitude at which a navigational fix can be crossed when entering or continuing along an airway that will allow an aircraft to clear all obstacles while carrying out a normal climb to the required minimum en route IFR altitude (MEA) of the airway in question

Liwen Freixo


What is minimum IFR altitude?

minimum IFR altitude (MIA) The lowest IFR (instrument flight rules) altitude established for use in a specific airspace. The minimum IFR altitude provides obstacle clearance but may or may not be within controlled airspace. Minimum altitudes are published on aeronautical charts.

Mike Vandenberg


What is the highest altitude a plane can fly?

The highest certified altitude of an airliner was Concorde's 60,000 feet. Today some of the corporate jets can fly at 51,000 feet. Q: What is the highest cruising altitude allowed? A: Most airliners are limited to 45,000 feet or less.

Hadji Cardona


What must a pilot do before entering Class D airspace?

Entry Requirements: To enter Class D airspace, a pilot must contact the control tower and establish two-way radio communication prior to entering the airspace. During the call, you must provide Air Traffic Control (ATC) with your position, altitude, current transponder code, and your destination/intentions.