MAJ Bud Carlson: USAF advanced instrument school

Flying Safety, Dec, 2004

Some pilots still hold to the idea that the "Big Sky" theory will keep them out of harm's way. They probably haven't flown within the last 10 to 20 years. With the number of general aviation, commercial and military flights continuing to increase as our economy grows, the Federal Aviation Administration (FAA) recognized that changes were needed to deal with the air traffic congestion. Air Traffic Control (ATC) and the FAA decided to make some changes to allow more airplanes into the same airspace and still keep everyone safe.

One of those changes is the implementation of Domestic Reduced Vertical Separation Minimums (DRVSM), which starts at 0901Z, 20 Jan 2005. DRVSM is the application of reduced vertical separation minimums (RVSM) in U.S. airspace. RVSM is new to the United States, but implementation began on a limited basis in the North Atlantic Region in 1997 and is now implemented in the majority of Europe, the Pacific, the Middle East, and Australia.

As has been demonstrated in these regions, domestic RVSM is projected to accrue the following benefits:

Operators

* Fuel Savings Benefits 2005-2016:

* $5.3 billion

* 6/1 benefit / cost ratio

* $393 million first-year savings--with 2.0 percent annual increase

* Greater availability of more fuel-efficient altitudes

* Greater availability of most fuel-efficient routes

* Increased probability that an aircraft will be cleared onto the desired route or altitude

Air Traffic National Airspace System (NAS) Operations

* ATC Flexibility (e.g., routing aircraft around storm systems)

* Mitigates conflict points

* Enhances volume of aircraft that can be accommodated in a given sector (sector throughput)

* Enables crossing traffic flows to be accommodated

* Reduces controller workload (e.g., reduced vectoring and FL changes)

* Provides for growth in NAS en route airspace capacity

The new areas where RVSM will be applied include the lower 48 states, Alaska, Atlantic and Gulf of Mexico High Offshore Airspace (including Houston and Miami Oceanic), San Juan FIR, southern Canada, and Mexico.

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What is RVSM? The short answer is that at flight levels (FL) 290 through 410, you will have only 1000 feet of vertical separation from other traffic instead of the standard 2000 feet. This opens up six new altitudes that ATC can assign. But, what is the catch? Will it still be possible to maintain the same level of safety?

In order to operate in airspace where RVSM is being applied, both you and your aircraft must be certified to operate under the RVSM rules. For the pilot, certification is a training issue. For an aircraft to be certified, it must meet the standards defined in Appendix G to FAR Part 91. Some of the most significant requirements include two independent altimeter systems, an autopilot that can maintain altitude [+ or -]65 feet, and an altitude alert system to warn you if aircraft altitude deviates more than 200 feet.

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What if your aircraft is not RVSM compliant? Can you still get cleared to a higher altitude? The short answer is "maybe." FAR 91 Appendix G states, "RVSM airspace is special qualification airspace; the operator and the aircraft used by the operator must be approved by the Administrator." The Memorandum of Understanding between the FAA and the DOD states, "The FAA will accommodate non-RVSM compliant military aircraft operation within DRVSM airspace, without mission degradation, to the extent practicable based upon existing traffic and safety considerations." That sounds great ... but, the FAA ran some computer simulations using RVSM rules and found that approximately 83 percent of operational errors occurred due to non-RVSM aircraft operating in RVSM airspace. Subsequent simulations lowered this error rate, but with the stipulation of no more than one non-RVSM aircraft per sector operating. Aircrews should remember that accommodation is based on controller workload, existing traffic and safety considerations. Other factors, such as weather or traffic saturation, may impact the controller's decision to grant access to RVSM airspace. If safety is the main goal, what do you anticipate ATC will say when you ask to climb above FL 290? The bottom line is you need to plan your flight at altitudes below RVSM airspace if you are non-RVSM compliant.

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If you must fly in RVSM airspace (and your aircraft is non-compliant) to accomplish your mission, you have three options:

--File an Altitude Reservation (ALTRV).

* Requires long lead times and little to no flexibility.

* Provides guaranteed altitudes.

--Call ARTCC and coordinate flight times and altitudes. (You will need to coordinate 60-240 minutes prior to filing your flight plan.)

* Try to incorporate a LOA with local ARTCCs for routine flights.

* Provides a better chance of getting accommodated.

--No Call--no advance coordination.

* File and Fly--Taking chance of getting accommodated.

* Have enough fuel to fly below RVSM or prepare to divert.