China’s Plan to Introduce Reduced Vertical
Separation Minimums Radius on its Airspace

Only one year before the 2008 Olympic Games Inauguration Ceremonies, Chinese aviation authorities are planning to introduce the Reduced Vertical Separation Minimums’ system on a nationwide basis to cope with the expected air-traffic congestion associated with the games. In the past, Chinese officials have requested technical assistance from Europe and the United States in order to handle the implementation of new systems for China’s aging ATC system. The US Federal Aviation Agency has been providing technical advisors to China on this matter since July 2005. Chinese officials see the incorporation of RVSM as an integral part of the modernization of China’s civil aviation sector. China already uses the RVSM system on one of its ocean going flight pattern region and has plans to add up nine more regions to the system, all in the mainland. Even with this first step, China lags far behind other nations. A global transition to RVSM has been underway since the heavily used North Atlantic Airspace Region switched from 2,000ft to 1,000ft altitudes intervals in the fall of 1997. Australia was the first major commercial market to implement RVSM in 2001, Europe followed a year later, and United States incorporated the system in 2005.

However, one aspect of the proposed Chinese RVSM system that must be considered by the commercial aviation industry is the fact that China is the first nation to implement a RVSM system in meters, instead of the traditional feet scale. This could trigger errors in flight operations due to the different altitude measurements. The Chinese air control system would assign a pilot an RVSM altitude in meters, then the pilot, using a Chinese supply conversion table; will translate this figure into a feet scale. Today, many Boeing and Airbus commercial carriers posses altimeters that can be set on meters, but this feature will not apply to China-bound flight routes. Here then lies the potential problem with China’s RVSM system. If an aircraft is assigned by RVSM an altitude of 9,800 meters, which equals 32,150ft, using the RVSM conversion table, the pilot would round this figure to the closest 100ft mark and then set the airplane on a 32,100ft altitude. Back on the ground, the air traffic controller will see the metric conversion, and the ATC display will show the plane’s current altitude at 9,780 meters, not the assigned altitude of 9,800 meters. This would lead to confusion regarding the planned altitude patterns of all flights. Added to this potential problem is that most of China’s neighbors still use several types of altitude cruising level systems, including the conventional 2,000ft separation. This will require the pilot to adjust the plane’s altitude as its travel from a national air-space to another.

Ideally, China will implement a RVSM system based on a feet scale, as most of the world already does, but the Chinese Air Force have all their air equipment pre-programmed in meters and a conversion to a feet scale would probably disrupt the current military state of their Air Force. Thus China would go on to use the meter scale for the foreseeable future. Eventually, the world community should design and implement an RVSM system of uniformity for all nations to use, but this is a long term vision today; China needs to make the necessary arrangements, perform the necessary experimentation and trials with its RVSM system in order to minimize confusion or even incidents when the entire country converts to RVSM.

– Raul Colon


More information:
FAA Website: Reduced Vertical Separation Minimum
Pilot Journal: What’s RVSM?

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