China Reduced Vertical Separation Minima (RVSM)
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|Category:||Loss of Separation|
In November 2007, China implemented Reduced Vertical Separation Minima (RVSM), between 8,900m (FL291)and 12,500m (FL411) inclusive, in the Shenyang, Beijing, Shanghai, Guangzhou, Kunming, Wuhan, Lanzhou and Urumqi FIRs and Sector AR01 (island airspace) of the Sanya CTA. The China RVSM airspace is exclusive RVSM airspace and aircraft that are not RVSM compliant may not operate within it unless specific waivers (for example, State aircraft) have been granted.
A Flight Level Allocation Scheme (FLAS) is the foundation for the Reduced Vertical Separation Minimum (RVSM) program. In most areas of the world, implementing States have used a consistent FLAS based upon flight levels expressed in the unit of feet. However, China, in developing its FLAS, has taken a different approach.
China Flight Level Allocation Scheme (FLAS)
The China FLAS was designed to satisfy their military requirements of applying metric flight levels while at the same time mitigating the relatively big altitude difference between RVSM metric flight level and feet flight levels of neighbouring countries. It also eliminates the phenomena of 900 feet vertical separation associated with metric RVSM flight levels and makes the vertical separation between aircraft 1000 feet or more. To accomplish this, clearances are provided in metres, converted using a specific China RVSM table and flown in feet.
To ensure compliance, the operator shall ensure that the pilot has been trained on China RVSM Flight Level Allocation Scheme (FLAS) before operating in China airspace. Procedures for the RVSM airspace include (but are not limited to):
- Equipment - Altimeters must allow the aircraft to be flown in feet. Aircraft must be equipped with:
- two primary altimetry systems
- one automatic altitude-keeping device; and
- one altitude-alerting device.
- Clearance - Altitude clearances will be provided in metres
- Conversion - Pilots will convert the cleared altitude in metres to feet using ONLY an approved China RVSM Conversion Table. As some rounding of values has been incorporated into the table, using any other means to convert values can lead to compromised vertical separation between aircraft.
- Execution - The value in feet, as extracted from the conversion table, is the flight level to be flown. Note that aircraft with both feet and metric altimeters MUST NOT fly the cleared level in metres. The conversion MUST be made and the aircraft flown referencing feet.
China RVSM Conversion Table
A typical China RVSM Conversion Table is as depicted in the illustration. In this example, the dark blue lines are for eastbound traffic and the light blue for westbound.
As an operational example, a westbound aircraft might be cleared by ATC to climb to and maintain (FL) 11600 metres. Referring to the table, 11600 metres converts to 38100 feet.
The pilot would set FL381 in the aircraft altitude select panel and climb as cleared.
Upon reaching FL381, if required for the region of flight, the pilot would report level at 11600 metres.
In the same manor, an eastbound aircraft might be cleared to descend to (FL) 9800 metres. Using the Conversion Table, the pilot would extract FL321, set that flight level in the aircraft altitude select panel and descend calling level at the cleared metric flight level if required.
Entering or Leaving Chinese FIRs
The transition to China RVSM levels will normally happen outside Chinese airspace in the adjacent FIR. When flight planning, pilots or dispatchers should identify the transition area on their proposed route of flight and file the appropriate level change. Note that a clearance to change from ICAO RVSM levels to China RVSM or from China RVSM to ICAO RVSM levels must be received and acknowledged before any level change is executed.