Height keeping performance monitoring for RVSM approval - Edgevarsity Blog Edgevarsity
Height keeping performance monitoring for RVSM approval

Height keeping performance monitoring for RVSM approval

Imagine driving in bumper to bumper traffic. Oh! No need to imagine. Just drive your car and on most of the roads, you witness this. Your chance of surviving the traffic without hurting yourself or your car depends not only on your driving skills, but depends significantly on the skill level of the fellow driver and also significantly depends on the serviceability of vehicle sensors which would warn the driver if the vehicle intercept or come closer to other vehicles.

Imagine, you are in a 3 D plane driving your car and there is a big lorry carrying bulky cargo above you. How close would you consider the vertical distance as ‘sweet’ and further closer would be ‘scary’? 

If your height and the height of the lorry above you are monitored accurately, you can continue to maintain a safe and we can term it as “sweet distance”. As a responsible driver, I have to keep my vehicle serviceable especially those instruments that are associated with distance and height measurement serviceable all the time to avoid accidents. Added to this, there should be independent agencies that monitor the height at regular intervals to boost my confidence during increased traffic.

The reduced vertical separation is to cater to the increased air traffic. This is termed Minimum Aircraft System Performance Specifications and abbreviated as MASPS.

To achieve the MASPS, the aircraft should have some basic standard configuration, accurate altimetry system and adherence to continued airworthiness (CAW) procedures necessary to ensure that the performance is maintained.

Aircraft operators who demonstrate both technical compliance and the application of appropriate operational procedures are authorized to operate within the reduced vertical separation minima. This is abbreviated as RVSM.

Technical compliance, CAW, and operational procedures are all internal to the aircraft / organization and along with that, there are independent external agencies that would monitor the height keeping.

These agencies employ different ways to ensure the height keeping performance and which method to employ at what interval is the prerogative of the local regulatory agency.

GPS based monitoring system is one such method where special instruments are fitted in the aircraft on the day of inspection. These GPS instruments would collect the aircraft height data inflight. The interval or frequency of this type of height monitoring is specified by the respective national aviation agencies.

In the second method, aircraft have to overfly a ground based station. While the Aircraft overfly, height is monitored. There are very few stations across the globe that provide this facility. 

In the third method, height is monitoring through an Automatic Dependent Surveillance Broadcast (ADS-B). This is a means by which aircraft can automatically transmit and receive data such as identification, position, altitude and other parameters in a broadcast mode via a data link.

Online aircraft maintenance engineering programs are expected to teach RVSM principle and responsibility of CAMO engineers in maintaining required criteria as a part of their training program.


by Sumanth Eswar

Ex Assistant Manager-Technical Services, Jet Airways

14 years of industry experience in various sections under Engineering and Maintenance department such as Engineering Planning, Technical Services Engineering including Structures, Cabin Maintenance, Airframe and Systems, Base Maintenance, Powerplant, Reliability, Aircraft Weighing, Rotable Management. Years of Safety Office experience and was a surveyor for Aircraft Insurance