RVSM

1
RVSM

• AIRWORTHINESS

PRESENTED BY COSCAP-SA
2
RVSM Airworthiness

• In the late 1950s it was recognized that as a
  result of the reduction of accuracy of pressure
  sensing of barometric Altimeters with increasing
  altitude,there was a need above a certain flight
  level to increase the prescribed vertical
  separation minimum of 300 m. In 1960 an increased
  separation of 600 m was established.

3
RVSM Airworthiness

• In the mid 1970s following the world fuel
  shortages and the escalation of fuel costs,
  allied to the growing demand for a more efficient
  utilization of the available airspace, ICAO
  encouraged states to conduct a detailed appraisal
  of the proposal to reduce the VSM above FL290.

4
RVSM Airworthiness

• In late 1988 the ICAO panel provided guidance to
  a specialist group tasked with translating the
  total vertical error distribution requirement
  into detailed specifications and procedures for
  controlling the height keeping standards of
  aircraft operating in RVSM airspace.

5
RVSM Airworthiness

• The detailed specification and procedures must
  be developed for use by Designers, Manufacturers,
  Operators and Approval Authorities and must be
  applicable for airworthiness approval to a Group
  of Aircraft as well as Individual Aircraft.
• When taken together this formed the Minimum
  Aircraft System Performance Specification ( MASPS
  )

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RVSM Airworthiness

• The following characteristics were developed by
  the ICAO team to satisfy the distribution limit
  on T V E of the proportion of Height keeping
  errors
• beyond 90 m in magnitude is less than 2.0X10-3
• beyond 150 m in magnitude is less than 3.5X 10
  -6
• beyond 200m in magnitude is less than 1.6X10
  -7,and
• between 290 320 m in magnitude is less than 1.7
  X 10 -9

7
RVSM Airworthiness

• These were intended to be the basis for
  development of the Minimum Aircraft System
  Performance Specification against which the
  Aircraft will be Approved.

8
RVSM Airworthiness

• The Mean Altimetry System Error of the Group of
  Aircraft shall not exceed 25 m( 80 ft)
• The sum of the absolute value of the mean ASE for
  the group and three standard Dev. Of ASE within
  the group shall not exceed 75 m
• The errors in altitude keeping shall be
  symmetrical about a mean of 0 and shall have a
  standard dev. Not more than 13 m and be such that
  the Error Frequency decreases with increasing
  Error magnitude at a rate which is at least
  exponential.

9
RVSM Airworthiness

• These characteristics were mainly to derive Type
  Approval standards for design capability ,but
  they primarily address the central part of the T
  V E distribution i.e the requirement of height
  keeping errors beyond 90 m magnitude is less than
  2.0X 10 -3.
• In order to qualify the aircraft for other
  requirements it was felt necessary to develop
  detailed procedure and specification to cover
  production release and continued Airworthiness.

10
RVSM Airworthiness

• The Minimum Aircraft System Performance
  Specification ( MASPS ) was required to control
  three issues, Type Approval, Production Release,
  and Continued Airworthiness.
• Though it was necessary to meet all the
  requirements of MASPS for approval of operation
  in RVSM airspace it was also essential to change
  the structure of MASPS for existing
  aircraft,some of which may no longer be in
  production

11
RVSM Airworthiness

• On the basis of the ICAO studies, a
  recommendation was made that the margin between
  operational Performance and Design capability
  should be achieved as under
• The mean uncorrected Residual position Error
  (Static Source Error ) of the group shall not
  exceed 25 m
• The sum of the absolute value of the mean ASE
  within the group shall not exceed 60 m (This
  requirement has a narrower tolerance to allow for
  some degradation with increasing age)

12
RVSM Airworthiness

• Each individual aircraft in the group shall be
  built to have an ASE contained within 60 m
• An automatic altitude-keeping device shall be
  required and will be capable of controlling
  altitude within a tolerance band of 15m about
  commanded altitude when operated in the altitude
  hold mode in straight and level flight under
  non- turbulent, non-gust condition

13
RVSM Airworthiness

• Equipment and Functional requirements.
• Essential features for operation in RVSM
  airspace
• At least Two altitude measurement system
• Static source error correction /position error
  correction must be applied automatically

14
RVSM Airworthiness

• An SSR altitude reporting Transponder with the
  capability for switching to operate from either
  altitude measurement system.
• An altitude alert system that alerts the crew
  aurally and visually if displayed altitude
  deviates from the selected altitude by more than
  60 m

15
RVSM Airworthiness

• An automatic Altitude keeping device to control
  altitude within a tolerance band of 15 m and
  designed such that the occurrence of any single
  failure in the device will not cause a
  displacement of the aircraft from its flight
  path greater than 90 m based on a 3 second
  delay in pilot intervention

90 M
16
RVSM Airworthiness

• An out-of-trim condition which can not easily be
  controlled by the Pilot.
• Any action of the flight control system that is
  not readily apparent to the pilot by movement of
  the flight controls,a flight instrument display
  ,or by display of an advisory
• note 1 Aircraft operating as on 1/1/90 with
  altitude keeping capability of 40 m need not be
  retrofitted future aircraft req. 15 m
• note 2 After 1/1/94 all RVSM airspace operating
  aircraft should meet the performance requirement
  of less than 45 m altitude overshoot

17
RVSM Airworthiness

• Continued Airworthiness
• The Maintenance requirements and procedures
  should include periodic flight test demonstration
  of height-keeping accuracy.
• Independent TVE monitoring facility is acceptable
  provided errors can be measured consistent to the
  requirements and provided separate contributor to
  TVE I.e Airframe, Avionics or flight Technical
  Error can be assessed

18
RVSM Airworthiness

• IT is unlikely that many existing aircraft can be
  shown to have undergone the production release
  controls envisaged in the MASPS but Continued
  Airworthiness requirement should be developed so
  that the limits are met. Each such aircraft
  should undergo the appropriate check as well as
  meeting the type approval requirements.
• For young in-service aircraft there should be a
  requirement to reveal evidence of variation to
  normal production repeatability.

19
RVSM Airworthiness

• All Aircraft operating above FL 290 must be
  approved for such operation by the state of
  registry of the aircraft or of the aircraft
  operator. For Airworthiness,
• The Aircraft should be approved as meeting the
  requirements of the appropriate state
  airworthiness document derived from the height
  keeping capability requirements for operations in
  RVSM airspace.
• The aircraft altimetry and height keeping
  equipment must be maintained in accordance with
  approved procedures and servicing schedules
  END