Singapore legislation
Schedule 2
of Air Navigation (98 — Special Operations) Regulations 2018
Schedule 2
Minimum Aircraft Systems Performance Specifications (MASPS)
SECOND SCHEDULERegulation 14(b)Minimum Aircraft Systems Performance Specifications (MASPS)Definitions
1. In this Schedule —“Altimetry system error” or “ASE” means the difference between the altitude indicated by the altimeter display (assuming the altimeter barometric setting is correct) and the pressure altitude corresponding to the undisturbed ambient pressure;“Total vertical error” or “TVE” means the vertical geometric difference between the actual pressure altitude flown by an aircraft and its assigned pressure altitude (flight level).Minimum Aircraft Systems Performance Specifications (MASPS)
2. In respect of a group of aeroplanes that are nominally of identical design and build with respect to all details that could influence the accuracy of an aeroplane’s height‑keeping performance capability, the performance of the altimeter system for operation by the group of aeroplanes in RVSM airspace is such that the total vertical error for the group of aeroplanes —
has a mean no greater than 25 m (80 ft) in magnitude; and
has a standard deviation (z) with a magnitude no greater than —
if the mean TVE is measured in metres, the value of 28 ‑ 0.013z2 for 0 ≤ z ≤ 25; or
if the mean TVE is measured in feet, the value of 92 ‑ 0.004z2 for 0 ≤ z ≤ 80.
3. The components of total vertical error mentioned in paragraph 2 must have the following characteristics:
the mean ASE of the group must not exceed 25 m (80 ft) in magnitude;
the sum of the absolute value of the mean ASE and 3 standard deviations of altimetry system error must not exceed 75 m (245 ft);
the differences between cleared flight level and the indicated pressure altitude actually flown must be symmetric about a mean of 0 m (0 ft), with a standard deviation no greater than 13.3 m (43.7 ft);
the frequency of the differences occurring must decrease exponentially with the increase in the magnitude of the differences.
4. In respect of any aeroplane that cannot be classified as belonging to a group of aeroplanes as the characteristics of the aeroplane’s airframe and altimetry system fit are unique, the height‑keeping performance capability of the aeroplane must be such that the components of the total vertical error for the aeroplane have the following characteristics:
the magnitude of the aeroplane’s altimetry system error must not exceed 60 m (200 ft) under any flight condition;
the difference between the cleared flight level and the indicated pressure altitude actually flown must be symmetric about a mean of 0 m (0 ft), with a standard deviation no greater than 13.3 m (43.7 ft);
the frequency of the differences occurring must decrease exponentially with the increase in the magnitude of the differences.