Cloud surfer,
this is JAR OPS requirements for the class a airplanes:
AMC OPS 1.495(d)(1) & (e)(1)
Required Navigational Accuracy
See JAR-OPS 1.495(d)(1) & (e)(1)
1 Flight-deck systems. The obstacle accountability semi-widths of 300 m (see JAR-OPS 1.495(d)(1))
and 600 m (see JAR-OPS 1.495(e)(1)) may be used if the navigation system under one-engine-inoperative
conditions provides a two standard deviation (2 s) accuracy of 150 m and 300 m respectively.
2 Visual Course Guidance
2.1 The obstacle accountability semi-widths of 300 m (see JAR-OPS 1.495(d)(1)) and 600 m (see JAROPS
1.495(e)(1)) may be used where navigational accuracy is ensured at all relevant points on the flight
path by use of external references. These references may be considered visible from the flight deck if they
are situated more than 45° either side of the intended track and with a depression of not greater than 20°
from the horizontal.
2.2 For visual course guidance navigation, an operator should ensure that the weather conditions
prevailing at the time of operation, including ceiling and visibility, are such that the obstacle and/or ground
reference points can be seen and identified. The Operations Manual should specify, for the aerodrome(s)
concerned, the minimum weather conditions which enable the flight crew to continuously determine and
maintain the correct flight path with respect to ground reference points, so as to provide a safe clearance
with respect to obstructions and terrain as follows:
a. The procedure should be well defined with respect to ground reference points so that the track to
be flown can be analysed for obstacle clearance requirements;
b. The procedure should be within the capabilities of the aeroplane with respect to forward speed,
bank angle and wind effects;
c. A written and/or pictorial description of the procedure should be provided for crew use;
d. The limiting environmental conditions (such as wind, the lowest cloud base, ceiling, visibility,
day/night, ambient lighting, obstruction lighting) should be specified.
[Ch. 1, 01.03.98]
IEM OPS 1.495(f)
Engine failure procedures
See JAR-OPS 1.495(f)
If compliance with JAR-OPS 1.495(f) is based on an engine failure route that differs from the all engine
departure route or SID normal departure, a “deviation point” can be identified where the engine failure route
deviates from the normal departure route. Adequate obstacle clearance along the normal departure with
failure of the critical engine at the deviation point will normally be available. However, in certain situations
the obstacle clearance along the normal departure route may be marginal and should be checked to ensure
that, in case of an engine failure after the deviation point, a flight can safely proceed along the normal
departure.
For performance calculations regarding class B airplanes:
IEM OPS 1.535
Obstacle Clearance in Limited Visibility
See JAR-OPS 1.535
1 The intent of the complementary requirements JAR-OPS 1.535 and Appendix 1 to JAR-OPS
1.430 sub-paragraph (a)(3)(ii) is to enhance safe operation with Performance Class B aeroplanes in
conditions of limited visibility. Unlike the Performance Class A Airworthiness requirements, those for
Performance Class B do not necessarily provide for engine failure in all phases of flight. It is accepted
that performance accountability for engine failure need not be considered until a height of 300 ft is
reached.
2 The weather minima given in Appendix 1 to JAR-OPS 1.430 sub-paragraph (a)(3)(ii) up to and
including 300 ft imply that if a take-off is undertaken with minima below 300 ft a one engine inoperative
flight path must be plotted starting on the all-engine take-off flight path at the assumed engine failure
height. This path must meet the vertical and lateral obstacle clearance specified in JAR-OPS 1.535.
Should engine failure occur below this height, the associated visibility is taken as being the minimum
which would enable the pilot to make, if necessary, a forced landing broadly in the direction of the
take-off. At or below 300 ft, a circle and land procedure is extremely inadvisable. Appendix 1 to JAROPS
1.430 sub-paragraph (a)(3)(ii) specifies that, if the assumed engine failure height is more than
300 ft, the visibility must be at least 1500 m and, to allow for manoeuvring, the same minimum visibility
should apply whenever the obstacle clearance criteria for a continued take-off cannot be met.
AMC OPS 1.535(a)
Take-off Flight Path Construction
See JAR-OPS 1.535(a)
1 Introduction. For demonstrating that an aeroplane clears all obstacles vertically, a flight path
should be constructed consisting of an all-engine segment to the assumed engine failure height,
followed by an engine-out segment. Where the Aeroplane Flight Manual does not contain the
appropriate data, the approximation given in paragraph 2 below may be used for the all-engine
segment for an assumed engine failure height of 200 ft, 300 ft, or higher.
2 Flight Path Construction
2.1 All-Engines Segment (50 ft to 300 ft). The average all-engines gradient for the all-engines
flight path segment starting at an altitude of 50 ft at the end of the take-off distance ending at or
passing through the 300 ft point is given by the following formula:
Y300 =0•57(YERC)/1 + (VERC*2 – V2*2) / 5647
NOTE: The factor of 0.77 as required by JAR-OPS 1.535(a)(4) is already included where:
Y300 = Average all-engines gradient from 50 ft to 300 ft
YERC = Scheduled all engines en-route gross climb gradient
VERC = En-route climb speed, all engines knots TAS
V2 = Take-off speed at 50 ft, knots TAS
(See IEM OPS 1.535(a), Figure 1a for graphical presentation)
2.2 All-Engines Segment (50 ft to 200 ft). (May be used as an alternative to 2.1 where weather
minima permits) The average all-engine gradient for the all-engine flight path segment starting at an
altitude of 50 ft at the end of the take-off distance ending at or passing through the 200 ft point is given
by the following formula:
Y200=0 51(Yerc )/1 (Verc*2 – V2*2 ) / 3388
NOTE: The factor of 0.77 as required by JAR-OPS 1.535(a)(4) is already included where:
Y200 = Average all-engines gradient from 50 ft to 200 ft
YERC = Scheduled all engines en-route gross climb gradient
VERC = En-route climb speed, all engines, knots TAS
V2 = Take-off speed at 50 ft, knots TAS
(See IEM OPS 1.535(a), Figure 1b for graphical presentation)
Hope it could help. Sorry got a bit too long.
Cheers.
