Document ID: chunk:federal_register_of_legislation:F2005B01529:body:0:p1
Version: federal_register_of_legislation:F2005B01529
Segment Type: other
Provision Reference: 
Character Range: 0–2744

INSTRUMENT NUMBER:  CASA   32/97

CIVIL AVIATION ACT 1988

CIVIL AVIATION REGULATIONS

DETERMINATION
UNDER PARAGRAPH 178 (1) (b) OF THE
CIVIL AVIATION REGULATIONS

I, TERRY CHARLES ARTHUR WILSON, General Manager Flying Operations Branch, a delegate of the Civil Aviation Safety Authority, under paragraph 178 (1) (b) of the Civil Aviation Regulations:
 (a) revoke instrument number SRS 2/1992; and
 (b) determine that the method of calculating the lowest safe altitude for a route segment for which a lowest safe altitude has not been determined is the method set out in the Schedule.

[Signed T. Wilson]

Terry Wilson
General Manager
Flying Operations Branch

12 February 1997
__________________

SCHEDULE

Interpretation
1. In this Determination, unless the contrary intention appears:
"corrected highest terrain", in relation to the effective area of a route segment, has the meaning given in section 4;
"effective area", in relation to a route segment, has the meaning given in section 3;
"Grid LSALT" means the LSALT shown for a grid square on an En Route Chart (ERC) or Terminal Area Chart (TAC);
"LSALT" means lowest safe altitude;
"navigation tolerance area", in relation to a route segment, is the area calculated in accordance with section 5.

Lowest safe altitudes
2.1 Subject to paragraph 2.2, if the LSALT for a route segment has not been determined under paragraph 178 (1) (a) of the Civil Aviation Regulations, the LSALT for the route segment is the highest of the following altitudes, rounded up (if necessary) to the next 100 feet:
 (a) 1,000 feet above the top of the highest reported obstacle in the effective area;
 (b) if an aeronautical topographical chart is used to calculate the lowest safe altitude—1,000 feet above the height of the corrected highest terrain in the effective area;
 (c) 1,500 feet above mean sea level.

2.2 If the LSALT for a route segment has not been determined under paragraph 178(1)(a) of the Civil Aviation Regulations and is to be determined by reference to Grid LSALTs, the LSALT for the route segment is the highest grid LSALT shown for the effective area.

Effective area—meaning
3.1 If the LSALT for a route segment is determined by reference to the Grid LSALTs shown on an ERC or TAC, the effective area of the route segment is the area of the earth's surface represented by all the grid squares over which the navigation tolerance area determined in accordance with paragraph 5.1 is shown to extend wholly or in part.

3.2 If the LSALT for a route segment is determined by any other means, the effective area of the route segment is the area that comprises:
 (a) the navigation tolerance area of the route segment, determined in accordance with paragraph 5.2; and
 (b) a 5-mile wide