Altimeter Setting Procedures

Altimeter Setting Policy

The altimeter setting procedures provide adequate vertical separation between aeroplanes and, in conjunction with correct navigation procedures, ensure adequate terrain clearance during all phases of flight. Before leaving the ramp the pressure scales of all altimeters shall be set to the actual QNH of the aerodrome.

For altimeter tolerances refer to OM Part B.
When changing an altimeter setting, each pilot will call out the new setting and check altitudes. Altimeter setting call-outs are explained in OM Part B and FCOM.

Pressure altimeters are calibrated to indicate true altitude under International Standard Atmosphere (ISA) conditions. Any deviation from ISA will therefore result in an erroneous reading on the altimeter. The altimeter error may be significant under conditions of extremely cold temperature and appropriate corrections should be applied. Refer to OM Part B for specific procedures.
For IFR Flight Level tables (including metric system) refer to OM Part C.

Take-off and Climb

For take-off all shall altimeters shall be set on QNH. When passing the transition altitude, all altimeters shall be set to STANDARD (1013.25 hPa) and baro-settings and altitude readings shall be crosschecked.

In case cleared flight level is very close to transition altitude and QNH is much lower than 1013 hPa, altimeters may be set to STANDARD before crossing transition altitude. This is to prevent initial flight level bust while still on QNH. Where this procedure is applied, it must be anticipated and briefed prior to departure.

Pilot self-checking and cross-monitoring in all matters relating to vertical clearances is therefore essential. Again this is particularly important when QNH is low and the difference between it and the standard pressure setting (translated into vertical distance) is potentially even more safety critical.

Cruise

If cruising at or below transition altitude, primary and stand by altimeters shall be set to QNH and baro-settings and altitude readings shall be crosschecked.

If cruising above the transition altitude, primary and stand by altimeter shall be set to STANDARD (1013.25 hPa).

Descent & Approach

When cleared to an altitude with no flight level constraints, all altimeters shall be set to local QNH. For approach and landing all altimeters shall be set to local QNH.

Type of Altimeter Settings

As indicated below, each setting will result in a altimeter indication which provide a measure of the vertical distance with regard to the ICAO Standard Atmosphere (ISA) above the particular reference datum shown.

Note: QNH shall be the sole reference for take-off, approach and landing.

Altimeter Serviceability Checks

• During cockpit preparation the pressure scales of all altimeters shall be set to the actual QNH of the aerodrome - they must read to be within the type specific tolerances as defined in OM Part B;
• The altimeter indications thus obtained shall be observed and checked against the elevation of the aerodrome;
• When the altimeter does not indicate the reference elevation or height exactly, but is within the tolerance specified in the OM Part B, no adjustment of this indication shall be made at any stage of the flight. Furthermore, any error that is within tolerance noted during pre-flight check on the ground shall be ignored by the flight crew during entire flight;
• After each setting of altimeters the readings on the flight deck shall be compared. This shall include the standby and metric (if installed) altimeters;
• If an altimeter indication is not within the specified tolerance follow the procedure outlined in the OM Part B.

QFE and / or Metric Altimeter Setting Procedure

Refer to OM Part B and OM Part C.
In certain States dimensions used are metric. Charts for these aerodromes indicate all vertical distances as altitudes in feet (QNH), with conversion to heights in feet (QFE) and/or metres (QFE).

ATC instructions and flight crew reports concerning vertical navigation below transition height/level are expressed in »metres QFE« (height).

For departure, for en route flying at or below transition altitude/level and for intermediate and final approach, both altimeters shall be set to QNH and the QNH/QFE conversions used to establish and report vertical position.

A third altimeter (which may be metric) should be set to QFE for monitoring.

Altitude Alerting System Procedures

All The Company aircraft have an automatic altitude alerting system.

Refer to OM Part B and FCOM for details.
The purpose of the altitude alerting system is to alert the flight crew by the automatic activation of a visual and/or an aural signal when the aeroplane is about to reach or is leaving the preselected altitude/flight level. The system and its operation shall ensure an accurate altitude adherence during all phases of the flight:

• During climb, the altitude alerting system shall be set to the altitude/flight level that the aeroplane is cleared to during climb. When climb constraints are part of a departure clearance, constraint altitude(s) may be set in the altitude alerting system (selected altitude window) even though such constraints are also entered in the FMS (as applicable) – refer to OM Part B;
• During cruise, the altitude alerting system shall be set to the assigned cruising level;
• During descent, the altitude alerting system shall be set to the altitude/flight level the aeroplane is cleared to descent. When descent constraints are part of a arrival clearance, constraint altitude(s) may be set in the altitude alerting system (selected altitude window) even though such constraints are also entered in the FMS (as applicable) – refer to OM Part B;
• During a visual approach the altitude alerting system shall be set initially to the minimum terrain clearance altitude and later on to traffic pattern altitude. Latest when passed 1.000 ft AAL, the altitude alerting system shall be set to the applicable missed approach altitude;
• When it is necessary to change the selected altitude, the change must be cross checked by the other pilot;
• In case of an instrument approach the missed approach altitude shall be set in the altitude alerting system once established on final approach.

The use of the altitude alerting system does not in any way release the flight crew from the responsibility of ensuring that the aeroplane levels off or will be levelled off at the correct altitude or flight level.

If there is anything other than total agreement by both pilots during the verification process, contact ATC immediately to resolve the conflict. To avoid confirmation bias when seeking cleared altitude/level verification from ATC use open phrase (e.g. »CONFIRM CLEARED ALTITUDE«, or »SAY AGAIN CLEARED FLIGHT LEVEL«).

Ground Proximity Warning System Procedures

The Ground Warning Proximity System (GPWS) is designed to alert pilots that the aeroplane position in relation to the terrain is abnormal and, if not corrected, could result in a controlled flight into terrain (CFIT). An Enhanced GPWS (EGPWS) has an additional feature of comparing the computed present position of the aircraft with a Terrain Database.

All The Company aircraft shall be fitted with an EGPWS or its derivative. The following constitute policy on the EGPWS:

• A CFIT escape manoeuvre shall be initiated in IMC or at night, or if cause of warning cannot be identified immediately;
• When a warning occurs during daylight VMC conditions, if positive visual verification is made that no hazard exists, the warning may be considered cautionary;
• The EGPWS must be ON from take-off until landing;
• The EGPWS may not be deactivated (by pulling the circuit breaker or use of the relevant switch) except when specified by approved MEL/OM Part B procedures;
• Any EGPWS activation must be reported via ASR system whether genuine or spurious;
• Where such activation indicates a technical malfunction of the system an appropriate entry should be made in the Aircraft Technical Log.

EGPWS terrain mode should be routinely displayed to PF during climb/descent over areas with high terrain. If because of the weather radar display is required then PF/PNF shall discuss about displaying radar and terrain mode, as applicable.