In low temperature, the true altitude is lower than the indicated altitude, resulting in a lower-than-anticipated terrain separation and in a possible terrain clearance hazard (as illustrated by Figure 1, for a – 40 degree Celsius OAT).
True
Altitude
2000 ft
1600 ft High OAT Standard OAT Low OAT
Figure 1
Effect of OAT on True Altitude
Flying into low temperature has the same effect as flying into a low-pressure area; the aircraft is lower than the altimeter indicates.
These effects are summarized and illustrated in Table 2, featuring a well-known aviation golden rule:
Atmospheric Pressure High Low Look out below
OAT Warm Cold
Table 2
Atmospheric Pressure and Temperature Effects on True Altitude
Terrain Awareness – When and How ?
Page 6
AIRBUS INDUSTRIE
Flight Operations Support
Airport charts:
Review and discuss the following terrain-awareness-items using the airport charts:
.
Approach and runway lighting, and other expected visual references; and,
.
Specific hazards (such as man-made obstacles, as applicable).
If another airport is located in the close vicinity of the destination airport, relevant details or procedures should be discussed for awareness purposes.
Use of automation:
Discuss the intended use of automation for vertical and lateral navigation:
.
Use of FMS-managed guidance or selected modes; and,
.
Use of precision approach, constant-angle or step-down non-precision approach, as required.
Descent Management and Monitoring
Before entering the terminal area (TMA), check the FMS navigation accuracy (using navaids raw data) against the applicable criteria for terminal or approach navigation.
If the accuracy criteria for lateral FMS navigation in terminal area and/or for approach are not met, revert to a selected lateral mode with ND in ROSE or ARC mode.
If flying with IRS ONLY navigation, do not descend below the sector MSA without positive confirmation of the aircraft position, using navaids raw data.
Standard Arrival - STAR
Be aware of whether or not the arrival is radar-monitored by the ATC.
Maintaining a sterile cockpit when below 10 000 ft or below the sector minimum safe altitude (MSA), particularly at night or in instrument meteorological conditions (IMC).
Getting to Grips with Approach-and-Landing Accidents Reduction
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