Copied straight from my FCOM bulletin regarding RNAV GNSS approaches:
Cold Temperature Altitude Corrections
In the design of RNP APCH APV procedures with LNAV/VNAV minima, the
allowable temperature range is specified and the procedure design accounts for
operations and obstacle clearance for any temperature within the specified range
on the approach plate. If the actual temperature is within the specified temperature
range the pilot can fly the RNP APCH APV procedure and no temperature
corrections are needed. If the actual temperature is outside the specified
temperature range, the crew cannot fly the RNP APCH APV procedure.
In this case an RNP APCH NPA procedure with LNAV minima may be used and
the altitude constraints at FMC waypoints on the final approach need to be
modified according BOM 8.3-3, as the procedure design does not take
temperature variations into account.
For both RNP APCH APV (LNAV/VNAV minima) and RNP APCH NPA (LNAV
minima) approaches, the initial, intermediate and missed approach segment flight
plan fixes need to be corrected for cold temperature.
Note: DA/MDA must also be corrected for low temperatures
Makes perfect sense to me!!
Note: in case the temp is below the min temp specified, you can still fly the approach with LNAV and VNAV modes!!! Just not to LNAV/VNAV minima, but to LNAV minima raised for cold wx corrections.
(When temp is below 0 but above temp specified for LNAV/VNAV minima, you still have to raise the LNAV/VNAV minima)
Last edited by flyburg; 20th Dec 2015 at 08:45.