Transition altitude
This is the altitude at which the altimeter barometric setting
is changed from the local value to standard (1013.2 mb).
It is only defined during takeoff, climb and go around phases.
The pilot may view on performance pages the transition
altitude.
This altitude may be derived from data base in the airport
record. Once an airport is defined the altitude is displayed
if it is defined in airport record.
If not, there are brackets to allow pilot entry.
(Ref. Fig. 011)
During takeoff, the transition altitude is equal to the
transition altitude displayed on takeoff page if any.
Otherwise it is undefined.
At transition from Descent or Approach to climb
or Approach to go around, it is equalized to the Trans alt
which was displayed on the approach page just before phase
transition if there was, else it remains undefined.
At transition from takeoff, go around or cruise to climb, it
remains what it was just before phase transition (it may be
defined or undefined).
Transition level:
Progress Page (on Descent)
Figure 015
It is the flight level at which the altimeter barometric
setting is changed from the standard (1013.2 mb) to the local
value for the airport.
It is only defined for descent and approach.
During descent and approach if there is a transition altitude
and a QNH value entered by pilot displayed on the Performance
Approach page, it is computed from that value as follows (if
not, it is undefined).
(Ref. Fig. 016)
TRANS level is equal to :
1 ___ Max (Trans alt, trans alt + delta alt (QNH(CDU)) 100
As the transition altitude, the transition level may be derived from data base or from pilot entry.
8 COST INDEX
_ R This economical criteria enables the speed optimization along R the whole flight plan. It is defined as the ratio of time cost
and fuel cost so that the value of 0 means "minimum fuel" optimization and 999 means "minimum time" optimization. Any value may be defined by each company for each route according to its performance policy. The value is defined during ACTIVE flight plan initialization (field 5L on INIT A page). (Ref. Fig. 014) In flight, this value may be modified for climb, cruise and descent phases by the pilot through the appropriate performance page. This value may be modified even when an Engine Out occurs.
(3) SECONDARY F-PLN The pilot may define a SECONDARY flight plan by having access to the SEC INDEX page after action on the SEC F-PLN mode key. The SECONDARY F-PLN is defined as the primary flight plan with the same kinds of lateral and vertical elements. The pilot may perform lateral and vertical revisions but there is no temporary situation as for the primary F-PLN.
R In this secondary mode, the available pages are:
-INIT
-F-PLN with access to lateral and vertical revision pages
-Perf
(Ref. Fig. 017, 018)
Performance Approach Page (when VOR approach selected at magnetic airport)
Figure 016
SEC INDEX Page
Figure 017
SEC F-PLN Page A at Origin
Figure 018
B. Initialization
(1) ACTIVE F-PLN
(a) INIT A page The initialization is performed on the INIT A page. Example of INIT A pages are shown in figures: (Ref. Fig. 019, 020)
1_ Access
- INIT mode key on MCDU keyboard when the aircraft is in the
PREFLIGHT or DONE flight phases. If the INIT mode key is
pressed when in any other flight phase, a message (NOT
ALLOWED) is displayed,
- left or right arrow from INIT B page,
- 6L (RETURN) or 6R (INSERT) LS key from Route Selection page,
- if the INIT A page is displayed when the flight phase
transitions from PREFLIGHT or DONE to TAKE OFF, CLB, CRZ,
DES, or APPR, the display changes to the F-PLN A page.
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