(b)
Secondary F-PLN created via SEC INIT A secondary F-PLN created by SEC INIT is treated as an active primary flight plan before engine start. Performance calculations are totally independent of the current active F-PLN, clock time, engine status, A/C characteristics, etc : they are based on the weights, ZFWCG, CRZ FL, cost index, etc. entered on the SEC INIT or SEC PERF page, and normal 2-engine operation is assumed. Predictions are provided for display on the following MCDU pages:
-
SEC INIT: fuel predictions,
-
SEC F-PLN, VERT REV, SEC PERF: same as for a secondary F-PLN created via COPY ACTIVE (HMs are ignored by predictions since entry fix is not sequenced).
R **ON A/C 106-149, 151-199, 211-299, 301-399, 401-499,
Post SB 22-1089 For A/C 151-199,211-212,
PERFORMANCE/VERTICAL FUNCTIONS - DESCRIPTION AND OPERATION
__________________________________________________________
1. General
_______ The vertical functions and performance computations are available from a defined lateral and vertical flight plan, as described in 22-71-00. They enable: - optimization of the vertical profile inside all limitations (such as speed
envelope and constraints)
-estimation of fuel consumption and corresponding time
-guidance according to the optimized vertical profile. Flight phases enable flight plan sharing in order to isolate different computations and guidance modes. They are given with appropriate switching logics. Then speed generation is described, with first speed envelope, reference and optimized speeds to be used in predictions and guidance in MANAGED SPEED CONTROL mode (speed management mode). And then follows manual speed mechanization for Multipurpose Control and Display Unit (MCDU) preselection, Flight Control Unit (FCU) display and guidance in SELECTED SPEED CONTROL mode (speed selection mode). The vertical flight plan management deals with computation of predictions and vertical guidance. This can be done with different assumptions, dependent on the engaged modes on the FCU: lateral, vertical and speed controls may be engaged in MANAGED or in SELECTED modes. For each combination are given consequences on modes and submodes which are activated and displayed on the Flight Mode Annunciator (FMA) section of the Primary Flight Display (PFD); are also given associated rules and predictions, then special rules to rejoin the vertical path. Additional computations are also given, which are used by previous functions in normal cases (altitude, fuel, weight management) or in special cases (engine out, holding speeds, alternate predictions).
2. System Description
__________________
A. Flight Phases
(1)
Introduction The flight plan (F-PLN) is divided in several flight phases for which specific operations, predictions and guidance are defined. (Ref. Fig. 001) These flight phases are for the ACTIVE primary F-PLN:
-preflight
-takeoff (from origin to accel altitude)
-climb (from accel altitude to Top of Climb (T/C))
-cruise (from Top of Climb to Top of Descent (T/D))
-descent (from Top of Descent to deceleration point)
-approach (from deceleration point to destination)
-go around (missed approach points)
-done. Except for the first and last ones, each of these flight phases is displayed in the title of the PERF page which is accessed when the PERF key is pushed. When present flight phase is PREFLIGHT or DONE, the PERF key action gives access to the TAKEOFF PERF page. The same display of the flight phase is repeated in the title of the PROG page. (Ref. Fig. 002) See following figure for a typical vertical trajectory where all phases are involved only once. All vertical elements mentioned through the vertical profile are defined in 22-71-00.
(2)
Flight phases switching Switching from one phase to another one is performed when the corresponding conditions are met, as explained below. The number of available transitions is greater than the number of flight phases. (Ref. Fig. 001) Most of the phases can be accessed not only from the normal preceding one, but also from at least another one. For each phase, all possible other ones from which a transition exists (to the described phase) are listed in the following paragraph.
(a)
PREFLIGHT phase This flight phase becomes active when the INIT or the PERF key is pushed in DONE phase.
(b)
TAKEOFF phase It becomes active from DONE or PREFLIGHT phase when engine rate reaches the takeoff rate and PITCH TAKEOFF mode is engaged, or ground speed reaches the takeoff rate.
Flight Plan Definition
Figure 001
Flight Phase Display on PERF and PROG Pages 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：A320飞机维护手册 AMM AUTO FLIGHT 自动飞行4(2)
