Vertical Profile Navigation Mode Review

Agenda Review Mode Overview Performance Modes Levels of Automation FMA’s Review Mode Overview Vertical Profile Performance Modes Levels of Automation VNAV General Concepts Operation Here are the topics for this lesson.

You fly the 767 primarily using the Autoflight Control System You fly the 767 primarily using the Autoflight Control System. Manual flying is at a minimum.

Autoflight Control System (AFCS) The autoflight control system contains the autopilot/flight director system, the thrust management system, ……

You use the Mode control panel for aircraft control using the autopilot, or to control the flight director guidance for manual flight.

Lighted switch indicates mode acceptance by the FCC, not engagement Indications for the engaged modes are the flight mode annunciations.

You need to include in your scan the FMA’s. To maintain positive control of the airplane, you need to always be aware of the engaged mode AND know what that mode does. You need to always be aware of the engaged modes to know what the airplane is doing or what the guidance for the flight directors will be. You need to always be aware of the engaged modes to know what the airplane is doing or what the guidance for the flight directors will be.

Asiana example do you know what IDLE mode will do?

Flight Modes Annunciations Thrust Pitch Roll

Autoflight Modes

Autoflight Limit Modes

Automation Levels 3. Automatic Modes 1. Pilot assist modes The more automated, the less direct control you have 2. Pilot controlled command modes Different modes offer different levels of automation. The more the automation takes over, the more your workload is reduced… unless it isn’t doing what you expect it to do. To minimize this, you need to have an understanding of how the automation works in different situations.

Another way to look at the FD Obviously it is vital to understand the modes indicated on the ADI. Interpreting the indicated modes lets you know how the airplane is controlled and what it will do. Some modes such as LNAV and VNAV have more hidden rules. You must understand those rules to know how the airplane is controlled.

Mode Axis Control Modes can control one or more axis. For instance when you select VNAV or FLCH you engage both pitch and thrust. Selecting vertical speed only engages pitch.

Thrust Only

Pitch Only

Roll Only

Thrust & Pitch

Pitch & Roll

Thrust, Pitch & Roll

Computer Brains TMC FMC’s FCC’s The thrust management computer, flight management computers, and flight control computers are the main computers calculating the control laws for flight guidance.

Thrust Mode Indicator This mode indicates how the thrust is controlled.

Thrust Management System The thrust management system controls the autothrottle. A thrust management computer actuates the throttles based on inputs from the mode control panel or from FMC commands when you engage VNAV.

TMC Modes Notice the A/T arm switch is right above the commands to engage the TMC in THR (N1) or SPD modes. The TMC moves the throttles as required to maintain the limit N1 in THR mode or the reference speed in SPD mode.

Flight Path Modes These two modes determine the guidance of the flight path. The flight director indicates the desired pitch and roll.

Who’s Controlling Mode If you see FD, maybe it’s a good idea to grab ahold of this thing (if you haven’t already) This mode indicates who is actually following the flight path guidance; you or the autopilot.

Performance Modes Now that we had a short mode review, let’s look at the performance modes.

Power + Pitch = Performance Vertical Guidance Remember when you were just learning this stuff Power + Pitch = Performance FMC’s When you enter SID’s, STAR’s and a cruise altitude, you provide the FMC with a set of vertical legs. These legs specify the type of performance desired to control airplane’s pitch & thrust axes within constraints of flight plan.

Another way to look at the FD

Three Flight Segments The Vertical profile is partitioned into three flight segments.

Vertical path on elevator Speed on elevator For speed on elevator, the speed is maintained until the specified target altitude is reached. Speed on elevator is used for climb, cruise climb, cruise descent and speed reversion with respect to the descent path.

Vertical (performance) legs Like lateral legs

Vertical (Performance) Plan Legs: A leg may use more than one type of control mode Speed/Thrust Airspeed on elevator thrust on throttle V-Path/Speed Vertical path on elevator airspeed on throttle Cruise Descent Airspeed on elevator thrust to computed value then HLD V-Path/Idle Vertical path on elevator throttle IDLE speed control through speed brakes, or autothrottle mode request, or manual throttle if A/T disengaged Speed/Idle Airspeed on elevator throttle to computed idle, then airmass performance Speed Reversion Backup for V-Path/Idle to Speed/Idle Gamma Hold Backup for speed on elevator - prevents inadvertent climb in descent or descent in climb - controls to fixed descent or climb rate with elevators Vertical Speed Submode of speed on elevator in selected E/O driftdown cases. Elevators control descent rate to 300 fpm and throttle controls speed.

Five flight phases to be predicted: Takeoff – engine start, taxi and takeoff through cleanup Climb – cleanup to cruise altitude Cruise – until T/D Descent – when airplane leaves cruise altitude, descending to destination to approach Approach – initial flap extension point to touchdown

A lot is going on in the computer that is not annunciated A lot is going on in the computer that is not annunciated. The VNAV switch is OVERLOADED according to human factor design.

When reaching cruise altitude

Speed changes in VNAV during cruise Active speed Execute ENG OUT or LRC Execute CDU entry Or Speed Intervention

Determining impact of speed change During Speed intervention

Descent

Non-normal An autopilot caution occurs if the autopilot stops operating correctly, but does not disconnect.

A yellow line crosses the mode annunciation A yellow line crosses the mode annunciation. Also the related flight director bar(s) disappear.