AUTOFLIGHT MENU A/THR 1/33 AUTOFLIGHT MENU A/THR 2/33 We will now look at how the Flight Guidance achieves its automatic thrust control function: the Auto THRust system, or A/THR. AUTOFLIGHT MENU A/THR 3/33 e.g. MAX CLB & IDLE e.g. Cruise & Approach Thrust adjusted to maintain target speed/Mach The A/THR can work in two different modes: - SPEED mode: The A/THR continuously adjusts the thrust in order to maintain a target speed or Mach, e.g. during cruise or approach. - THRust mode: The A/THR sets a given thrust e.g. MAX CLB or IDLE. Autothrust SPEED mode Steady Thrust THR mode AUTOFLIGHT MENU A/THR 4/33 The A/THR modes are automatically linked to AP/FD vertical modes: - When AP/FD vertical mode controls a trajectory, e.g. altitude hold, V/S ,G\S…, the ATHR is in SPEED mode. - When AP/FD vertical mode adjusts the A/C pitch in order to keep a target speed or Mach, e.g. climb, descent…, the A/THR is in THR mode. Autothrust SPEED mode THR mode TRAJECTORY SPD/MACH TARGET AUTOFLIGHT A/THR 5/33 The main pilot controls to the A/THR are the THRUST LEVERS. On the A320, the A/THR does not backdrive the thrust levers while it adjusts the thrust. Let’s have a closer look at them. MENU AUTOFLIGHT MENU A/THR 6/33 AUTOFLIGHT MENU A/THR 7/33 IIDDLLEE AUTOFLIGHT MENU A/THR 8/33 CCLLIIMMBB IIDDLLEE AUTOFLIGHT MENU A/THR 9/33 CCLLIIMMBB FFLLEEXX//MMCCTT IIDDLLEE AUTOFLIGHT A/THR 10/33 CCLLIIMMBB FFLLEEXX//MMCCTT TTOO//GGAA When the A/THR is OFF, the crew controls the thrust, as usual, by moving the thrust levers over a quadrant. For forward thrust this quadrant carries four physical detents or stops which are: - IDLE - CL for Max Climb Thrust, - FLEX/MCT for FLEX thrust at TO or Max Continuous Thrust, - TO GA for Max Take Off or Go Around thrust MENU IIDDLLEE AUTOFLIGHT MENU A/THR 11/33 The A/THR can only work when the thrust levers are set forward of the IDLE detent. If the thrust levers are set by the pilot in the reverser segment, the A/THR can not operate. AUTOFLIGHT MENU A/THR 12/33 When A/THR is ON, the thrust lever position determines the maximum thrust which can be commanded by the autothrust. For example, to accelerate in SPEED mode. On the “thrust” gage, that we will talk about in the engine chapter, the thrust lever position is shown, indicating the thrust available to the A/THR for normal operation. ““TThhrruusstt”” ggaaggee TThhrruusstt lleevveerr ppoossiittiioonn A/THR Available thrust AUTOFLIGHT MENU A/THR 13/33 The A/THR has three states. It can be either: - Disconnected, or OFF, - Armed, ready to be set to ON by a specific pilot action on the thrust levers, or, - Active, or ON. Let’s see these states in more detail. ARMED ACTIVE DISCONNECTED AUTOFLIGHT A/THR 14/33 Wee aarree ttaaxxiiiinngg ttoo tthhee rruunnwaayy...... MENU AUTOFLIGHT A/THR 15/33 Because we are on the ground the A/THR is necessarily disconnected. This is confirmed by the absence of any A/THR related indications on the FMA and by the extinguished A/THR pb on the FCU. Thrust is manually adjusted by the crew as required to taxy the aircraft. MENU AUTOFLIGHT MENU A/THR 16/33 You are cleared for takeoff. The Pilot Flying must manually set the thrust levers to FLEX or TOGA to initiate the take off roll. Clliicckk oonn tthhee tthhrruusstt lleevveerrss ttoo iinniittiiaattee tthhee TTO rroollll.. AUTOFLIGHT MENU A/THR 17/33 You are cleared for takeoff. The Pilot Flying must manually set the thrust levers to FLEX or TOGA to initiate the takeoff roll. Noo.. Clliicckk oonn tthhee tthhrruusstt lleevveerrss ttoo iinniittiiaattee tthhee TTO rroollll.. AUTOFLIGHT MENU A/THR 18/33 You are cleared for takeoff. The Pilot Flying must manually set the thrust levers to FLEX or TOGA to initiate the takeoff roll. Noo.. Clliicckk oonn tthhee tthhrruusstt lleevveerrss ttoo iinniittiiaattee tthhee TTO rroollll.. AUTOFLIGHT A/THR 19/33 As soon as the thrust levers are set in the TOGA detent the FMA shows: A/THR blue - indicating that A/THR is armed, MAN TOGA white - indicating that the pilot manually controls the thrust via the thrust levers set in TOGA. Note: TOGA is the maximum thrust available for TO. MENU AUTOFLIGHT A/THR 20/33 At the same time, on the FCU, the A/THR pb light illuminates in green. The fact that the A/THR is armed means that it is ready to be turned ON by a pilot action on the thrust levers. Note that when the A/THR is armed the pilot has manual control on the thrust with the thrust levers MENU AUTOFLIGHT MENU A/THR 21/33 Crossing the Thrust Reduction Altitude (THR RED ALT) the pilot must manually set the thrust levers to CL detent. On the FMA a flashing “LVR CLB” prompts the pilot to set the thrust levers back into CL detent. Set climb thrust now. Clliicckk oonn tthhrruusstt lleevveerrss ttoo sseett CLLB tthhrruusstt.. AUTOFLIGHT MENU A/THR 22/33 Crossing the Thrust Reduction Altitude (THR RED ALT) the pilot must manually set the thrust levers to CL detent. On the FMA a flashing “LVR CLB” prompts the pilot to set the thrust levers back into CL detent. Set climb thrust now. Noo.. Clliicckk oonn tthhrruusstt lleevveerrss ttoo sseett CLLB tthhrruusstt.. AUTOFLIGHT MENU A/THR 23/33 Crossing the Thrust Reduction Altitude (THR RED ALT) the pilot must manually set the thrust levers to CL detent. On the FMA a flashing “LVR CLB” prompts the pilot to set the thrust levers back into CL detent. Set climb thrust now. Noo.. Clliicckk oonn tthhrruusstt lleevveerrss ttoo sseett CLLB tthhrruusstt.. AUTOFLIGHT A/THR 24/33 Notice that on the FMA: A/THR white - indicates that the A/THR is ON. THR CLB green - indicates that the A/THR is in THRrust mode. Since the thrust levers are set in the CL detent, and the AP commands a climb mode, the A/THR commands THRUST CLIMB. The white boxes around the modes highlight the fact that a mode change has occurred on the FMA. NOTE: The AP1 vertical mode adjusts the pitch to maintain the target speed which is V2+10. MENU AUTOFLIGHT MENU A/THR 25/33 In normal operation when A/THR is ON, the levers are left in the CL detent throughout the flight until the flare. The A/THR adjusts the thrust, as required, between IDLE and MAX CLB; note that the thrust levers are not backdriven by the A/THR and stay in the CL detent. If, at any moment, the pilot needs some additional thrust, he will push the thrust levers forward from CL detent. He will then manually control the thrust. AUTOFLIGHT A/THR 26/33 When the aircraft reaches the target altitude, AP/FD gets in ALT mode; the A/THR switches to SPEED mode, as indicated on the FMA. In this mode the A/THR continuously adjusts the thrust to maintain the target speed. A/THR is also in SPEED mode when AP/FD vertical modes are V/S or FPA, G/S and generally during the approach. MENU AUTOFLIGHT A/THR 27/33 We are now in approach, just before flare. You handfly the aircraft with the Autothrust engaged. MENU AUTOFLIGHT MENU A/THR 28/33 Note that the A/THR is in SPEED mode. During a hand flown FLARE, the pilot has to reduce the thrust for landing. He will do so by bringing the thrust levers back to IDLE at about 20ft. Note: if he does not do so, the A/THR will increase thrust to maintain the speed. A “RETARD” auto call out comes up at about 20ft as a reminder to retard the thrust levers. Clliicckk oonn tthhee tthhrruusstt lleevveerrss ttoo sseett tthheemttoo iiddllee.. AUTOFLIGHT MENU A/THR 29/33 Note that the A/THR is in SPEED mode. During a hand flown FLARE, the pilot has to reduce the thrust for landing. He will do so by bringing the thrust levers back to IDLE at about 20ft. Note: if he does not do so, the A/THR will increase thrust to maintain the speed. A “RETARD” auto call out comes up at about 20ft as a reminder to retard the thrust levers. Noo.. Clliicckk oonn tthhee tthhrruusstt lleevveerrss ttoo sseett tthheemttoo iiddllee.. AUTOFLIGHT MENU A/THR 30/33 Note that the A/THR is in SPEED mode. During a hand flown FLARE, the pilot has to reduce the thrust for landing. He will do so by bringing the thrust levers back to IDLE at about 20ft. Note: if he does not do so, the A/THR will increase thrust to maintain the speed. A “RETARD” auto call out comes up at about 20ft as a reminder to retard the thrust levers. Noo.. Clliicckk oonn tthhee tthhrruusstt lleevveerrss ttoo sseett tthheemttoo iiddllee.. AUTOFLIGHT A/THR 31/33 Thrust levers are now set to idle. This turns the A/THR OFF. Note that: On the FMA, A/THR white is not displayed any more. The FMA A/THR column is blank. On the FCU, the A/THR pb is now extinguished. MENU AUTOFLIGHT A/THR 32/33 We have just seen one way to turn the A/THR OFF, by setting the thrust levers back to IDLE. The other way to turn the A/THR OFF is to press either one of the two A/THR instinctive disconnect pbs located on the thrust levers. You will be shown the procedure to turn the A/THR ON and OFF in the simulator. NOTE: Pressing at least one pb for more than 15 seconds will inhibit the A/THR for the remainder of the flight. MENU AUTOFLIGHT MENU A/THR 33/33 When the A/THR is OFF during flight, in order to turn it ON again, press the A/THR pb on the FCU with the thrust levers in or below CL detent. NOTE: You can disconnect the A/THR by pressing the A/THR pb on the FCU. This is NOT the standard recommended procedure. NEXT MMoodduullee ccoommpplleetteedd AUTOFLIGHT MENU A/THR 34/33 LLIISSTTOOFFSSUUBBJJEECCTTSS EXIT AUDIO GLOSSARY FCOM RETURN PPRREESSEENNTTAATTIIOONN TTHHRRUUSSTTLLEEVVEERRSS DDIISSCCOONNNNEECCTTIIOONN//RREEAACCTTIIVVAATTIIOONN MMOODDEESSOOFFOOPPEERRAATTIIOONN作者: bocome 时间: 2011-7-31 10:01:46