320系列机组课程自动飞行保护
**** Hidden Message ***** AUTOFLIGHT MENU Protections 1/33<BR>AUTOFLIGHT MENU<BR>Protections 2/33<BR>An other aspect of the FMGS is the assistance provided to<BR>the pilot to keep the flight safe and within the flight envelope.<BR>This assistance covers:<BR>- The engine failure compensation,<BR>- The low speed protections, and,<BR>- The AP/FD mode reversions.<BR>Let’s look at some of these “protections” in detail.<BR>AUTOFLIGHT MENU<BR>Protections 3/33<BR>In case of an engine failure with AP ON, the FMGS ensures an automatic yaw<BR>compensation in all modes.<BR>This is achieved by the FAC, using the yaw damper at take off and go-around and<BR>the automatic rudder trim in all modes.<BR>Furthermore, the AP/FD SRS pitch mode adjusts automatically the reference<BR>target guidance speed in case of an engine failure at take off or go-around.<BR>NAV<BR>ENGINE FAILURE<BR>COMPENSATION<BR>AUTOFLIGHT MENU<BR>Protections 4/33<BR>Low speed protection is achieved by the following features:<BR>- The A/THR SPEED mode,<BR>- The LOW ENERGY warning,<BR>- The ALPHA FLOOR protection, and,<BR>- The WINDSHEAR protection<BR>LOW SPEED<BR>PROTECTIONS<BR>AUTOFLIGHT MENU<BR>Protections 5/33<BR>When the A/THR is ON and in SPEED mode:<BR>- If the speed target is MANAGED (driven by the FMS) and the speed target<BR>is below the actual maneuvering speed, here F, the A/THR will not allow the<BR>speed to decrease below this maneuvering speed.<BR>- If the speed target is SELECTED (by the pilot on the FCU) and the speed<BR>target is below VLS, the A/THR will not allow the speed to decrease below VLS.<BR>MANAGED<BR>SPEED<BR>SELECTED<BR>SPEED<BR>A/THR<BR>SPEED MODE<BR>AUTOFLIGHT MENU<BR>Protections 6/33<BR>LOW ENERGY<BR>WARNING<BR>If, for any reason such as turbulence, shear, A/THR OFF… the A/C speed drops<BR>significantly below VLS, a repetitive “SPEED SPEED SPEED” aural warning is<BR>automatically triggered by the FAC.<BR>It drives pilot’s eyes to the speed scale, so as to readjust thrust, for example. This<BR>warning takes into account the A/C deceleration rate and current flight path angle which<BR>explains the “LOW ENERGY” wording.<BR>It is available when the A/C is on departure and arrival: between 100 ft and 2000ft RA and<BR>in configuration 2, 3 or FULL (with Flaps extended).<BR>AUTOFLIGHT MENU<BR>Protections 7/33<BR>ALPHA FLOOR<BR>PROTECTION<BR>If the A/C speed still drops more (below the low energy warning) and the angle of attack<BR>increases above a given threshold, the “ALPHA FLOOR” function of the A/THR is<BR>triggered. The A/THR commands full thrust, I.e. TOGA thrust.<BR>AUTOFLIGHT MENU<BR>Protections 8/33<BR>ALPHA FLOOR<BR>PROTECTION<BR>The angle of attack threshold which triggers the “ALPHA FLOOR” is processed by the<BR>FAC as a function of A/C parameters such as configuration, deceleration rate …<BR>When ALPHA FLOOR is triggered:<BR>- A/THR is turned ON (if it was previously OFF), indicated by a white A/THR on the FMA,<BR>- A. FLOOR in green is displayed as the A/THR mode.<BR>The ALPHA FLOOR function is available from lift off down to 100ft AGL.<BR>AUTOFLIGHT MENU<BR>Protections 9/33<BR>WINDSHEAR<BR>DETECTION<BR>If the A/C encounters windshear conditions, detected by the FAC, a red<BR>WINDSHEAR message is triggered on both PFD, associated with an aural<BR>“WINDSHEAR WINDSHEAR WINDSHEAR” warning.<BR>This windshear detection function is available from lift off to 1000ft at<BR>take off and from 1000ft down to 50ft during landing.<BR>AUTOFLIGHT MENU<BR>Protections 10/33<BR>The windshear protection is provided by the FMGC:<BR>- At takeoff and go around, with the AP/FD SRS vertical mode, which commands a pitch ensuring a<BR>minimum positive rate of climb, despite a potential speed drop.<BR>- In approach, with managed speed target: the speed target is automatically adjusted with wind<BR>variations, so as to ensure that the A/C ground speed does not drop below a minimum value (GS MINI).<BR>NOTE: If the angle of attack gets too high and reaches the fly by wire angle of attack protection, the AP<BR>disengages. The fly by wire maximum angle of attack protection assists the pilot to best react.<BR>AT TAKEOFF<BR>AND GO AROUND<BR>IN<BR>APPROACH<BR>WINDSHEAR<BR>PROTECTION<BR>AUTOFLIGHT MENU<BR>Protections 11/33<BR>Let’s now review the mode reversions of AP/FD and A/THR.<BR>The mode reversions are automatic mode changes:<BR>- Which ensure a flight envelope limit speed protection, or,<BR>- Which allow a comprehensive autoflight system behavior<BR>when the pilot modifies a target on the FCU.<BR>AUTOFLIGHT MENU<BR>Protections 12/33<BR>Let’s review the flight envelope limit speed protection with AP ON.<BR>Suppose you are in climb, and you select V/S +3000ft/mn while your target speed<BR>is 315kt. The target altitude is above A/C altitude. The performance capability of the<BR>aircraft does not allow such a high rate of climb.<BR>The AP pitches the A/C up to track +3000ft/mn. The A/THR, in SPEED mode, will<BR>command MAX CLB thrust since the A/C speed is decreasing.<BR>AP/FD REVERSION:<BR>V/SOPEN<BR>AUTOFLIGHT MENU<BR>Protections 13/33<BR>When the A/C speed reaches VLS+5kt, the AP vertical mode reverts to OP CLB<BR>and A/THR mode to THR CLB.<BR>The AP will pitch the A/C down to reaccelerate towards the 315kt target speed.<BR>This reversion ensures the flight envelope low limit speed protection.<BR>AP/FD REVERSION:<BR>V/SOPEN<BR>AUTOFLIGHT MENU<BR>Protections 14/33<BR>Suppose now that we have selected V/S +3000ft/mn, but with an altitude target<BR>below the A/C altitude.<BR>The AP pitches the A/C up to +3000ft/mn and speed decreases similarly.<BR>NOTE: On the FMA you can see that no ALT in blue is shown due to the target altitude<BR>being below the present A/C altitude with the A/C climbing.<BR>AP/FD REVERSION:<BR>V/SOPEN<BR>AUTOFLIGHT MENU<BR>Protections 15/33<BR>AP/FD REVERSION:<BR>V/SOPEN<BR>When the A/C speed reaches VLS + 5kt, the AP vertical mode reverts to OPEN<BR>DESCENT (OP DES) and the A/THR mode to THR IDLE.<BR>Remember:<BR>- With a target altitude above A/C altitude, the reversion is to OP CLB/THR CLB,<BR>- With a target altitude below A/C altitude, the reversion is to OP DES/THR IDLE.<BR>AUTOFLIGHT MENU<BR>Protections 16/33<BR>Let’s see an other case: we are in descent at 3000ft/mn, the target speed is 250kt<BR>and the target altitude is below the A/C altitude.<BR>The performance of the A/C is such that such a high rate of descent leads the<BR>A/C to accelerate...<BR>AP/FD REVERSION:<BR>V/SOPEN<BR>AUTOFLIGHT MENU<BR>Protections 17/33<BR>AP/FD REVERSION:<BR>V/SOPEN<BR>When the A/C speed reaches VMO/MMO - 5kt, the AP vertical mode reverts to OP<BR>DES and the A/THR mode to THR IDLE.<BR>The AP pitches the A/C up to recapture the 250kt target speed. This reversion<BR>ensures the flight envelope high limit speed protection.<BR>NOTE: Depending on A/C configuration, this reversion can occur at VLE + 4kt or VFE +<BR>4kt.<BR>AUTOFLIGHT MENU<BR>Protections 18/33<BR>Here is an other case: we are on approach, high above G/S, in landing<BR>configuration. V/S -2500ft/mn is selected to recover G\S from above, with a target<BR>altitude above the A/C current altitude. Notice that this V/S is actually quite high.<BR>The performance of the A/C is such that this high rate of decent leads the A/C to<BR>accelerate...<BR>AP/FD REVERSION:<BR>V/SOPEN<BR>AUTOFLIGHT MENU<BR>Protections 19/33<BR>AP/FD REVERSION:<BR>V/SOPEN<BR>When the A/C speed reaches VFE + 4kt, the AP vertical mode reverts to OP CLB and<BR>the A/THR mode to THR CLB (this is because target ALT is above A/C altitude).<BR>Hence, the A/C starts to climb with CLB thrust to recapture VAPP, which ruins your<BR>effort to fly back to the G/S.<BR>So, remember, if you are high above G/S, do not use an excessive down V/S...<BR>AUTOFLIGHT MENU<BR>Protections 20/33<BR>We have studied the flight envelope limit<BR>speed protections with AP ON. Let us now<BR>review other limit speed protections with FD<BR>ON and AP OFF (manual flight).<BR>AUTOFLIGHT MENU<BR>Protections 21/33<BR>FD REVERSION:<BR>OP DESV/S<BR>THR IDLE SPEED<BR>Suppose the A/C is manually flown with FD ON (AP OFF). The current vertical<BR>mode is OP DES, the A/THR one THR IDLE.<BR>In order to demonstrate the next reversion, the A/C is pitched up, disregarding<BR>the FD orders given by the FD bars.<BR>The speed decreases...<BR>NAV<BR>AUTOFLIGHT MENU<BR>Protections 22/33<BR>FD REVERSION:<BR>OP DESV/S<BR>THR IDLE SPEED<BR>When the A/C reaches VLS-2kt (or VLS-17kt with speed brakes extended), the<BR>A/THR reverts from THR IDLE to SPEED and thrust is readjusted to recapture the<BR>target speed.<BR>Simultaneously, OP DES reverts to V/S using the actual V/S value at the time of<BR>reversion.<BR>NAV<BR>AUTOFLIGHT MENU<BR>Protections 23/33<BR>Let us see an other case. This time we are in climb, using OP CLB,<BR>which lead to the engagement of THR CLB as A/THR mode. Once again,<BR>we will not follow the bars, pitching the A/C down a little more than<BR>needed.<BR>The speed increases...<BR>FD REVERSION:<BR>OP CLBV/S<BR>THR CLB SPEED<BR>NAV<BR>AUTOFLIGHT MENU<BR>Protections 24/33<BR>NAV<BR>When the aircraft reaches VMO/MMO, the A/THR mode reverts from<BR>THR CLB to SPEED and thrust decreases to recapture the target speed.<BR>Simultaneously, OP CLB mode reverts to V/S on current V/S value.<BR>NOTE: Depending on the A/C configuration, this reversion can occur at<BR>VLE or VFE.<BR>FD REVERSION:<BR>OP CLBV/S<BR>THR CLB SPEED<BR>AUTOFLIGHT MENU<BR>Protections 25/33<BR>As a summary, the flight envelope limit speed protection is<BR>ensured by AP or A/THR (with FD ON, AP OFF) mode reversion<BR>so that:<BR>- At minimum speed, the A/C pitches down or thrust is<BR>added automatically to regain target speed,<BR>- At maximum speed, the A/C pitches up or thrust is<BR>reduced automatically to regain target speed.<BR>AUTOFLIGHT MENU<BR>Protections 26/33<BR>Let’s review some essential mode reversions when you modify<BR>the FCU target altitude during climb or descent.<BR>These mode reversions are designed so as not to modify the<BR>A/C pitch behavior due to the new altitude selection. It leaves it up<BR>to you to decide the further orders you wish to give the FG.<BR>AUTOFLIGHT MENU<BR>Protections 27/33<BR>NAV<BR>Suppose we are in climb (using either OP CLB or CLB) to FL250 as<BR>cleared by ATC. While crossing FL225, ATC requires us to level off at<BR>FL220...<BR>REVERSION TO V/S<BR>ON FCU ALT CHANGE<BR>AUTOFLIGHT MENU<BR>Protections 28/33<BR>NAV<BR>We therefore select the FCU target altitude to FL220. The AP/FD<BR>vertical mode reverts to V/S on the current V/S value.<BR>Notice also that ALT (blue) is not armed.<BR>REVERSION TO V/S<BR>ON FCU ALT CHANGE<BR>AUTOFLIGHT MENU<BR>Protections 29/33<BR>It is then up to the pilot to decide how to regain FL220:<BR>- By dialing the desired V/S target (I.e. down to -1000ft), or,<BR>- By pulling the ALT selector to engage OP DES…<BR>NOTE: You can imagine the same scenario in descent.<BR>NAV<BR>REVERSION TO V/S<BR>ON FCU ALT CHANGE<BR>AUTOFLIGHT MENU<BR>Protections 30/33<BR>We are now capturing the target altitude (ALT* green). The ATC<BR>clears us back up to FL250...<BR>NAV<BR>REVERSION TO V/S<BR>ON FCU ALT CHANGE<BR>AUTOFLIGHT MENU<BR>Protections 31/33<BR>We therefore select the FCU ALT target to FL250.<BR>The AP/FD vertical mode reverts, once again, to V/S, with the current<BR>V/S value.<BR>NAV<BR>REVERSION TO V/S<BR>ON FCU ALT CHANGE<BR>AUTOFLIGHT MENU<BR>Protections 32/33<BR>REVERSION TO V/S<BR>ON FCU ALT CHANGE<BR>It is now up to the pilot to decide how to regain ALT target:<BR>- By pulling the ALT selector to engage OP CLB, or,<BR>- By dialing the desired V/S target (I.e. up to +1500ft)…<BR>NAV<BR>AUTOFLIGHT MENU<BR>Protections 33/33<BR>These are the essential mode reversions linked to FCU<BR>target changes which you may have to do in case of ATC<BR>late clearances.<BR>They ensure no discontinuity in A/C behavior, and<BR>leave you full authority to satisfy these clearances.<BR>NOTE: There are other mode reversions, such as CLB to<BR>OP CLB, or DES to V/S when you select HDG out of NAV,<BR>which follow the same principle.<BR>NEXT<BR>MMoodduullee ccoommpplleetteedd<BR>AUTOFLIGHT MENU Protections 34/33<BR>LLIISSTTOOFFSSUUBBJJEECCTTSS<BR>EXIT<BR>AUDIO GLOSSARY FCOM<BR>RETURN<BR>FFMMGGSSAASSSSIISSTTAANNCCEE<BR>SSPPEEEEDDPPRROOTTEECCTTIIOONNSS((AAPPOONN))<BR>AALLTTTTAARRGGEETTRREEVVEERRSSIIOONNSS<BR>SSPPEEEEDDPPRROOTTEECCTTIIOONNSS((AAPPOOFFFF)) 辛苦了,谢谢 good................ 空客飞行员指南 好资料,学习中。。。 好东西。好好学习一下
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