A320/A321 Flight Crew Techniques Manual - ZFW-ZFWCG Entry Errors PDF

AIRCRAFT SYSTEMS FLIGHT MANAGEMENT A320/A321 FLIGHT CREW USE OF FMS TECHNIQUES MANUAL...

AIRCRAFT SYSTEMS FLIGHT MANAGEMENT A320/A321 FLIGHT CREW USE OF FMS TECHNIQUES MANUAL ZFW - ZFWCG ENTRY ERRORS Ident.: AS-FM-10-A-00019558.0002001 / 20 MAR 17 Criteria: J3283, J3448, P8572, SA 2 !""#$%&'#( )*+ A321ceo, A320neo, A321neo GENERAL The aircraft Gross Weight (GW) and Centre of Gravity (CG) are computed independently by the FM and FAC: ‐ GW and CG values FM computed are used for: FM predictions and speeds ECAM (GW) MCDU (GW and CG) Computation of characteristic speeds (VLS, F, S, GD) for display on PFD ‐ GW and CG values FAC computed are used for: Flight control laws A ZFW or ZFWCG entry error in MCDU INIT B page induces calculation errors that are to be highlighted. CFG A320/A321 FLEET AS-FM-10 P 4/12 FCTM ← A to B → 28 NOV 23  AIRCRAFT SYSTEMS FLIGHT MANAGEMENT A320/A321 FLIGHT CREW USE OF FMS TECHNIQUES MANUAL !"#$%&' ()*+,*-.*(*...-/001&...-..- 2 3. ,(4 -5 678%#789' )( !""#$%&'#( )*+ A320ceo GENERAL The aircraft Gross Weight (GW) and Centre of Gravity (CG) are computed independently by the FM and FAC: ‐ GW and CG values FM computed are used for: FM predictions and speeds ECAM (GW) MCDU (GW and CG). ‐ GW and CG values FAC computed are used for: Flight control laws Computation of characteristic speeds (VLS, F, S, GD) for display on PFD. A ZFW or ZFWCG entry error in MCDU INIT B page induces calculation errors that are to be highlighted. Ident.: AS-FM-10-A-00019559.0002001 / 11 MAY 21 Criteria: J3283, J3438, P8572, SA 3 !""#$%&'#( )*+ A321ceo, A320neo, A321neo TECHNICAL BACKGROUND The GW and CG computation is as follows: 1. The flight crew enters the ZFW and ZFWCG in the INIT B page. 2. The FMGC computes the GW and CG from: ‐ The ZFW, ZFWCG inserted in the INIT B page ‐ The fuel quantities from the FQI ‐ The Fuel Flow from the FADEC. 3. This current GW and/or CG is used: ‐ For FM predictions and speeds ‐ For ECAM display (GW only) ‐ For MCDU (GW and CG) ‐ By FAC for characteristic speed computation for PFD. 4. The FAC computes its own GW and CG from aerodynamic data. 5. GW and CG FAC computed are used for minor adjustments on the flight control laws. CFG A320/A321 FLEET AS-FM-10 P 5/12 FCTM ←B→ 28 NOV 23  AIRCRAFT SYSTEMS FLIGHT MANAGEMENT A320/A321 FLIGHT CREW USE OF FMS TECHNIQUES MANUAL GW and CG Computation and Use Note: ‐ On ground, FAC uses the GW FM computed. ‐ In flight, at low altitude (below 14 625 ft), low speed (below 250 kt) and flight parameters stabilized, GW FAC computed comes from aerodynamic data. If these conditions are not met, GW FAC computed equates to the last memorized GW minus fuel used. ‐ If the GW FM computed and FAC computed differs from a given threshold, a CHECK GW message appears on the MCDU scratchpad. CFG A320/A321 FLEET AS-FM-10 P 6/12 FCTM ←B→ 28 NOV 23  AIRCRAFT SYSTEMS FLIGHT MANAGEMENT A320/A321 FLIGHT CREW USE OF FMS TECHNIQUES MANUAL !"#$%&' ()*+,*-.*(*...-/00/&...-..- 1 -- ,(2 3- 456%#567' )( !""#$%&'#( )*+ A320ceo TECHNICAL BACKGROUND The GW and CG computation is as follows: 1. The flight crew enters the ZFW and ZFWCG in the INIT B page. 2. The FMGC computes the GW and CG from: ‐ The ZFW, ZFWCG inserted in the INIT B page ‐ The fuel quantities from the FQI ‐ The Fuel Flow from the FADEC. 3. This current GW and/or CG is used for: ‐ FM predictions and speeds ‐ ECAM (GW only) ‐ MCDU (GW and CG). 4. The FAC computes its own GW and CG from aerodynamic data. 5. GW and CG FAC computed are used for: ‐ Minor adjustments on the flight control laws ‐ Characteristic speeds (VLS, F, S, Green dot) display on PFD. CFG A320/A321 FLEET AS-FM-10 P 7/12 FCTM ←B→ 28 NOV 23  AIRCRAFT SYSTEMS FLIGHT MANAGEMENT A320/A321 FLIGHT CREW USE OF FMS TECHNIQUES MANUAL GW and CG Computation and Use Note: ‐ On ground, FAC uses the GW FM computed. ‐ In flight, at low altitude (below 14 625 ft), low speed (below 250 kt) and flight parameters stabilized, GW FAC computed comes from aerodynamic data. If these conditions are not met, GW FAC computed equates to the last memorized GW minus fuel used. ‐ If the GW FM computed and FAC computed differs from a given threshold, a CHECK GW message appears on the MCDU scratchpad. CFG A320/A321 FLEET AS-FM-10 P 8/12 FCTM ←B→ 28 NOV 23  AIRCRAFT SYSTEMS FLIGHT MANAGEMENT A320/A321 FLIGHT CREW USE OF FMS TECHNIQUES MANUAL Ident.: AS-FM-10-A-00019560.0002001 / 20 MAR 17 Criteria: J3283, J3438, P8572, SA 4 !""#$%&'#( )*+ A321ceo, A320neo, A321neo ZFW ENTRY ERROR AND OPERATIONAL CONSEQUENCES If the pilot enters erroneous ZFW on MCDU INIT B page, this will affect as follows: ‐ GW and, to a lesser degree, CG, computed by FM are erroneous. This induces the following consequences: The FM predictions and speeds are erroneous Incorrect GW and CG on MCDU FUEL PRED page Incorrect GW displayed on ECAM Characteristic speeds on PFD are erroneous SRS mode guidance is affected if computed VLS is above V2 as inserted in the MCDU PERF TAKE-OFF page. ‐ GW FAC computed, which is based on GW FM computed on ground, will be updated only once airborne through a specific slow calculation using AOA information. Note: 1. In flight, if the FM and FAC GW differ from a given threshold, a "CHECK GW" message is triggered on the MCDU. 2. Valpha prot, Vaalpha max, Vsw are not affected since based on aerodynamic data. ERRONEOUS FUEL ON BOARD ENTRY As long as the engines are not started, the FM GW is erroneous and above-mentioned consequences apply. Once the engines are started, the fuel figures are updated and downstream data update accordingly. It should be noted however, that the FOB on ECAM is correct since it is provided from FQI data. CFG A320/A321 FLEET AS-FM-10 P 9/12 FCTM ←B→ 28 NOV 23  AIRCRAFT SYSTEMS FLIGHT MANAGEMENT A320/A321 FLIGHT CREW USE OF FMS TECHNIQUES MANUAL !"#$%&' ()*+,*-.*(*...-/01.&...-..- 2 3. ,(4 -5 678%#789' )( !""#$%&'#( )*+ A320ceo ZFW ENTRY ERROR AND OPERATIONAL CONSEQUENCES If the pilot enters erroneous ZFW on MCDU INIT B page, this will affect as follows: ‐ GW and, to a lesser degree, CG, computed by FM are erroneous. This induces the following consequences: The FM predictions and speeds are erroneous Incorrect GW and CG on MCDU FUEL PRED page Incorrect GW displayed on ECAM ‐ FAC GW, which is based on FM GW on ground, will be updated only once airborne through a specific slow calculation using AOA information. Consequently, Characteristic speeds on PFD at take-off are erroneous, but they are correct in flight SRS mode guidance is affected if computed VLS is above V2 as inserted in the MCDU PERF TAKE-OFF page. Note: 1. In flight, if the FM and FAC GW differ from a given threshold, a "CHECK GW" message is triggered on the MCDU. 2. Valpha prot, Valpha max, Vsw are not affected since based on aerodynamic data. ERRONEOUS FUEL ON BOARD ENTRY As long as the engines are not started, the FM GW is erroneous and above-mentioned consequences apply. Once the engines are started, the fuel figures are updated and downstream data update accordingly. It should be noted however, that the FOB on ECAM is correct since it is provided from FQI data. Ident.: AS-FM-10-A-00019561.0002001 / 20 MAR 17 Criteria: J3283, J3438, P8572, SA 5 !""#$%&'#( )*+ A321ceo, A320neo, A321neo OPERATIONAL RECOMMENDATIONS ZFW entries should be cross-checked by both crewmembers to avoid entry error. If the "CHECK GW" amber warning is displayed on the MCDU, a discrepancy exists between the FM computed GW and the FAC computed GW. The crew will compare the Load and Trim Sheet (LTS) figures with the FM GW and fuel used: ‐ If an obvious entry error is detected, FM GW will be updated on the MCDU FUEL PRED page. ‐ If FM and LTS GW are in accordance and appear to be correct, the FAC computed GW should be suspected (AOA sensor problem). ‐ If FM and LTS GW are in accordance but LTS GW is suspected, characteristic speeds should be extracted from QRH. CFG A320/A321 FLEET AS-FM-10 P 10/12 FCTM ←B→ 28 NOV 23  AIRCRAFT SYSTEMS FLIGHT MANAGEMENT A320/A321 FLIGHT CREW USE OF FMS TECHNIQUES MANUAL !"#$%&' ()*+,*-.*(*...-/01-&...-..- 2 3. ,(4 -5 678%#789' )( !""#$%&'#( )*+ A320ceo OPERATIONAL RECOMMENDATIONS ZFW entries should be cross-checked by both crewmembers to avoid entry error. If the "CHECK GW" amber warning is displayed on the MCDU, a significant discrepancy exists between the FM computed GW and the FAC computed GW. The crew will compare the Load and Trim Sheet (LTS) figures with the FM GW and fuel used: ‐ If an obvious entry error is detected, FM GW will be updated on the MCDU FUEL PRED page. ‐ If FM and LTS GW are in accordance and appear to be correct, the FAC computed GW should be suspected (AOA sensor problem). Consequently, characteristic speeds on PFD are erroneous and should be disregarded. Characteristic speeds should be extracted from QRH. ‐ If FM and LTS GW are in accordance but LTS GW is suspected, FAC and QRH characteristic speeds should be compared (to validate FAC outputs) and the most appropriate applied. CFG A320/A321 FLEET AS-FM-10 P 11/12 FCTM ←B 28 NOV 23