WebConference-01-RTOLW_FAQ_takeoff.ppt
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Flight Operations Web Conference – 05 May 2009 © AIRBUS S. All rights reserved. Confidential and proprietary document. RTOW charts, Frequently Asked Questions
Flight Operations Web Conference • NEW concept • Flight Operations topic presented during 20 minutes • Questions may be asked in real time • Answers to some selected questions will be given after the presentation (please stay on line after the end of presentation) © AIRBUS S. All rights reserved. Confidential and proprietary document. • This type of Web Conference will be organized on a regular basis
Presented by: Thierry PAYA-ARNAUD Performance Training manager RTOW charts, Frequently Asked Questions
FAQ about takeoff charts - Content © AIRBUS S. All rights reserved. Confidential and proprietary document. • Minimum speeds • Acceleration altitudes • V 1 evolution • Speeds checks • Limitation Codes • Flex corrections • TMAX, TFLEXMAX
© AIRBUS S. All rights reserved. Confidential and proprietary document. FAQ about takeoff charts - Min Speeds VMC, VMU…
© AIRBUS S. All rights reserved. Confidential and proprietary document. FAQ about takeoff charts - Min Speeds What is the meaning of the grey bar ?
FAQ about takeoff charts - Min Speeds What is the meaning of the grey bar ? • A grey bar indicates that a takeoff speed is close to a VMC limitation. This limitation can be : limited by VMCG 4 V 2 © AIRBUS S. All rights reserved. Confidential and proprietary document. 4 V 1 limited by VMCA • This indication is given so that the pilot pays particular attention to the aircraft control at these low speeds.
FAQ about takeoff charts - Min Speeds © AIRBUS S. All rights reserved. Confidential and proprietary document. How come V 1 can be lower than the minimum V 1 given at the bottom of the chart ?
FAQ about takeoff charts - Min Speeds How come V 1 can be lower than the minimum V 1 given at the bottom of the chart ? • Minimum V 1 given at the bottom of the chart is calculated by adding the maximum VMCG on the global set of points (Complete chart) + 4 4 the maximum (V 1 -VEF) (Complete chart) © AIRBUS S. All rights reserved. Confidential and proprietary document. • For a given point, V 1 can be less than this minimum value if (VEF = VMCG) and (V 1 - VEF) is less than max (V 1 - VEF)
© AIRBUS S. All rights reserved. Confidential and proprietary document. FAQ about takeoff charts - Acceleration altitudes
FAQ about takeoff charts – Acceleration altitudes © AIRBUS S. All rights reserved. Confidential and proprietary document. Why are there stars in place of the min and max acceleration altitudes ?
FAQ about takeoff charts – Acceleration altitudes Why are there stars in place of the min and max acceleration altitudes ? © AIRBUS S. All rights reserved. Confidential and proprietary document. • Minimum acceleration altitude is calculated as the MAXIMUM of the ‘min acc. Altitude’ values on the global set of points • Maximum acceleration altitude is calculated as the MINIMUM of the ‘max acc. Altitude’ values on the global set of points • It may then happen that the min acc. altitude is higher than the max acc. altitude : in this case, stars are displayed in the chart and the min and max acc. altitude values must be read in a specific chart.
© AIRBUS S. All rights reserved. Confidential and proprietary document. FAQ about takeoff charts – Acceleration altitudes
© AIRBUS S. All rights reserved. Confidential and proprietary document. FAQ about takeoff charts - V 1 evolution
FAQ about takeoff charts - V 1 evolution © AIRBUS S. All rights reserved. Confidential and proprietary document. How come V 1 can increase while the weight decreases ?
FAQ about takeoff charts - V 1 evolution How come V 1 can increase while the weight decreases ? • In this example, we are Obstacle and Brake energy limited. • To reduce TOD, it may be interesting to increase V 1 but V 1 is limited by Max Brake Energy speed © AIRBUS S. All rights reserved. Confidential and proprietary document. • The brake energy limitation depends on weight and the thrust • When OAT increases, the Weight decreases and the thrust decreases • When OAT increases, Max V 1 limited by Max brake energy speed increases.
© AIRBUS S. All rights reserved. Confidential and proprietary document. FAQ about takeoff charts – Speeds checks
FAQ about takeoff charts – Speeds checks © AIRBUS S. All rights reserved. Confidential and proprietary document. When applying influence corrections, do I have to check the speeds against the minimum values given at the bottom of the chart ?
FAQ about takeoff charts – Speeds checks When applying influence corrections, do I have to check the speeds against the minimum values given at the bottom of the chart ? • Yes, when 4 More than one correction is applied © AIRBUS S. All rights reserved. Confidential and proprietary document. • If no correction or only one correction is applied, the speeds are OK. No speed Check against ‘min speeds’.
© AIRBUS S. All rights reserved. Confidential and proprietary document. FAQ about takeoff charts – Limitation Codes V 1 V 2
FAQ about takeoff charts – Limitation Codes © AIRBUS S. All rights reserved. Confidential and proprietary document. On a weight chart, can I interpolate between 2 weights with different limitation codes ?
FAQ about takeoff charts – Limitation Codes On a weight chart, can I interpolate between 2 weights with different limitation codes ? • Yes, because automatic temperature chart used to build the weight chart is accurate enough (slight trend below Tref, step of 2°C above Tref) © AIRBUS S. All rights reserved. Confidential and proprietary document. 4 the
© AIRBUS S. All rights reserved. Confidential and proprietary document. FAQ about takeoff charts – Flex corrections
FAQ about takeoff charts – Flex corrections © AIRBUS S. All rights reserved. Confidential and proprietary document. When applying corrections on TFlex for QNH or bleeds, why isn’t there a correction on the speeds ?
FAQ about takeoff charts – Flex corrections When applying corrections on TFlex for QNH or bleeds, why isn’t there a correction on the speeds ? • The speeds are directly linked to the takeoff weight for a given runway length and braking capability of the aircraft • In case of QNH or bleed correction, the only affected item © AIRBUS S. All rights reserved. Confidential and proprietary document. is the engine thrust
FAQ about takeoff charts – Flex corrections When applying corrections on TFlex for QNH or bleeds, why isn’t there a correction on the speeds ? Weight Thrust Flat rated Thrust Actual TOW Needed Thrust Bleeds correction © AIRBUS S. All rights reserved. Confidential and proprietary document. EGT Limit ΔTFlex Temp correction Flex Temp Bleeds ON full Thrust OAT
FAQ about takeoff charts – Flex corrections When applying corrections on TFlex for QNH or bleeds, why isn’t there a correction on the speeds ? • The flex temperature correction is calculated so that the thrust after TFlex and Bleeds correction is equal to the thrust needed without bleeds. • As the aircraft braking capability is not degraded, the © AIRBUS S. All rights reserved. Confidential and proprietary document. speeds don’t need to be modified.
FAQ about takeoff charts – TMAX, TFLEXMAX © AIRBUS S. All rights reserved. Confidential and proprietary document. Why do I have temperatures above the TMAX indicated on the bottom of the chart ?
FAQ about takeoff charts – TMAX, TFLEXMAX • TMax is the MAX • © AIRBUS S. All rights reserved. Confidential and proprietary document. • certified OAT For dispatch The RTOW chart is used for MTOW determination and for FLEX computation The range of temperature covers OAT up to TMax AND temperature Above Tmax, Up to Tflex. MAX Why do I have temperatures above the TMAX indicated on the bottom of the chart ? Last value of OAT for Dispatch Temperature for Flex only 54
FAQ about takeoff charts – TMAX, TFLEXMAX © AIRBUS S. All rights reserved. Confidential and proprietary document. I received new charts for a new aircraft. Why is the max temperature displayed on the chart much higher than before
FAQ about takeoff charts – TMAX, TFLEXMAX I received new charts for a new aircraft. Why is the max temperature displayed on the chart much higher than before © AIRBUS S. All rights reserved. Confidential and proprietary document. • To improve customers operations, The maximum Thrust reduction has been increased • This is available as ‘Extended Flex’ option • On this example, the TFlex. Max is increased from ISA + 43°C to ISA + 72°C • The new charts computed for aircraft equipped with Extended flex option will provide temperature much higher than before
© AIRBUS S. All rights reserved. Confidential and proprietary document. Questions?
Questions • Question: For the same conditions, if there is the same TOW for CONF 2 and CONF 3, which one is more favorable? © AIRBUS S. All rights reserved. Confidential and proprietary document. • Answer: According to FCOM, use the configuration that gives the highest flex. If both of them provide the same level of flex thrust or if you cannot flex, use the one with the highest flaps setting. This may change in specific conditions. Please refer to FCOM 2. 02. 14. P 2.
Questions • Question: I understand that when the code changes between 2 boxes, one can interpolate between the take off weights. But can we also interpolate for the speeds, which at times change dramatically? © AIRBUS S. All rights reserved. Confidential and proprietary document. • Answer: Yes. Interpolation shall be done for all parameters (weight and speeds).
Questions • Question: © AIRBUS S. All rights reserved. Confidential and proprietary document. Sometimes, ATC requires the aircraft to enter the runway using alternate runway entrance. The take off runway distance available is then reduced. And the crew needs to update the take off speeds accordingly. How can we handle this? • Answer: There is no simple way to handle that with paper RTOW charts. A specific chart may be used for a very often used taxiway, but that increases the number of charts. The use of LPC (software on board) allows this type of computation.
Questions • Question: I've checked the landing distance performance of our A 320 -211 using the FOVE landing module. The difference between normal landings distance vs. abnormal, especially on contaminated runways seem to be negligible. © AIRBUS S. All rights reserved. Confidential and proprietary document. • Answer: The impact of failure during the flight depends on the failure case. This impact is given in the QRH with failure coefficients. Some of them are low (1. 1 or 1. 2) because the failure only requires higher speed and has no effect on braking capability of the aircraft. In any case, keep in mind that the distances given by the QRH or the LPC are reference landing distances and that the crew shall retain a runway with sufficient margins.
Questions • Question: Similar for takeoff, how do you calculate MIN ACC ALT and MAX ACC ALT for go-around with Engine Out? © AIRBUS S. All rights reserved. Confidential and proprietary document. • Answer: There is no MIN ACC ALT or MAX ACC ALT definition for go-around. What has to be checked in case of a go-around is that the aircraft remains above the plane (i. e. surface) defined by the missed approach gradient. You can refer to the presentation held in Paris Conference this year for more details on go-around procedure check.
Questions • Question: Why has the Bleed corrections to Flex increased a lot recently? © AIRBUS S. All rights reserved. Confidential and proprietary document. • Answer: The Anti-ice corrections increase is linked to an Octopus change. You can refer to PEP 4. 4 reasons for change. The principle of anti-ice corrections on takeoff charts have been modified: the reduced temperatures list (below 10°C OAT) is used only to determine weight and speed corrections, the complete temperatures list is used for flex temp correction. The same principle is used in the FCOM. As a consequence, Flex corrections for anti-ice may have been updated in the FCOM and takeoff charts corrections must be recomputed.
Questions • Question: With Tmax. Flex of ISA+75, for sure you would go below 25% max legal thrust reduction? Can you explain? © AIRBUS S. All rights reserved. Confidential and proprietary document. • Answer: Airbus re discussed this 25% max reduction and obtained a new certification from authorities for this modification. Keep in mind that it was already possible for other manufacturer to go beyond 25% using Flex on Derate.
Questions • Question: Can you please discuss Airbus philosophy for operations with the A 320 on runways with a width less than 45 meters? © AIRBUS S. All rights reserved. Confidential and proprietary document. • Answer: Operating on a runway with a width lower than 45 m implies an increase in VMCG to be able to control the aircraft inside the limits of the runway as described in the regulation. This VMCG increment is automatically taken into by the software provided the runway width has been correctly entered.
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WebConference-01-RTOLW_FAQ_takeoff.ppt