Presentation on theme: "Flight Operations Web Conference – 05 May 2009"— Presentation transcript:
1Flight Operations Web Conference – 05 May 2009 RTOW charts, Frequently Asked Questions
2Flight Operations Web Conference NEW conceptFlight Operations topic presented during 20 minutesQuestions may be asked in real timeAnswers to some selected questions will be given after the presentation (please stay on line after the end of presentation)This type of Web Conference will be organized on a regular basis
6FAQ about takeoff charts - Min Speeds What is the meaning of the grey bar ?
7FAQ 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 :V1 limited by VMCGV2 limited by VMCAThis indication is given so that the pilot pays particular attention to the aircraft control at these low speeds.
8FAQ about takeoff charts - Min Speeds How come V1 can be lower than the minimum V1 given at the bottom of the chart ?
9FAQ about takeoff charts - Min Speeds How come V1 can be lower than the minimum V1 given at the bottom of the chart ?Minimum V1 given at the bottom of the chart is calculated by addingthe maximum VMCG on the global set of points (Complete chart) +the maximum (V1-VEF) (Complete chart)For a given point, V1 can be less than this minimum value if (VEF = VMCG) and (V1- VEF) is less than max (V1 - VEF)
10FAQ about takeoff charts - Acceleration altitudes
11FAQ about takeoff charts – Acceleration altitudes Why are there stars in place of the min and max acceleration altitudes ?
12FAQ about takeoff charts – Acceleration altitudes Why are there stars in place of the min and max acceleration altitudes ?Minimum acceleration altitude is calculated as the MAXIMUM of the ‘min acc. Altitude’ values on the global set of pointsMaximum acceleration altitude is calculated as the MINIMUM of the ‘max acc. Altitude’ values on the global set of pointsIt 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.
13FAQ about takeoff charts – Acceleration altitudes
15FAQ about takeoff charts - V1 evolution How come V1 can increasewhile the weight decreases ?
16FAQ about takeoff charts - V1 evolution How come V1 can increasewhile the weight decreases ?In this example, we are Obstacle and Brake energy limited.To reduce TOD, it may be interesting to increase V1 but V1 is limited by Max Brake Energy speedThe brake energy limitation depends on weight and the thrustWhen OAT increases, the Weight decreases and the thrust decreasesWhen OAT increases, Max V1 limited by Max brake energy speed increases.
18FAQ about takeoff charts – Speeds checks When applying influence corrections, do I have to check the speeds against the minimum values given at the bottomof the chart ?
19FAQ about takeoff charts – Speeds checks When applying influence corrections, do I have to check the speeds against the minimum values given at the bottomof the chart ?Yes, whenMore than one correction is appliedIf no correction or only one correction is applied, the speeds are OK. No speed Check against ‘min speeds’.
20FAQ about takeoff charts – Limitation Codes V1V2
21FAQ about takeoff charts – Limitation Codes On a weight chart, can I interpolate between 2 weights with different limitation codes ?
22FAQ about takeoff charts – Limitation Codes On a weight chart, can I interpolate between 2 weights with different limitation codes ?Yes, becausethe automatic temperature chart used to build the weight chart is accurate enough (slight trend below Tref, step of 2°C above Tref)
24FAQ about takeoff charts – Flex corrections When applying corrections on TFlex for QNH or bleeds, why isn’t there a correction on the speeds ?
25FAQ 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 aircraftIn case of QNH or bleed correction, the only affected item is the engine thrust
26FAQ about takeoff charts – Flex corrections When applying corrections on TFlex for QNH or bleeds, why isn’t there a correction on the speeds ?WeightThrustFlat rated ThrustBleeds correctionActual TOWNeededThrustEGT LimitΔTFlex TempcorrectionFlex TempBleeds ONFlex Tempfull ThrustOAT
27FAQ 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 speeds don’t need to be modified.
28FAQ about takeoff charts – TMAX, TFLEXMAX Why do I have temperatures above the TMAX indicated on the bottom of the chart ?
29FAQ about takeoff charts – TMAX, TFLEXMAX TMax is the MAX certified OAT For dispatchThe RTOW chart is used for MTOW determination and for FLEX computationThe range of temperature covers OAT up to TMax AND temperature Above Tmax, Up to TflexMAXWhy do I have temperatures above the TMAX indicated on the bottom of the chart ?Last value of OAT for DispatchTemperature for Flex only54
30FAQ 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
31FAQ about takeoff charts – TMAX, TFLEXMAX To improve customers operations, The maximum Thrust reduction has been increasedThis is available as ‘Extended Flex’ optionOn this example, the TFlexMax is increased from ISA + 43°C to ISA + 72°CThe new charts computed for aircraft equipped with Extended flex option will provide temperature much higher than beforeI received new charts for a new aircraft .Why is the max temperature displayed on the chart much higher than before
33QuestionsQuestion: For the same conditions, if there is the same TOW for CONF 2 and CONF 3, which one is more favorable?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 P2.
34QuestionsQuestion: 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?Answer: Yes. Interpolation shall be done for all parameters (weight and speeds).
35QuestionsQuestion: 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.
36QuestionsQuestion: I've checked the landing distance performance of our A using the FOVE landing module. The difference between normal landings distance vs. abnormal, especially on contaminated runways seem to be negligible.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.
37QuestionsQuestion: Similar for takeoff, how do you calculate MIN ACC ALT and MAX ACC ALT for go-around with Engine Out?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.
38QuestionsQuestion: Why has the Bleed corrections to Flex increased a lot recently?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.
39QuestionsQuestion: With TmaxFlex of ISA+75, for sure you would go below 25% max legal thrust reduction? Can you explain?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.
40QuestionsQuestion: Can you please discuss Airbus philosophy for operations with the A320 on runways with a width less than 45 meters?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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