PDA

View Full Version : A320 Engine Failure After V1


Boyington
2nd Jun 2018, 16:08
In the FCTM there is a Note which states as follows:
" If the decision has been taken to delay the acceleration, the flight crew must not delay the engine out maximum acceleration altitude. ( The engine out maximum acceleration altitude corresponds to the maximum altitude that can be achieved with one engine out and the other engine operating at takeoff thrust for a maximum of 10 minutes).

My query is this: Isn't the time limit 0f 10 minutes only for TOGA thrust? Why is it mentioned as "takeoff' thrust as it will then include Flex thrust also?

RUMBEAR
2nd Jun 2018, 16:35
TOGA and FLEX are both take off thrust settings! Need to set MCT to remove the time limitation.

booze
2nd Jun 2018, 16:37
I think it is taking into account (as worst case scenario) considering TOGA at some point.

pineteam
2nd Jun 2018, 16:59
Yes it includes Flex also. Flex can be at best maximum of 25% less power than TOGA and some other days, pretty close to TOGA power: eg: Heavy aircraft on a hot day.

vilas
2nd Jun 2018, 17:26
The limitation is on takeoff thrust so it is applicable to Flex also. Now with improved FADEC the flex reduction can be up to 40%. Most airlines are now operating to that. The question you should ask is why there is Max altitude when it is matter of time ten minutes.

RAT 5
2nd Jun 2018, 17:52
The question you should ask is why there is Max altitude when it is matter of time ten minutes.

Indeed. It would be difficult to apply 2 limitations to the same thing. Surely, from an engine/performance/paid for approval point of view time must be the governing factor.

TOGA and FLEX are both take off thrust settings! Need to set MCT to remove the time limitation.

What if MCT is higher than the reduced thrust/flex setting? Does that make sense, then? Not being an AB man.

booze
2nd Jun 2018, 21:20
Just did two calculations under the same conditions and same aircraft. The one with FLEX gave me 2789' maxEOaccALT, the one with TOGA 3253'. Those are the altitudes one can reach under the prescribed conditions having FLEX or TOGA selected respectively. The first will be rather conservative when considering then selecting TOGA at some point during takeoff.

vilas
3rd Jun 2018, 04:24
The limitation on takeoff thrust is ten minutes. However the RTOW chart considers the altitudes that will be reached for the whole chart in ten minutes and the minimum of those is displayed as the MAXIMUM ACC ALITUDE. As long as you accelerate before or at that ten minutes limitation will not be infringed. More conservative.

pineteam
3rd Jun 2018, 07:37
The limitation is on takeoff thrust so it is applicable to Flex also. Now with improved FADEC the flex reduction can be up to 40%.

I did not know that. :}Thank you Vilas. You are always ahead of the game in term of knowledge. What’s your secret?

Capt Scribble
3rd Jun 2018, 08:13
I see that Airbus ‘Smart Cockpit’ says that the Fadec can produce a 40% thrust reduction, but I thought that the regulations set the limit at 25% of T/O thrust.

vilas
3rd Jun 2018, 13:03
CS
The regulations reads 25% but subject to some MOD it permits up to 40% reduction in actual operation. All RTOW charts giving Flex of 70 odd are at 40% reduction.

Boyington
3rd Jun 2018, 13:16
The limitation on takeoff thrust is ten minutes. However the RTOW chart considers the altitudes that will be reached for the whole chart in ten minutes and the minimum of those is displayed as the MAXIMUM ACC ALITUDE. As long as you accelerate before or at that ten minutes limitation will not be infringed. More conservative.

Have seen a chart where the ACC ALTITUDE is mentioned in the RTOW charts as around 1300' AGL. Does it mean that the aircraft will reach only reach 1300'AGL in single engine with the operating engine at T/O thrust?

vilas
3rd Jun 2018, 13:27
From Airbus web conference.
• To improve customers operations, The maximum Thrust reduction has been increased
• This is available as ‘Extended Flex’ option
• On this example, the TFlexMax 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

vilas
3rd Jun 2018, 15:05
Boyington
I have seen one airline RTOW chart where the difference between minimum and maximum acceleration altitude was few feet. Obviously there was something wrong with it. Check on your flysmart and see.

Boyington
5th Jun 2018, 14:40
Maximum Acceleration Altitude corresponds to the minimum of the maximum acceleration heights of all the points of the chart. What does all the points on the chart mean as one chart is meant for one Runway length?

vilas
5th Jun 2018, 17:49
RW length is same but each box of the chart has different temperature and weight. So the height reached in ten minutes is different. The minimum of these is displayed at the bottom as the maximum altitude.

MD83FO
6th Jun 2018, 17:15
while we're in the subject, I'd appreciate some guidance because I didn't get a proper debriefing in the sim,
EGT overlimit after 100kts (called by PM) after V1 very Heavy Vibration no ECAM and no thrust asymmetry, i try to connect autopilot but its not available, the vibration is overwhelming.
what would be the most tidy sequence to manage this situation in the sim environment ?
thank you!

vilas
6th Jun 2018, 18:41
MD83FO
Above 80 kts for EGT exceedence in phase 4 the warning is inhibited there is no requirement to reject takeoff just continue. After airborne depending on the degree of exceedence ECAM procedure will appear. Carry out ECAM. If no ECAM but you get engine vibration again only for engine vibration engine shutdown is not required. Apply the QRH procedure.