AF 777 wrong weight inputs, off by 100 tonnes?
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This one was AF...
Airbus A340: July 2004
Location: Paris, France
History of the flight:
On 14 July 2004, an Airbus A340-300 aircraft, registered F-GLZR, was being prepared for a passenger service, departing from Charles de Gaulle Airport, France. In preparation for the flight, the crew received an expected TOW of 268,600 kg, which was close to the aircraft’s maximum take-off weight (MTOW) of 271,000 kg. The TOW, rounded up to 270,000 kg, was used to submit a take-off data calculation request via the ACARS. The resultant take-off performance parameters were verified by the crew.
Shortly after, the crew were advised that the TOW was 5,200 kg less than that previously provided, resulting in a TOW of 264,800 kg. As the change in weight was greater than 5,000 kg, the crew were required to submit a new ACARS request. When entering the revised TOW into the ACARS via the FMGS interface, a weight of 165,000 kg was inadvertently entered. This weight was close to the ZFW of 164,480 kg. The resultant V speeds and FLEX temperature were then entered into the FMGS. The captain confirmed the parameters; however, he did not detect the error as he read the MTOW from the ACARS printout instead of the TOW.
During the takeoff, the pilot flying reported the aircraft feeling heavy and noticed that the V2 speed was slower than the VLS speed (the lowest selectable speed, which provides an appropriate margin above the stall speed); take-off/go-around thrust was not applied. The aircraft sustained a tailstrike, with the fuselage remaining in contact with the runway for a distance of about 100 metres.
Contributing factors:
The following factors were identified throughout the subsequent investigation:
• A weight similar to the ZFW was inadvertently entered into the ACARS instead of the actual TOW, resulting in low V speeds.
Take-off performance data:
Data Required Used
TOW 265,000 kg 165,000 kg
V1 143 kts 129 kts
VR 153 kts 131 kts
V2 161 kts 137 kts
• The FMGS would accept unrealistic low V speeds without challenge.
• The FMGS did not compare the V2 and VLS speeds, despite the fact that both values were known before takeoff.
The following information is based on a translation of the Bureau d’Enquétes et d’Analyses pour la sécurité de l’aviation civile’s (BEA) investigation report. Some information may have been omitted or incorrectly interpreted through the translation process.
•The presentation of the parameter values on the ACARS printout may have led to some confusion in reading between the TOW and ZFW.
•The take-off briefing procedures did not require a comparison between the TOW and speed characteristics.
Airbus A340: July 2004
Location: Paris, France
History of the flight:
On 14 July 2004, an Airbus A340-300 aircraft, registered F-GLZR, was being prepared for a passenger service, departing from Charles de Gaulle Airport, France. In preparation for the flight, the crew received an expected TOW of 268,600 kg, which was close to the aircraft’s maximum take-off weight (MTOW) of 271,000 kg. The TOW, rounded up to 270,000 kg, was used to submit a take-off data calculation request via the ACARS. The resultant take-off performance parameters were verified by the crew.
Shortly after, the crew were advised that the TOW was 5,200 kg less than that previously provided, resulting in a TOW of 264,800 kg. As the change in weight was greater than 5,000 kg, the crew were required to submit a new ACARS request. When entering the revised TOW into the ACARS via the FMGS interface, a weight of 165,000 kg was inadvertently entered. This weight was close to the ZFW of 164,480 kg. The resultant V speeds and FLEX temperature were then entered into the FMGS. The captain confirmed the parameters; however, he did not detect the error as he read the MTOW from the ACARS printout instead of the TOW.
During the takeoff, the pilot flying reported the aircraft feeling heavy and noticed that the V2 speed was slower than the VLS speed (the lowest selectable speed, which provides an appropriate margin above the stall speed); take-off/go-around thrust was not applied. The aircraft sustained a tailstrike, with the fuselage remaining in contact with the runway for a distance of about 100 metres.
Contributing factors:
The following factors were identified throughout the subsequent investigation:
• A weight similar to the ZFW was inadvertently entered into the ACARS instead of the actual TOW, resulting in low V speeds.
Take-off performance data:
Data Required Used
TOW 265,000 kg 165,000 kg
V1 143 kts 129 kts
VR 153 kts 131 kts
V2 161 kts 137 kts
• The FMGS would accept unrealistic low V speeds without challenge.
• The FMGS did not compare the V2 and VLS speeds, despite the fact that both values were known before takeoff.
The following information is based on a translation of the Bureau d’Enquétes et d’Analyses pour la sécurité de l’aviation civile’s (BEA) investigation report. Some information may have been omitted or incorrectly interpreted through the translation process.
•The presentation of the parameter values on the ACARS printout may have led to some confusion in reading between the TOW and ZFW.
•The take-off briefing procedures did not require a comparison between the TOW and speed characteristics.
Last edited by JammedStab; 21st Jun 2015 at 16:56.
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Stick one of these on the windscreen. completely standalone accelerometer, and just have a good idea of your plane's ideal 0-60. I'd guess you're usually around 10 seconds, so if it takes 14, either the handbrake is on, or you're down on power.
Should work on all types, the only real issue I can see is the lack of a cigarette lighter socket on the flightdeck
Should work on all types, the only real issue I can see is the lack of a cigarette lighter socket on the flightdeck
Mistrust in Management
latetonite
Evening to you latetonite.
About 50 to 55 seconds if my memory is correct.
Of course a 4 engine aircraft is somewhat less sprightly on the take off roll than a modern twin due to the need to only meet a 25% power loss at V1.
So I agree with your comment about vigilance.
Kind regards
Exeng
About 50 to 55 seconds if my memory is correct.
Of course a 4 engine aircraft is somewhat less sprightly on the take off roll than a modern twin due to the need to only meet a 25% power loss at V1.
So I agree with your comment about vigilance.
Kind regards
Exeng
...and just have a good idea of your plane's ideal 0-60
A lighter airplane has a lower Vrotate, but also a much reduced rejected-takeoff stopping distance due to both the lower Vrotate and the faster deceleration. In combination this all has a big effect on the required takeoff acceleration.
Consequently, even when weight planning is completely correct the aircraft may seem to have an extremely leisurely take-off acceleration. So realising that the acceleration is even less because the aircraft is too heavy is not necessarily something one can judge easily.
[N.B Speaking very much as a theoretician - not a commercial pilot.]
Last edited by Dont Hang Up; 30th Jun 2015 at 11:52.
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Just FYI the 747-8F has a Weight and Balance system. It gives real time GW, MAC CG, ZFW and ZFW CG. The WBS uses sensors mounted on the Landing Gear.
GW and MAC CG information goes to the FMC and IDS.
This info can also be read on the Remote dedicated display unit (RDDU) that lives on the Main Deck although ZFW and ZFWCG can only be read on the W & B Computer Display in the MEC.
GW and MAC CG information goes to the FMC and IDS.
This info can also be read on the Remote dedicated display unit (RDDU) that lives on the Main Deck although ZFW and ZFWCG can only be read on the W & B Computer Display in the MEC.
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Again, the debate has become fixated on weight. With a computer performance programme, typically fifteen or so items of data have to be entered, of which weight is just one. A single mistaken or transposed digit will make nonsense of the end result. The only fatal instance that I'm aware of was the Halifax 747 where their mistake was to make the calculation based on the previous departure airfield to which the laptop had defaulted. As with the Emirates tailscrape, fatigue played a major part; the fatal flight was the return sector for a second Atlantic crossing in the same duty period.
I'm pretty sure from memory that they said fatigue played no part in the Emirates accident in the final report. I stand to be corrected though as my memory sometimes lets me down .
