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  • Evan
    replied
    Originally posted by mfeldt View Post
    What I'm prepared to find myself in is an airplane wreck at the bottom of the Atlantic, even more so if the reason has to do with economic risk management that failed.
    I think this concern needs to be fully vetted, and the go-with-the-flow attitude I've been getting from pilots here is alarming. If it is a red herring, than we need to reach that conclusion by proving it as such. Eight minutes of route reserve less than halfway through an overfueled, underweight flight?

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  • mfeldt
    replied
    Originally posted by MCM View Post

    What you are now talking about is commercial consistency - the fact that you might not make destination on a number of occasions. That is part of the aviation risk management system, and it is very much necessary to keep operations going. If you don't like the idea that you might not be able to make your destination, then don't fly longhaul.
    I have very little against the idea of occasionally not making my destination if the "not making" means finding myself at an airport I didn't intend to go. If that's for a good reason, where good reason includes economic risk management that keeps the industry going, that's fine.

    What I'm prepared to find myself in is an airplane wreck at the bottom of the Atlantic, even more so if the reason has to do with economic risk management that failed.

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  • MCM
    replied
    Remember that under the DCT plan, a fuel stopover would have required a fuel emergency declaration
    As Gabriel says, this is not correct.

    You only need to declare a fuel emergency when you are going to land with less than the minimum reserve fuel, and you need priority handling. ATC couldn't give a rats derierre if you land at your destination or for a tech stop.

    Reserves are a funny beast, especially when you consider how many airports are available for them to use along the route. At all times, they had fuel to go to a good airport, along with variable reserve to get there, and would land with fixed fuel reserve in tanks.

    What you are now talking about is commercial consistency - the fact that you might not make destination on a number of occasions. That is part of the aviation risk management system, and it is very much necessary to keep operations going. If you don't like the idea that you might not be able to make your destination, then don't fly longhaul.

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  • mfeldt
    replied
    Originally posted by Gabriel View Post
    [/list]
    On the other hand:


    Note that 63,900+1460+2200+1900=69,460 are the 69.5 t is the regulatory fuel, that matches that of plan 2 that was DTC (not RIF).

    The required fuel when landing at CDG is the 2200kg of final reserve plus the 1900kg to fly to the alternate. That's the 4.1t mentioned as needed for a legal landing.

    If the flight went exactly as planned, the trip fuel would have gone, leaving the route reserve of 1450 kg and added to the 940 kg of additional fuel that makes 2390 t of fuel that would be in the tanks, in addition to what's the regulatory minimum, when landing at CDG (again, if the flight went as planned and the route reserves are not used). That's the 2.4 t mentioned as available as "additional reserve to circumvent weather while keeping the 4.1t" required for a legal landing at CDG.

    And those 2.4 t reportedly equals to about 20 minutes of curise flight (or some 157 NM no wind, ISA, FL350, M0.82)

    If that's correct, the "regulatory" route reserves of 1460 kg would have been good for:
    20 min * 1.46/2.39 = 12 min
    157 NM * 1.46/2.39 = 96 NM

    And that would be legal route reserves for a DTC such a long flight from Rio to CDG???? It looks so, because that's basically the nmbers of flight plan 2 that was DTC.

    I tend to agree with Evan here. To my untrained eyes, that looks ridicously low for a route reserve, unless you are willing to try to land at CGD with less than alternate + 30 minutes (and maybe havinng to miss the approach and go for the alternate, landing there with less than the famous 30 minutes)

    That brings another question. How can Orly be a useful alternate to CDG??? (unless CDG gets closed for something other than weather)



    Here Huettig's seems to be wrong. As Evan said, with the fuel they had on board they had more than enough to legally file a DTC flight plan (more than needed for plan 2). So the fact that they filled an RIF fight plan doesn't seem to be of any significance. Had they filed a DTC flight plan in the same conditions, all the same concerns about the fuel reserves and the chances to need a mandatory fuel diversion would still apply exactly in the same way.

    Now I admit I'm puzzled.

    Once again the RIF strategy is NOT the issue here. If the crew was under pressure to avoid a fuel stop in this RIF flight, the pressure would have been exactly the same with a DTC flight on the same fuel at TO.

    Admittedly I'm not an expert at all in this, but can someone maybe explain to me what the RIF procedure is good for when it makes no difference at all here? What I understand is that, since there was a decision point along the route, and since circumventing the weather would have meant that at decision point legally required reserves would (possibly) not have been there any more, a stop.over would have become mandatory. Correct? Now what if you file a DCT plan without decision point, and you still realize along the way that you maybe able to reach the destination, but not with the full legal reserve required? Are you still obliged to do a stop-over? Or have you simply been spending your reserve?

    Originally posted by Peter Kesternich View Post
    Orly and CDG are at opposite sides of the Paris metro area and the weather can differ significantly between two places that are separated by 25-30kms.
    Moreover, coming from Rio, Orly is closer than CDG...

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  • Peter Kesternich
    replied
    Originally posted by Gabriel View Post
    That brings another question. How can Orly be a useful alternate to CDG??? (unless CDG gets closed for something other than weather)
    Orly and CDG are at opposite sides of the Paris metro area and the weather can differ significantly between two places that are separated by 25-30kms.

    Leave a comment:


  • Gabriel
    replied
    Originally posted by mfeldt View Post
    A legal landing at CDG would have required 4.1t of reserve fuel. If it had appeared en route that this amount could not be maintained, a technical stop would have become unavoidable
    • Thus the additional reserve to circumvent weather while keeping the 4.1t, was only 2.4t, around 20 minutes of flight time according to Huettig.
    On the other hand:

    The aircraft left the gate with a calculated weight of 233,257 kg. The estimated
    takeoff weight was 232,757 kg(11), for a maximum authorised takeoff weight of
    233 t. This takeoff weight broke down as follows:

     empty weight in operating condition: 126,010 kg,
     passenger weight: 17,615 kg (126 men, 82 women, 7 children and one baby(12)),
     weight in cargo compartment (freight and luggage): 18,732 kg,
     fuel weight: 70,400 kg.

    The on-board fuel weight corresponded to forecast trip fuel of 63,900 kg,
    route factor fuel of 1,460 kg, final reserve of 2,200 kg, fuel to alternate airport
    reserve of 1,900 kg and 940 kg additional fuel.

     Regulatory fuel:
    The regulatory fuel necessary to perform a flight is determined at brake release before
    takeoff, thus 69.5 t in this case.
    Note that 63,900+1460+2200+1900=69,460 are the 69.5 t is the regulatory fuel, that matches that of plan 2 that was DTC (not RIF).

    The required fuel when landing at CDG is the 2200kg of final reserve plus the 1900kg to fly to the alternate. That's the 4.1t mentioned as needed for a legal landing.

    If the flight went exactly as planned, the trip fuel would have gone, leaving the route reserve of 1450 kg and added to the 940 kg of additional fuel that makes 2390 t of fuel that would be in the tanks, in addition to what's the regulatory minimum, when landing at CDG (again, if the flight went as planned and the route reserves are not used). That's the 2.4 t mentioned as available as "additional reserve to circumvent weather while keeping the 4.1t" required for a legal landing at CDG.

    And those 2.4 t reportedly equals to about 20 minutes of curise flight (or some 157 NM no wind, ISA, FL350, M0.82)

    If that's correct, the "regulatory" route reserves of 1460 kg would have been good for:
    20 min * 1.46/2.39 = 12 min
    157 NM * 1.46/2.39 = 96 NM

    And that would be legal route reserves for a DTC such a long flight from Rio to CDG???? It looks so, because that's basically the nmbers of flight plan 2 that was DTC.

    I tend to agree with Evan here. To my untrained eyes, that looks ridicously low for a route reserve, unless you are willing to try to land at CGD with less than alternate + 30 minutes (and maybe havinng to miss the approach and go for the alternate, landing there with less than the famous 30 minutes)

    That brings another question. How can Orly be a useful alternate to CDG??? (unless CDG gets closed for something other than weather)

    So Huettig's commentary was not that there was an actual shortage of fuel, but simply that due to the usage of the re-clearance procedure the crew was forced to balance their decisions with fuel consumption in mind in order not to jeopardize a punctual landing at CDG already at that stage of the flight.
    Here Huettig's seems to be wrong. As Evan said, with the fuel they had on board they had more than enough to legally file a DTC flight plan (more than needed for plan 2). So the fact that they filled an RIF fight plan doesn't seem to be of any significance. Had they filed a DTC flight plan in the same conditions, all the same concerns about the fuel reserves and the chances to need a mandatory fuel diversion would still apply exactly in the same way.

    Now I admit I'm puzzled.

    Once again the RIF strategy is NOT the issue here. If the crew was under pressure to avoid a fuel stop in this RIF flight, the pressure would have been exactly the same with a DTC flight on the same fuel at TO.

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  • Gabriel
    replied
    Originally posted by Evan View Post
    Remember that under the DCT plan, a fuel stopover would have required a fuel emergency declaration.
    I don't think that that's correct.

    a) No pilot in command may allow a flight to continue toward any airport to which it has been dispatched or released if, in the opinion of the pilot in command, the flight cannot be completed safely; unless, in the opinion of the pilot in command, there is no safer procedure. In that event, continuation toward that airport is an emergency situation as set forth in Sec. 121.557.

    I don't know exactly how that works for fuel, but I think you are required to land with 30 minutes of fuel or declare an emergency.

    So if you see that you are going to arrive with less than that, you have to request a diversion for a fuel stop. If you are not granted the diversion for example due to trafic, you should declare a fuel emergency and announce that you are going to divert. If a diversion is not available of less safe that landing at the destination with less than 30 minutes of fuel, you must declare a fuel emergency and go for the destination. And note that the emergency must be declared not when you have 30 minutes of fuel, but when you note that you will be landing with less than that.

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  • Evan
    replied
    Originally posted by mfeldt View Post
    [*]If they maintained FL350 because of heavy turbulence, an additional fuel consumption of 1.5t would have resulted, bringing down the extra reserve to circumvent weather (while stiill making it legally to Paris) to 0.9t, or under 8 minutes of flight-time.
    What puzzles me is that the filed DCT flight plan (not flown) required only 69.5t fuel to convey 37.5 t of load + fuel and reserves necessary to legally arrive at Paris. The actual flight was under this weight by 1.1t and carried .9t of extra fuel. So if the reserve to circumvent weather was this thin in reality, how much thinner would it have been if flown with those numbers?

    DCT M 0.82: load 37.5 t / TOF 69.5 t
    ----------------- ----------------- ---------------
    REAL: load 36.4t / TOF 70.4 t

     Regulatory fuel:
    The regulatory fuel necessary to perform a flight is determined at brake release before takeoff, thus 69.5 t in this case.

    Based on what Prof. Huettig is saying, the regulatory fuel requirement doesn't seem adequate to me in the DCT plan. Remember that under the DCT plan, a fuel stopover would have required a fuel emergency declaration.

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  • mfeldt
    replied
    Hey,

    I got a reply from Gerhard Huettig, the Berlin Professor and Airbus pilot quoted in the "SPIEGEL" article. As it is a private message, I'm not going to post it here, but the bottom line is:

    • he's not very happy with the way the SPIEGEL put his quote into context. There was clearly no dangerous shortage of fuel
    • A legal landing at CDG would have required 4.1t of reserve fuel. If it had appeared en route that this amount could not be maintained, a technical stop would have become unavoidable
    • Thus the additional reserve to circumvent weather while keeping the 4.1t, was only 2.4t, around 20 minutes of flight time according to Huettig.
    • According to the ATC flight plan, the flight was planned to climb to FL370 at SALPU, later-on to FL390 and FL400. Since there was no more contact after INTOL, it is unclear whether the flight actually climbed any higher than FL350.
    • If they maintained FL350 because of heavy turbulence, an additional fuel consumption of 1.5t would have resulted, bringing down the extra reserve to circumvent weather (while stiill making it legally to Paris) to 0.9t, or under 8 minutes of flight-time.
    • So Huettig's commentary was not that there was an actual shortage of fuel, but simply that due to the usage of the re-clearance procedure the crew was forced to balance their decisions with fuel consumption in mind in order not to jeopardize a punctual landing at CDG already at that stage of the flight. The point being, as was discussed here, that no immediate danger would have resulted, but a delay would have been more or less certain.
    • An additional point he's making is that a B747 or A340 wouldn't have had that kind of problem on this route.


    m.

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  • mfeldt
    replied
    If I remember correctly, ships are going to set sail from the port of Recife on the 12th of March.

    m.

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  • Myndee
    replied
    Soooooo...

    Has anyone heard anything about the supposed February searches?

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  • Evan
    replied
    Originally posted by CockpitCat View Post

    Seems to be an abbreviation for "Escale Technique Facultative". According to:



    it means "Optional Technical Stop" in English.
    Français! J'aurais dû le savoir! Fie on my wretched English tongue.

    Congratulations CockpitCat. You win the Toyota Camry.

    Leave a comment:


  • mfeldt
    replied
    Sorry when some of you may think that time here was spent on a useless discussion - but I would regard being able to get background information to a sloppy-written newspaper article as a proof of excenllency for this forum.

    ETF: French: Escale Technique Facultative - facultative technical stop-over ....

    To me, it is actually still not clear, which flight-plan was actually filed to ATC, but apparently the actual fuel reserve was more than eniough. I'll try to contact the Berlin professor who was quoted in the arcticle saying that longer diversions would not have been easily possible...

    m.

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  • CockpitCat
    replied
    As to the meaning of ETF: I used www.google.fr to search for "etf bea" and found it referenced inside this report:

    www.bea.aero/docspa/2004/g-xe041025/pdf/g-xe041025.pdf

    Seems to be an abbreviation for "Escale Technique Facultative". According to:



    it means "Optional Technical Stop" in English.

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  • Evan
    replied
    Originally posted by Gabriel View Post

    For the last time, I don't agree at all.

    Not that this could not happen, but then the problem is NOT the RIF strategy. It's like saying thet the seat belt can be a safety problem because drivers would feel more safe and hence speed up with the net result of lowering the overal safety. This can happen, but the problem is NOT the safety belt. (yea, I know, not a great analogy).
    Just sent you a PM.

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