Classic British Flight Sim

:o :o

Similar Joe but not quite the same ;-)

Tony.. Chris.. et-al..
I wasn't making a point in my first comment. More that, given the findings of the investigation to date.. in that the fact the fire bottles were pulled before the fuel control switches were made and given the fact there was a substantial fuel leak as a consequence (though fortunately.. no fire).. I'm glad it wasn't ME in that position. I KNOW the SOP's stated the proceedure was 'shortened' (officially) so that fire bottles and fuel contol switches were to be made 'simultaneously' but that sort of thing has to make you worry a little.. or is it just me :think: Fortunately, they got away with it and a 'future' potential disaster has been averted.. not that this had anything to do with the actual crash in the first place.

ATB

DaveB :tab:

Dave - I wasn't getting at you : if anything is to be criticised here it seems to me it is the original system design - it seems bad practice to allow the use of one safety critical system ( fire bottles) to disable the subsequent use of another equally safety critical system ( the fuel cut-off)

BWS Chris

99% of the time, the fire handles will be operated and everything will work properly. The rest of the time, had the procedures been properly followed and the guys at BA who wrote the checklist not been dense, it would have worked. I say the guys at BA were dense because I (and everyone else I've worked with) have always operated under the belief that if the manufacturer puts things in a certain order on the checklist it's for a good reason and not to change that order without some serious research and consultation with the manufacturer. Just because Boeing didn't tell them to change it doesn't mean they asked Boeing to check it. Boeing most likely looked at it, didn't see any galling errors, and said "Okay" and maybe said "make sure the FO's know that they're do to the fuel cutoff levers before the captain pulls the handles." and left it at that.

The reason for isolating the control stand cut-off levers is to prevent re-opening of the fuel valves after the handles have been pulled. This happened years ago in a 707 accident and resulted in a very bad conflagration that luckily didn't claim any lives. After that, the FAA and CAA required that the fire handles prevent the fuel from being turned back on unless the fire handle was returned to its "normal" position.

Also the handles usually aren't operated AFTER the accident. They're usually operated before it, so while I applaud the crew for doing the proper procedures, honestly the Fuel cutoff switches should have been operated BEFORE impact by the captain and then the handles and bottles done after the accident was over. However, in the heat of the moment (and the short timespan in which the problem occurred), it is totally understandable and acceptable that they were unable to do this.

I don't think you are in a position to call anyone dense Chris

Garry

tell ya what Chris , get yourself up in a 777 with over 8500 hours flying them
then .... you just Show the world how , instead of Always telling them how , in planes and trains and .... whatever


k pumkin?

ChrisS wrote..

if anything is to be criticised here it seems to me it is the original system design

Bang on there Chris.. couldn't agree more ;-)

Can't wait for the next installment!! When's that due.. another 30days :think:

ATB

DaveB :tab:

Garry Russell wrote:I don't think you are in a position to call anyone dense Chris

Garry

Garry, in the sense I use it, I think it's appropriate. There is a mantra in aviation - all regulations and procedures are written in blood. In other words, things are usually written down in a certain order for a certain reason. When BA chose to change the checklist design on the emergency procedures, something that is VERY carefully written by the manufacturer, they took responsibility for any adverse results. As such, they chose to change a procedure that was sequential to a procedure that was simultaneous in spite of the fact that the manufacturer's own manuals stated that the act of pulling the fire handles isolates the fuel cut-off switches. It was dense of those re-writing the checklists to not ensure that when they were writing those procedures they were not counteracting or interfering with the operation of other systems. Had they considered the system operation, they would have not changed the procedures as they did and the problem wouldn't have occurred as the right valve would have closed.

Boeing is changing the procedure to interconnect the paths, but I think that the separation of paths is appropriate. It ensures that you have 2 separate and distinct commands to close the fuel valves when done per the published procedure. When you interconnect, you risk having a short in one system disabling or inadvertently operating the other, resulting in an unrecoverable closure of those valves.

Chris

I repeat

You are in no position to call anyone dense.

Garry

Chris Trott

I do not know how much flying experience you have - I know you have some - but I speak as one whose only emergency was an engine fire when I say that it is highly undesirable that the system was designed in such a way that the fuel cut off CANNOT be operated AFTER pulling the fire handle. It is , frankly, a dangerous piece of design and would have cost me my life

Christopher Storey

Hi Chris(T),

I think the point is that without participation and understanding of BA's drivers to change the checklist it a little difficult to aportion any criticism. BA have probably been in the business long enough to appreciate the wisdom of the official publications of the airframe manufacturers. Since we live in such a litigious society, particulary were aviation mishaps are concerned, they like most airlines will be very aware of the potential consequences of deviating from procedures, not only in terms of litigation but also insurance and public profile. Hence it behoves any airline seeking to adjust a manufacturers guidance that they do so with full cooperation, commitment and buy-in from that manufacturer. Likewise it would be remiss of the manufacturer, not to fully engage with the airline to discuss reasoning behind the request and the technical implications of any changes. Only if both parties were in full agreement that the change was viable would they be adopted. I would wager there are files of meeting minutes and e-mails to document the whole process too. The AAIB make no reference to historical process by which this was done, although you would think they have the full picture, so if they're not in a position to lay any criticism at BA and Boeings door, maybe we can hold off too

Cheers

Rich