Trend Info for secondary systems?

[Low Fidelity]

Hi all,

Thanks to everybody that contributed info to my last thesis proposal it was very useful. However in light of gentle pressure from my supervisor I have changed track a little :hmm: . So here goes!

The whole thing basically stems from a story I once heard about a pilot flying a long haul route somewhere over Siberia (A340 i think). During the flight the pilot notices a decrease in quantity/pressure (can't remember which) in one of the hydraulic systems. The first thing he really wanted to know was how rapidly the levels were decreasing so that he could make tactical plans (e.g. immediate divert or continue to more suitable destination) but apparently this kind of trend info isn't immediately available. He subsequently went on to make regular checks of the system, collect data and make a mental plot of the systems behaviour over time. (is this just SOP?)

So what I need from you guys in the know is:

- Is this situation realistic? is this kind of info available on the FD?
- If not, are there good reasons why not? (tech limits, human factors etc..)
- If this kind of situation develops how would you normally deal with it?
- Do you think it would be beneficial to display trend information? (not just on the hydraulic systems but maybe fuel etc..)
- Is this whole post just a waste of time? :uhoh:

Thanks for reading this and I apologise If i seem a bit naive but I'm far from an airline pilot, just a pen pushing student!

Regards

Low Fi

[scroggs]

Trend information is not displayed in the current generation of Airbus aircraft, and thus any quantitive displays must be regularly checked to ensure that there is no loss or, if there is, that the rate of loss is not critical. The rate must be established by the pilot's own calculations and, if the rate of loss is potentially critical, a plan to contain the situation must be evolved. This is all SOP.

I would imagine that the reason there is no rate of change information for most parameters is that the computational power available to the designers when the systems were being developed was insufficient - and probably that trend information had never been asked for!

Fuel is already displayed in trend form as a projected Fuel On Board at future waypoints and destination/alternate and as a fuel flow per engine. Trend information for other resources could well be useful, if the software algorithms were robust enough to ignore temporary changes brought about by air density, temperature, service use etc.

[Low Fidelity]

Thanks Scroggs, good food for thought.

Currently stuck in a literature search but there's very little out there :(

Hopefully something will turn up!

Regards

Low Fi