I am currently on holidays
with a pathetic internet connection
.
@HarryMann. This is genuine once we agree we are referring to an abnormal situation. I raise it for discussion to see if it is applicable.
@Mr Optimistic. (#1631). Thanks for the link. Most of this appears to be at 1 atm and within the normal humidity levels of air. A link that shows G variation over a larger range of variables would be
http://spaceagecontrol.com/AD-InFlig...easurement.pdf fig 62(a) This graph too is for normal humidity but you can see the trend of decreasing G with added moisture ('saturated air' in this case). I cant post the actual formula at the moment but G decreases if air has more triatomic gases in it ie also more CO2 or O3. ie the N2, CO or O2 mix doesnt matter much. This is also one reason why the term 'dry air' is used as the reference numbers quoted (ie R) to the 10th decimal place would all be 'wrong' if the air was not dry.
@Lonewolf. Yes, I am referring to high levels of moisture (not just a saturation of air with water vapour though). ABNORMALLY high amounts of moisture that are brought into the cruise level by a Cb. The M variation falls into the 'who cares' category but it is the effect of this potentially sudden change in M on the calculation of other parameters which are then scrutinised by error checking. If there was no error checking then I suggest there would not have been a problem as the error in flight data is not sufficintly significant within itself. Hence it is the handling of the variations in air properties that I believe may be an issue and may have caused HAL to give up.
@Conf. Yes, the pitots and TAT's will agree with their partners ignoring turbulance. However for a change in G the M error from a TAT/SAT calcualation is about 4 times that from a pitot M calculation. So a program checking for errors may notice an anomoly here as it checks the validity of other calculated parameters even though it is 'turbulance trained'. It all depends on the range allowed before a parameter is deemed 'not valid'.
@GB. Thanks for your welcome and comments. My point could also be phrased in terms that we did not have an 'ideal gas' in this Cb. Yes, it all hinges around the 'credibility' tests within the software which one would expect to have been determined by the range of air properties expected to have been encountered. Enter a Cb with properties outside of this range and HAL may get confused.
rgds Ian