Remember Buys Ballot's law? Stand with your back to the wind, low pressure is on your left.
OK, so you're experiencing port drift. Port drift means that, if you turn to the left, you'll be standing with your back to the wind. So low pressure must be to your left (ie, behind of you before you turned to the left).
So you're going from a lower pressure situation to a higher pressure situation.
HI-LO-HI.
or, conversely:
LO-HI-LO
Going from a LOwer pressure to a HIgher presure situation, your altimeter will read LOw. Ther aircraft will be higher than the altimeter says it is. This is the safe case.
Therefore the altimeter will be under-reading. The aircraft is actually higher.
Your mistake is to treat Performance as a self-contained study. The JAA exam system encourages you to think like that, and it isn't helpful. There aren't 14 different subjects; there's only one. It's called Flying and Airmanship. It just happens to be split into 14 different exams.
When I'm feeling expansive, I emphasise this point by telling my students how I once discovered a pitot leak by noting that the fuel-flows seemed a bit high. They all say "Surely not, fuel flows are Performance and Gas Turbines and pitot leaks are Instruments. How could you possibly have diagnosed a pitot problem from fuel-flows?" But I did, once. I'll tell you how, if you're interested.
It's all one subject.
Last edited by oxford blue; 24th Jun 2002 at 21:21.