Welcome to the IREX question and answer forum. Please feel free to post your questions but more importantly also suggest answers for your forum colleagues. Bob himself or one of the other tutors will get to your question as soon as we can.
pjl147 created the topic: Emergency descent
Hi Bob, thanks for the excellent material and practice exams. One of the questions was where operating in class C airspace with severe airframe ice and turbulence and the need for an emergency descent. The two options I'm a bit confused about are (both using squawk code 7700) is whether to use a MAYDAY or PAN PAN call.
As you note in the answer, ERSA EMERG 1.7 says to use a PANPAN call.
However, in AIP GEN 3.4 5.2 (3.4 page 29) it shows MAYDAY with (iii) FUEL or EMERGENCY DESCENT. For PAN PAN on page 30, it shows only MEDICAL PRIORITY, or WEATHER DEVIATION.
It's also interesting that one is required to make a MAYDAY FUEL call if it is likely that (say with holding at an airport) the plane will land with less than its fixed fuel reserve. I would have thought it is not in immediate danger, although the severe icing does make a plane in immediate danger.