My experience doing occurrence reports is that while the (foreign) CAAs don’t seem to answer the systemic issues I raise, there is exactly zero unpleasant consequences, including when the occurrence is formally/legally/juridically “my fault”. A few examples.
The PIC of a flight where I was crew, too, issued a mayday in France due to icing around 2016/2017. I don’t think he made any paperwork / MOR / declaration, and I never heard that any question came his way, and I know for certain no question came to the operator / owner of the plane. After landing, we saw a SIGMET for the area that we passed; it is plausible the SIGMET was issued consequent to our mayday.
I did safety occurrence reports by email to the authority and/or on https://aviationreporting.eu/ several times, also a handful of times following an error of mine, not least one time for a runway incursion without clearance in Spain. The airport also contacted me afterwards to get my statement (I forwarded them the statement I had already done to the authority). I just got a terse reply from the Spanish authority “Based on the information provided, we have decided do not open a formal Investigation.” and from the Luxembourg authority "Thank you for your report. [We] closed the occurrence with a classification as " incident"."
When I got an in-flight alternator failure, I issued a pan pan. I did my report on https://aviationreporting.eu/; I got the CAAs standard answer of:
Please be informed that your report is now listed in our safety database with occurrence file number LUX-001313/2020.
For the moment being, no further action is required from your side. If more information is needed, we will contact you again.Thank you for the report and your cooperation in the field of aviation safety.
The PIC of a flight where I was crew, too, issued a mayday in France due to icing around 2016/2017
Did he canceled mayday while airborne and flew according to his plan? or he kept it all the way to another runway?
I think self-raised mandatory MOR (or voluntary VOR) get sucked into black holes 
I would never ever file an MOR unless I was forced to.
You never know where it might lead. Your flights are logged on FR24 etc for a very long time. The national CAAs employ loads of people who really don’t have very much useful stuff to do. As I write this, I am 100% certain there are dozens of CAA people reading this thread They also have people who like to watch particular pilots who have developed a “bit of a history”; this is a standard ex police kind of thing.
This is an example of an MOR which is likely to cause a lot of trouble in the future.
If you have to declare a PAN or a Mayday, do so. It is always the right thing to do. But once safely on the ground, keep a low profile
You may have made a mistake, or ATC may have made a mistake and they will not be happy for you to cause the tape recordings to be examined. Especially if there is an ELP issue; this is a super hot topic around Europe which results in countless misunderstandings.
I think self-raised mandatory MOR (or voluntary VOR) get sucked into black holes
Sounds resonable ;-) … even from MOR done by ATC you seem to rarely hear anything again, which is a pity – wasn’t that supposed to be a tool for raising safety for pilots too?
wasn’t that supposed to be a tool for raising safety for pilots too?
When the data is gather in aggregate & anonymised fashion: YES
To beef up the prosecution folder: NO 
Ibra wrote:
Did he canceled mayday while airborne and flew according to his plan? or he kept it all the way to another runway?
Yes, we cancelled the mayday while airborne. The story was that ice was accumulating and we were not getting a descent clearance “fast enough” due to need to coordinate with the controller of the lower airspace. Airspeed indication had already lost 20kts, then went to zero, at which point he took controls, descended without clearance and issued a mayday. When out of IMC and in positive temperature, we “saw” that the plane was flying just fine and understood it was “nothing more” than pitot icing. We cancelled mayday and continued to the originally planned destination at lower cruising level, we had enough extra fuel for the extra fuel burn.
The passenger obviously heard it all, including ATC advising us of the closest aerodrome…
Yes, we cancelled the mayday while airborne.
Did you transmit 7700?
As I understood from talks it may make a difference whether you are ‘in the electronic systems’ by 7700 or not – which is counteracting safety thinking imho too.
MichaLSA wrote:
Did you transmit 7700?
No. Fiddling with the transponder was not our priority.
I declared Mayday few years ago when I had to shutdown one engine on DA42 due to coolant leak. I landed with one engine to planned destination (LDZA) because it was the closest opened airport at that moment. Nobody has ever contacted me or asked any additional information.
MichaLSA wrote:
It may have been easier when I had landed ‘somewhere’, as Germany has some special ongoing with airstrips being non-existent when outside ‘opening hours’.
That is very concerning.
Also how can one get fined for engine trouble? Unless empty tanks are the reason, I mean.
