Some ships are more tolerant to FSD failure than others. My current Diamond Back Explorer, not so good. I've had it down to 78% and it completely failed. The FSD simply refused to charge. Luckily I had repair kits on this occasion.
My Hauler however was very tolerant and I never had repair kits with me on my journey to the core and Colonia. I just assumed the FSD would keep going with only the occasional FSD failure notice popping up from time to time.
Dispite 49% FDS I still continued on for many weeks exploring before returning to Colonia.
http://i65.tinypic.com/r0t66e.jpg
from testing its not different for each ships it really is a roll of the dice, the probability is what changed and that I don't have the figure for but...
Above 80% its business as usual FSD operates as normal
anything below 80% will give you a malfunction but wont drop you out of SC, just prevents the FSD from charging for a while "FSD MALFUNCTIONING" however this is temporary and will fix itself without the need to boot & repair, it may malfunction multiple times if your unlucky
but it will fix itself again this is a roll of the dice and I have often found my drive at 60% before even getting one failure, its RNG people!
Below 70% will again malfunction but there is a small chance to drop you out of SC too for good measure, and if that happens in a jet with a malfunctioning drive while trying to escape your just asking for trouble - its a small % chance ( I recon less than 1% ) but
CAN happen which is the important point to make as it has happened to me.
below 60% the malfunctioning drive happens more often and the drops from SC increase in frequency and continue all the way down to 1% where something will happen every jump if not a string of 3-4 faults before completing a jump.
rule of thumb is keep above 80% if you want to 100% avoid the dropping in the jets anything below 80% has a chance (even though its extremely slim / rare quite high up) to drop you from SC
final piece to the puzzle is integrity... if you have a grade 5 long range FSD chances are your integrity is rubbish, so the chance to malfunction increases, adversely fitting b spec and / or shielded FSD (is it called that?) will mean your chance to malfunction is very low
and of course if you do drop into a jet its not all bad news... don't high wake out, jump back into SC as shown in this video... Simples.
[video=youtube_share;sXE9W2pb8IE]https://youtu.be/sXE9W2pb8IE[/video]
if you feel comfortable escaping a jet then carry on, but getting a malfunctioning drive in a jet can lead to the following results which I tested in Beta;
I tested a drive to destruction dropping me in the jets with a failing drive, it is possible to escape, just need to be calm, don't panic, if your drive was already below 40% your not getting out though as it will malfunction many times while escaping and you will run out of time... or I did, in my tests I used 3 ships each time at different FSD levels (shot by a friend to varying health levels)
below 40% I have yet to get a ship successfully out -
Lost all ships trying this
40-50% and its extremely difficult but not impossible -
lost 2 out of 3 ships this way
50%-60% is a little nervous with a malfunction or two, still difficult but I have done it -
lost 2 out of 3 ships trying this
60%-70% is sometimes stress free / or can be just as problematic as 50%-60% -
lost 1 ship out of 3 (bad luck that time I feel with multiple FSD failures)
70%-80% at least one malfunction but keep calm and you will get out -
no ships lost
> 80% is the standard escape and as long as you don't panic you will jump out easy -
no ships lost
Disclaimer - these were all stock D spec & boost capable (4D thrusters) DBx's with only the FSD engineered with lowered integrity from grade 5 increased range, so results could vary with other ships / stronger drives, engineered thrusters / larger thrusters etc.
I imagine anacondas would be harder to escape with due to the usually smaller exploration drives fitted vs ship mass and slow agility (also having a boost capable ship helps escape)
enjoy