Lead free solder
I have read that lead free solder has 5% the shock resistance of conventional leaded solder. Leaded solder works fine on the tin plated leads of ROSH integrated circuit packages(better than unleaded). Tin whiskers are a problem with pure tin plating or unleaded solder.
The lead free solder debacle was brought to you by the Commissars in the EU even after it was obvious there were good alternatives to leaded solder. Another case of lunatic "green" policies causing harm.
The EU was worried about disposal of electronic assemblies containing lead. I'd have thought this was a disposal/re-cycling problem but they turned it into an enormous manufacturing/operational problem.
The funny thing is that of all the lead mined, 80% goes in to lead acid batteries, 5% into ammunition, around 5 to 10% in various industrial uses and a whole 1% in electronics. This was figures from 10 to 15 years ago that went around the electronics industry.
Certainly nowadays there is no more lead used in cathode ray tube leaded glass shielding (remember CRT's?) and surface mount components use vastly less solder than do through hole plated components with wires on each end.
I doubt the authorities will mandate leaded solder in aviation as it would contradict the narrative about lead being bad.