Originally Posted by
John R81
I believe that the reason behind the regulation is that originally helicopters all had piston engines, which were less reliable than they are today. The rule was made and never revoked, despite engines becoming more reliable.
Philosophical question: are engines more reliable today?
From a design and manufacturing perspective components are possibly of a more consistent quality, but failures almost always end up due to poor or lack of maintenance, or poor installation.
The human aspects have not changed.
The volumes of flight hours have increased, as has urban density so if anything the risks are greater now than they were before.