Poor engine reliability and lack of a suitable lead in fighter have been contributing factors, hopefully the new Hawks will help alleviate this deficiency. Very sadly this has been very costly life wise and equipment wise.
Some figures for you on aircraft losses suffered by the IAF since the mid 60's:
MiG-21 315
MiG-23 23
MiG-25 04
MiG-27 21
MiG-29 07
Jaguar 23
Mirage 2000 03
Whilst these figures are reasonably accurate, they are not necessarily government figures and will of course be contested in some cases. War losses are included as well so this must be taken into account.
