The Sukhoi SJ100 has T2CAS fitted, which allegedly offers greater protection to CFIT.
A good point was made earlier about regional data feeds to the EGPWS. Common and commercial sense suggests a Demo aircraft would have all its tricks on show to potential purchasers.
So, why did the T2CAS not alert the Test Pilots to the impending ridge?
The Russian magazine
"Moskovskij komsomolec" is reporting, that crashed aircraft was actually
replacement machine for original aircraft that developed problem with engine and was flown back home.
It is possible, that the
replacement Sukhoi SJ100 EGPWS was not uploaded with regional data?