This is coolbert:
Continued difficulties and problems for another MiG warplane. Foxhound.
As seen at Strategy Page:
"Warplanes: MiG-31 Miasma"
"January 31, 2016: In late January a Russian MiG-31 jet fighter was lost due to unspecified equipment failure. The air force grounded all 120 MiG-31s until the exact cause could be determined. The most likely culprit is age which is why in late 2015 the air force received $378 million to upgrade another 50 of the older MiG-31s to the MiG-31BM standard. Unfortunately the recent crash was of a BM model as were some previous crashes. The latest crash was not unexpected. There have already been problems with recently refurbished MiG-31s. The most common problem has been the engines although one crash was due to landing gear problems. The refurbishment includes the D30F6 engines, which were tweaked and upgraded to make them more powerful, efficient and reliable. Yet there have been several crashes involving these upgraded engines. In December 2013 Russia grounded all 122 of its MiG-31 fighters after one of them crashed because both of its engines failed."
MiG-31 an air interceptor. Foxhound a stretch fuselage two-seater warplane based on the original MiG-25 Foxbat. Strictly an interceptor for air defense and not an air superiority fighter plane.
MiG warplanes for some time found to be lacking.
To be absolutely 100 % fair the difficulties in this instance is with the D30F6 engines and not with the MiG designed airframe. Those engines NOT a product of the MiG design bureau.
See previous Strategy Page articles dealing with the MiG problem, historical and present: