Noise limits
I thought all original ( IE not PS-90 engined) IL-76/78 aircraft were banned from US air space as they are not CAT3 noise and emissions compliant.
I suppose the same loophole that fits the B.737-200 (AKA CT-43A) aircraft EG&G fly the famous "Janet" flights out of Las Vagas McCarren to mysterious points in the Nevada Test Range fits this as well.
Be lucky
David