The initial excuse was that the Halo's transit papers weren't in order, after Sudanese authorities became suspicious of the helicopter setting down nine times inside the Dafur region. The government also found an unspecified number of locations marked on the crew's maps, all in Darfur state. They think the Russians were bringing in munitions to the Sudan Liberation Movement (SLM).
The Russians applied heavy diplomatic pressure on the Sudanese almost immediately after the flight was grounded. The huge helicopter was carrying thirteen people (six of whom were crew, along with two technicians and two managers) when Sudanese military authorities detained it in El Fasher on July 21. The Russians also claim that the crew had all of the over-flight permits needed along its route, including Russia, Ukraine, Turkey, Greece, Cyprus, Egypt, Sudan, Chad, Cameroon and the Congo. The Vertikal-T air carrier has a large fleet of Mi-8 and Mi-26 helicopters on contract flights both inside and outside of Russia.
Even if Vertikal-T gets their helicopter back, this delay is going to cost the UN alot of money. MONUC relies on several hired helicopters to provide logistical support and had first hired two Mi-26s in November 2001, for a minimum of $12,000 per hour. - Adam Geibel
The Sudanese authorities released the crew of the Mi-26T 'Halo' helicopter owned by the Vertikal-T airline company, who are now at the residence of the Russian ambassador in Khartoum. The Mi-26 was under UN contract to bring in humanitarian supplies to peacekeepers in the Congo, but the Sudanese authorities claimed that it was performing a military mission and did not have the appropriate over flight permission. The helicopter remains in Khartoum, under guard.