weapons and ammunition. Two Marine Corps KC-130 refueling tankers were mobilized closer to the operation, from Bahrain to Oman, to refuel the helicopters en route to Mogadishu and the two helicopters transferred from Trenton to Guam. Security detail and first evacuees Two CH-53E Super Stallions carrying a 60-man security detail—51 Marines and nine Navy SEALs—departed Guam at 02:47, from the embassy, and were expected to arrive at 06:20. They performed two aerial refuelings. During the first refueling, a pipe burst on one of the helicopters, dousing Marines in fuel and nearly forcing a return to the Guam; problems with the helicopters' navigation system also complicated the refueling rendezvous. The helicopters arrived in Mogadishu at dawn, crossing the coast just south of the harbor at in altitude on a route that was planned to avoid areas of more intense violence reported in the northern parts of the city. On their arrival in Mogadishu, the crew of the helicopters were using an outdated 1969 map, which showed the embassy in an isolated area. Furthermore, they had been told the embassy could be discerned by its white stucco perimeter wall and golf course. The embassy was, in fact, surrounded by new development and the crew saw white stucco walls around many buildings in the city. The helicopters were flying too low to spot a strobe light which was placed on the embassy's water tower (the highest point within the embassy compound) and the golf course in the embassy compound had a black, oil-coated surface—not the familiar green grass that the helicopter crew would recognize.After breaking radio silence (their only direct communication with the embassy was unencrypted) to contact the embassy, they were able to discern it and land at 07:10. As they arrived, a group of about 100 to 150 Somalis were attempting to enter the embassy compound via ladders on the wall, but scattered as the helicopters arrived. The security detail moved to establish a perimeter around the embassy compound and the Air Force's AC-130 arrived to provide overhead support. Ambassador Bishop gave the security detail clear instructions on the rules of engagement: they could only use deadly force if people came over the embassy compound's walls with obvious hostile intent. He also identified three zones of defense, stating a preference to retreat to the third zone before the use of deadly force: the entire embassy compound the Chancery, Joint Administrative Office