an anti-tank guided missile battalion, as they would not have any armor support for nearly 12 hours. In addition, the Egyptians had built separate ramps at the crossing points, reaching as high as to counter the Israeli sand wall, provide covering fire for the assaulting infantry and to counter the first Israeli armored counterattacks. The Egyptian Army put great effort into finding a quick and effective way of breaching the Israeli defenses. The Israelis had built large 18-metre (59 foot) high sand walls with a 60-degree slope and reinforced with concrete at the water line. Egyptian engineers initially experimented with explosive charges and bulldozers to clear the obstacles, before a junior officer proposed using high pressure water cannons. The idea was tested and found to be a sound one, and several high pressure water cannons were imported from Britain and East Germany. The water cannons effectively breached the sand walls using water from the canal. At 2:00 pm on October 6, Operation Badr began with a large airstrike. More than 200 Egyptian aircraft conducted simultaneous strikes against three airbases, Hawk missile batteries, three command centers, artillery positions, and several radar installations. Airfields at Refidim and Bir Tamada were temporarily put out of service, and damage was inflicted on a Hawk battery at Ophir. The aerial assault was coupled with a barrage from more than 2,000 artillery pieces for a period of 53 minutes against the Bar Lev Line and rear area command posts and concentration bases. Author Andrew McGregor claimed that the success of the first strike negated the need for a second planned strike. Egypt acknowledged the loss of five aircraft during the attack. Kenneth Pollack wrote that 18 Egyptian aircraft were shot down, and that these losses prompted the cancellation of the second planned wave. In one notable engagement during this period, a pair of Israeli F-4E Phantoms challenged 28 Egyptian MiGs over Sharm el-Sheikh and within half an hour, shot down seven or eight MiGs with no losses. One of the Egyptian pilots killed was Captain Atef Sadat, President Sadat's half-brother. Simultaneously, 14 Egyptian Tupolev Tu-16 bombers attacked Israeli targets in the Sinai with Kelt missiles, while another two Egyptian Tupolevs fired two Kelt missiles at a radar station in central Israel. One missile was shot down by a patrolling Israeli Mirage fighter, and the second fell into the sea. The attack was an attempt to warn