A BLU-109 "bunker buster", with a hardened steel casing and JDAM guidance in the tail-fitting.
Strike missions were always prized opportunities. Aircrew involved in a strike mission had the luxury of certainty. Targets were known before launch, and quite detailed planning could occur to ensure weapons employed would produce an appropriate outcome...
While a well-executed strike mission was far more professionally satisfying than delivering weapons to a grid reference as called by a JTAC [ground spotter], the missions themselves tended to be controlled, precise and quite perfunctory in execution, despite the intricacies of coordination and the invariably outstanding results achieved.
By way of example... On 18 January 2016, Squadron Leader Adrian KIELY led four F/A-18A aircraft of 77 SQN against a cave complex near Ar Raqqah, which contained a large stock of weapons and was also being used as a safe haven for Daesh leadership in Syria. The mission, although long, was relatively straightforward, but the planning required to achieve the desired weapons-effect was far from simple.
The cave complex was situated in an area of thick gypsum, with entrances in a cliff face overlooking the small village of Ratla. Because the depth and density of gypsum provided natural protection from above, Kiely and his team sought specialist geological advice to understand and develop their options for the attack.
The eventual solution adopted was for [Hornets] Kelpie 11 and Kelpie 12 to attack the cliff face with each aircraft releasing two BLU-109 2,000lb (900 kg) hardened penetrating JDAM bombs from a fast and shallow attack profile. The idea was for the first four bombs to impact the cliff face at a 25-degree angle at 1,100ft per second. [Nearly the speed of sound!]
Those impact parameters were calculated to allow the penetrating bombs to drive deep into the cliff face before detonating and weakening the cave structure. Bombs from the second pair of aircraft would arrive from similar release parameters and collapse the cave. Working backwards from the desired point of impact, the pilots discovered they would have to release their bombs from a position directly overhead Ar Raqqah, a key Daesh stronghold.
The aircraft departed at 3:15am with Night 02, the Australian KC-30A tanker from No.33 Squadron that would accompany them, for their 2,000-kilometre transit to the target deep inside Syrian airspace. As usual, the F/A-18s refuelled during climb-out from Al Dhafra, and again after entering Iraqi airspace.
Two hours and 45 minutes after take-off, Kelpie 11 and Kelpie 12 commenced their attack from an initial point 16 nautical miles north of the target. The initial point was selected to provide the correct alignment and to ensure their bombs would hit the cliff face at the calculated angle. One minute later, Kelpie 13 and Kelpie 14 left the same initial point to release the second salvo of penetrating weapons.
The cave complex was collapsed and completely destroyed.
Their bombs produced better results than calculated. Kelpie formation made one final run across the target area to capture images of the destruction caused by their strike. At 4:18 am, Kelpie returned across the Syrian border into Iraq where Night 02 was waiting to provide their first refuel for the return trip. They flew along the Turkish border, turned south and then headed east into the rising morning sun. They landed at 8:30am and headed for breakfast.
The results of the strike attracted a lot of professional military interest. A complex targeting problem had been solved and a significant enemy facility destroyed in a clinically executed strike. Not surprisingly, such a well-executed strike grabbed the attention of the combined forces air component commander, Lieutenant General Charles BROWN of the USAF, who was provided with a detailed post-mission briefing on the Australian success.
