New Findings on Secret Israeli Fleet of In-Flight Refueling Planes and Advanced Bunker-Busters

The Congressional Research Center published a report for internal consumption on Sept. 28, under the heading: Israel: Possible Military Strike against Iranian Nuclear Facilities.
Authored by a group of military and intelligence experts, its main conclusion is that most of the Obama administration’s premises in the past year for opposing an Israeli strike on Iran’s nuclear program were incorrect.
Coordinator of the team was Jim Zanotti. He and Kenneth Katzman are specialists in Middle Eastern Affairs. Its other members were Jeremiah Gertler, specialist in military aviation and Steven A. Hildreth, specialist in missile defense.
They discovered Israel had pursued certain secret actions, including the development and procurement of novel military systems, about which the US had no precise information.
Their discoveries persuaded them to contest as untrue the contention that Israel’s small air force was only capable of a single strike and lacked the capacity for the wave of attacks necessary for destroying Iran’s nuclear sites. This has been a favorite argument put forward by US Defense Secretary Leon Panetta and Chairman of the Joint Chiefs of Staff Gen. Martin Dempsey.
The congressional researchers’ challenged that premise point by point.
Here are some pertinent quotes:
Although an attack on Esfahan, Natanz, and Arak might require deploying only 20% of Israel’s top-line fighters purchased from the United States, it would probably require 100% of the most capable—the IAF’s 25 F-15Is. Undertaking additional strikes on Fordow and possibly other facilities—such as those related to research, centrifuge production, uranium mining and processing, or even possible weapons production—would probably require diverting some of these aircraft from the first three targets and possibly addressing some targets through alternative means.

Israel needs only one-third of its air fleet to attack Iran’s nuclear sites

That finding ties in with the next one:
Israeli aircraft would probably need to carry close to their maximum payloads to achieve the necessary level of damage against most targets suspected of WMD activity, although any given [above-ground] structure could be destroyed with 1-3 weapons. Striking Natanz, Esfahan, and Arak simultaneously would probably require 90 tactical fighters, including a 10% margin for reliability. With support, this yields an Israeli strike “involving at least 100 aircraft.”
Most sources indicate that Israel has a total of “around 350 fighter jets, a larger aerial combat force than countries of the likes of Britain and Germany.”
This conclusion is critical because it means that Israel is perfectly capable of managing with one-third of its air fleet for dealing with Iran’s nuclear plants, leaving the other two-thirds free to cope with additional fronts, such as Syria and the Lebanese Hizballah, should the need arise.
In another disclosure, the report says that although Israel received enough 7 KC-130 refueling planes from the US to cover the round trip to Iran and back, the Israeli Air Force has also secretly developed two more refueling options about which the US knows very little.
Over the past two years, Israel Aerospace Industries-IAI bought up all the Boeing 707s coming on the international market and had them converted in IAI factories into KC-135 refueling planes.
Their exact number is not known but it is probably several dozen. However, it may be assumed that Israel’s secret squadron of combat refueling aircraft has grown into one of the largest in the world.

Israel has topped up its supply of US bunker busters

Israel quietly took another step to back up its refueling capacity, the report reveals: It developed secret technology enabling F-15I bombers to refuel F-16i bombers. The US has not found out much about the device except for its name: the Buddy Refueling System-BRS.
As for a precision-guided bunker-buster weapon for subterranean facilities, the report says that it should be presumed that aside from the American GBU-27 bombs, Israel either secretly purchased additional high-tech deep-penetration weapons systems on international weapons markets or developed them itself.
On this too, the US has little information and the Israelis are cagey.
The authors' expert conclusions are underscored in the section of the report on the Israel’s ability to attack the Fordow underground nuclear plant:
From a weaponeering perspective, Fordow offers a unique challenge. Because the facility is reportedly built inside a mountain an estimated 295 feet deep, Israel’s current earth-penetrating munitions may be ineffective. Observers suggest strikes against the reinforced entrance doors may be necessary, which would require a great degree of precision. Such an attack would not be possible with missiles, as the angle of approach required would not be possible from a ballistic trajectory.
The hard target bombs Israel has acquired from the US are bunker-busters, however, not systems designed to kill underground facilities. They could damage entrances but not the facilities. What is not known is whether Israel has its own ordnance or has secretly acquired more sophisticated systems.

Penetration not needed to disable Fordo, only shake-up of centrifuges

But the researchers add in one of their closing comments:
However, it may not be necessary to damage a facility directly in order to disrupt its functionality. Centrifuges, for example, require an enormous degree of precision to work, and even a relatively minor shock or other event can destroy a centrifuge’s utility. In the case of Natanz, even if the reinforced building is not breached, an explosion strong enough to significantly damage the walls could still ruin centrifuges—and the consensus of planners is that one to two GBU-28s would be sufficient to shatter the reinforced dome.
At Fordow, assuming that munitions would not be able to penetrate the mountainous terrain over the facility, the question would be how well the centrifuges have been isolated from shock and the possible blast effects of an attack on the facility’s entrances.
The US researchers also presume extensive Israeli use of cyber-warfare, especially to overcome the distance to be covered to Iran over unfriendly countries. They expect it to be applied to try and blind Iranian air defense and ballistic missile systems. They also foresee the Israeli Air Force flying across Syria to reach its destination after digitally dislocating Syria’s air defenses.
From there, the planes could fly over Iraqi Kurdistan and on across the border to central Iran. Only upon entering Iranian airspace, would the strike force break up into secondary clusters and fan out toward their assigned targets.