got it from
http://www.iaf.org.il/4417-43769-en/IAF.aspx
(EDITOR’S NOTE: It seems strange that the Israeli Air Force would send such a heavily-modified Boeing 707 to the US for maintenance.
The IAF has considerable engineering know-how and can call on state-owned Israel Aerospace Industry, one of whose lines of business is Boeing conversions, upgrades and modernization.
Why it instead prefers to have the work done in the US is unclear – unless, of course, it will be paid by the US government as part of its financial support to Israel’s military.