[dbloom]

In this case, "servicing" was probably referring to a heavy maintenance check.

There are several different tiers of checks, ranging from short frequent ones, to expensive, time consuming, infrequent ones: http://en.wikipedia.org/wiki/Aircraft_maintenance_checks

Usually, older aircraft that are being phased out are mothballed shortly before their next heavy maintenance check. And the resale value of used aircraft, especially older ones, is heavily influenced by how soon the next D check is.