3 engine ferry on 4 engined aircraft has been a procedure since day dot.
Done it on a DC-6, in another life.
Not sure about strapping blades, looks like they may be strapped to stators, which would seem to make sense if you want to stop rotation.
What the story was on the rest of the engines was I don't know, but boroscope and filter/chip checks are normally mandatory, maybe they were not done?
Even when they are done there are no guarantees.
I saw a PanAm L-1011 leave BGI on a 2 engine ferry to JFK and lose a second one soon after T/O. He announced he was returning due to engine failure and the controller started to issue vectors and altitudes, his response was not totally printable but in effect said "you don't understand, I am returning directly to the airport NOW, clear all traffic."
He was still dumping at touchdown and JUST made it.
Ref the damage, I have seen a JT8-D in worse shape after an incident with more than half a dozen ducks. It still ran, but only at 1.3 EPR- but even that was welcome, since the other one had also swallowed ducks and had hiccuped (sp?) twice, but kept running. This second engine had feathers from an estimated 3 ducks on the stators, but no significant damage to the fan blades.
Can one infer that a JT8-D has a limitation of 3 ducks max?
[This message has been edited by SunSeaSandfly (edited 03 April 2001).]