"Core lock" after flameout. Known problem?
 

Hi all,

just read this interesting article on the Pinnacle crash: http://www.flightglobal.com/Articles...CF34+test.html

Were any of you aware of a problem called "core lock" (zero rotation in a jet engine due to thermal stress after a flameout)?

Cheers

Once upon a time I was ground running a RB211-524 when we ran out of oil , due to a leak and my inattention, and stopped the engine without cooling it down. It seized, and we could not restart it. We ended up changing it as the aircraft was required for service. The next day, the engine shop found no fault with it after it had cooled down!

Not at all unusual on engines w/ tight clearances (fresh from shop). The cause, well covered in the RJ thread, is the hot lightweight casing cooling faster than the massive rotor disks. Patience is the cure.

Just wondering would this event only occur in jet engines or would it be possible on turboprops as well ???

It's definitely possible on ANY turbine, given tight enough clearances, which is the recipe for low fuel burn.

A double-edged sword.

At academic level, core lock was known, although it's mightily uncommon. I wonder what will this CF34 testing come down to. I guess there are not many test pilots willing to exactly replicate the Pinnacle flight.