Engine seizure

[Green 123]

High pressure rotor of turbofan engine was found to have seized during third start attempt subsequent to two hot start. do you have any idea on causes of the event?

 

[LittleInch]

Based on a one line question with Zero other details, the answer, rather unsurprisingly is no.

 

[Green 123]

Based on a one line question with Zero other details, the answer, rather unsurprisingly is no.

High pressure rotor of turbofan engine (mixed flow type/medium bypass ratio) was found to have seized during third start attempt subsequent to two hot start ,however after engine has cooled down it was started successfully. do you have any idea on causes of the event?

 

[MintJulep]

That cause was that the turny part couldn't turn anymore.

 

[LittleInch]

Have you asked the manufacturer?

I mean really, you don't say whose engine, which one, how old, why did it fail to start twice?

Clearly something is rubbing / expanding more than it should but what only god and a boroscope will tell you.

This is really like asking someone " My car wouldn't start this morning, Any idea why?"

 

[Green 123]

That cause was that the turny part couldn't turn anymore.

Turny part is high pressure spool which comprises high pressure turbine blades so one malfunction scenario is the blade tip rub that is caused by excessive differential expansion of the rotor spool and casing components during hot starts. I ask about any other possible scenarios.

 

[Green 123]

Have you asked the manufacturer?

I mean really, you don't say whose engine, which one, how old, why did it fail to start twice?

Clearly something is rubbing / expanding more than it should but what only god and a boroscope will tell you.

This is really like asking someone " My car wouldn't start this morning, Any idea why?"

Engine model: Tay650
TSN/CSN=35277/36724

 

[dtimberlake]

Confidentially I would neither assume nor presume that successful starting after cooling down means everything is now OK.

 

[mfgenggear]

OP
Was the proper procedure used to start the engine. Before running hot.
Obtain from the manufacture for proper start up. A hot start up will void warranty and damage components.
How many hours has the engine cycled.
Was it due for inspection. Which is a complete tear down and inspection.
Take pictures as it is disassemble to decipher the issue.

 

[Green 123]

OP
Was the proper procedure used to start the engine. Before running hot.
Obtain from the manufacture for proper start up. A hot start up will void warranty and damage components.
How many hours has the engine cycled.
Was it due for inspection. Which is a complete tear down and inspection.
Take pictures as it is disassemble to decipher the issue.

TSN/CSN=35277/36724
How did improper start up end up in hot start?
AMM sets out start up procedure, it is simple: 1-push start push switch 2-set start toggle switch to L/R engine 3- Once N2 becomes 15% set fuel shut off lever to open 4-when engine is stable at idle rpm push start push switch
what may goes wrong from here do you think?

 

[Green 123]

TSN/CSN=35277/36724

 

[Green 123]

Confidentially I would neither assume nor presume that successful starting after cooling down means everything is now OK.

I concur with you

 

[rb1957]

Why would you come to this corner of the internet to ask this question ? Your first stop should be the Engine manufacturer's Maintenance Manual or their customer support "help desk". If you are trying to learn, then consult the MM ... it'll include a lot of trouble shooting, or talk to the engine mechanic.

 

[btrueblood]

Other possible scenarios - oil pump cavitating and bearings seizing during hot start.

 

[Green 123]

Other possible scenarios - oil pump cavitating and bearings seizing during hot start.

Much obliged

 

[Green 123]

Why would you come to this corner of the internet to ask this question ? Your first stop should be the Engine manufacturer's Maintenance Manual or their customer support "help desk". If you are trying to learn, then consult the MM ... it'll include a lot of trouble shooting, or talk to the engine mechanic.

You can not identify the root cause of occurrences through merely consulting fault isolation section of the MM, 8D is a recognized method for RCA in which D1:use a team that is selecting and establishing a team of people with relevant knowledge.....

 

[mfgenggear]

Green
I am not an expert. But studied why turbo prop engines fail. During start up the engine is required to warm up to allow all the internal components. To thermally expand.
It is known the to quick to high rpm causes damage do to stress from un equal thermal expansion.

 

[Green 123]

Green
I am not an expert. But studied why turbo prop engines fail. During start up the engine is required to warm up to allow all the internal components. To thermally expand.
It is known the to quick to high rpm causes damage do to stress from un equal thermal expansion.

Ta muchly

 

[rb1957]

my rebuttal ... don't try to build a team out of random folks on the interweb.

 

[LittleInch]

OK, so "Hot Start" seems to be when the temperature during starting rises faster than it should leading to either automatic shutdown or controlled shutdown when the pilot notices the temperature reading.

Google seem to think this is one of

Fuel system fault putting too much fuel in
Low battery / start speed not putting enough air in
Facing the engine into the wind
Very hot day.

But basically cooking your engine is going to lead to bad things happening