PPRuNe Forums - View Single Post - Hey - Any Bell 214ST pilots in here?
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Old 9th Aug 2019, 10:37
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Lingo Dan
Join Date: Jul 2007
Location: Aberdeenshire
Age: 74
Posts: 81
I have about 2500 hours on the ST but haven't flown it, or anything else, since 2007.

The biggest weakness of the ST is the engine starting system. The NiCad batteries were underpowered and the starter motors needed frequent replacement as a consequence. I believe improved batteries, and beefed-up starter motors, may now be available.

The biggest "GOTCHA" on the ST is a "High-side" failure of the engine control system and it has caught out a few people in the past. If the engine-driven alternator (which powers the engine control system) fails, or a certain one of its three windings fails IIRC, then the default arrangement is for the affected engine to go to full power: a "High-side" failure.

The serviceable engine will, meantime, reduce power in an attempt to maintain 100% RRPM. Diagnosis of this failure starts with RRPM. If it is >100%, then it's a High-Side failure. The higher of the two MGTs will indicate which is the malfunctioning engine. The torque meter is unreliable with this fault. (Cannot rememberer why)

The single most important point is NOT instinctively to dump the lever, but to contain RRPM with collective position. Lowering the lever would cause the RRPM to overspeed and, at about 117%, the affected engine overspeed trip would activate and close the engine down. The correctly-functioning engine, meanwhile, would be back at idle and would be unlikely to spool up in time to avoid this all ending in tears.

After agreeing with the non-handling pilot which is the affected engine, invite him to hold open the throttle of the GOOD engine, then you gently roll back the throttle of the "bad" engine , and slowly lower the lever when the RRPM has reduced to 100%. The good engine will spool up and the "bad" engine should be kept at a slightly lower power (by observing MGT). Then, with RRPM again at 100%, and your heart rate back to normal, find your Emergency Check List and confirm you've done it right.

I've just had a look in my cupboard for the Flight Safety's manual on the ST. It's an excellent document but, unfortunately, mine may have gone to the dustbin. If what I have written is incorrect in some way, I'm sure someone will be along to correct me!

However, what I am sure about is that you should REALLY understand how to deal with "High-side" engine malfunctions on the Bell 214 ST, and know clearly how to distinguish that from a "Low-side" failure or a simple engine failure.

In over 20 years flying the ST, in addition to other types, nothing bad happened to me. Once the engines were going (always a relief), then it was reliable and simple to operate. It's a shame that Bell didn't make an ST Mark 2!

Safe flying and enjoy the ST
Lingo Dan is online now