AS350 Question

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tailrotor
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AS350 Question

Postby tailrotor » Sun Sep 24 2017, 07:59

Hello All,

I realise that this is a pretty ambiguous question but if anyone with experience on the AS350 particularly BA variants would like to chip in it I would be much obliged.

My question is "how much rise in NG would you expect from a 1B engine if the OAT rose from 20 to 25 degrees?"

I recently did a trend check (75% torque 1000ft AC off) as I have been doing for all my flights for the last 6 month in this machine but noticed a 1-1.5% rise in the NG under these conditions. As it has been winter and this has been the first "hot" day I have have flown it I don't have anything to compare it to so I was wondering if anyone could confirm if this is a normal change with the temperature difference or if it might be something else.

Kind regards in advance.
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Twistgrip
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Re: AS350 Question

Postby Twistgrip » Sun Sep 24 2017, 08:20

Have you looked at your power assurance chart?.This should give you an indication as to the performance and margins your engine should be delivering.
If in doubt talk to your LAME or engineering department.
"You can watch things happen, you can make things happen or you can wonder what happened!!"
Firefish
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Re: AS350 Question

Postby Firefish » Sun Sep 24 2017, 09:50

Humidity plays a big role too. Higher humidity, higher NG.
Justwannasearch
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Re: AS350 Question

Postby Justwannasearch » Sun Sep 24 2017, 21:58

If you're only checking it at 75% torque, are you sure the bleed valve light is out?
You're better off pulling up to MCP or checking it at higher alt
LVDT
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Re: AS350 Question

Postby LVDT » Mon Sep 25 2017, 16:28

As has been mentioned so far..............
+
Beware of using your own dreamed up parameters for "trend" checking as they could easily be irrelevant.

On a 1B engine the bleed valve closing is based on NG only and is activated by the "tacho box".

Depending on the ambient conditions the bleed valve closing and the use of 75% Q could be all over the place.
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100ft
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Re: AS350 Question

Postby 100ft » Mon Sep 25 2017, 21:15

Do a proper Power Assurance check described in the flight manual.
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rex bivouac
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Re: AS350 Question

Postby rex bivouac » Tue Sep 26 2017, 02:50

What Julian said.

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