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C510 weak battery, and starting jets in tailwind

arj1 wrote:

Why?!
Is it some SOP?

It is a limitation and can lead to burning engines. Essentially if you are in a tailwind it requires more force to get enough airflow moving through the engine to have the correct flow so when fuel is added you get a controlled flame rather than an explosion.

EGTK Oxford

According to a CJ4 pilot I know, that one has a 10kt tailwind limitation for starting. This is because a tailwind prevents enough airflow through the engine during the starting process, to get it started safely.

I wonder if airliners have such a limitation? It would cause havoc at airports.

Administrator
Shoreham EGKA, United Kingdom

Piotr_Szut wrote:

The AFM says that when charging the battery must remain on a continuous watch.

Sure that is one way to see it but I would argue trickle charging is not real charging. The very low power of such devices is not capable of heating the battery, generating gases or similar but the are different opinions. After I heard how much a new battery for our plane cost I try to keep it alive as long as possible using all available means…

Peter wrote:

According to a CJ4 pilot I know, that one has a 10kt tailwind limitation for starting.

My personal experience with the PA46 is not to combine risk factors when starting. A slight tailwind, high density altitude, remaining heat in the engine, massive heat on the ramp, a weaker than normal battery etc. are all ok if only one of them applies. But if you combine the factors the temperature peak at startup could get bad.

We had this happen once, well within all limits but still the hottest start we had so far. A slight tailwind, probably 40°C on the ramp, still some heat in the engine and the AC compressor turning with the engine. Every single factor alone would have been no issue at all.

www.ing-golze.de
EDAZ

PA46 Jetprop … 2 batteries … has no problems with any of the above

quatrelle wrote:

PA46 Jetprop … 2 batteries … has no problems with any of the above

Well it still can have problems. It just has two batteries. If the starting battery is poor it can be the same as a Meridian. If there is a tailwind, that can also affect it. If it is hot and high it can have problems.

EGTK Oxford

Having switched out Gill batteries for a Concorde in another jet I can confirm they work much better. The only negative is apparently they are less robust if multiple starts are required in short succession (>3).

Tailwind limitation seems to be mostly a citation issue. Maybe not an official procedure, but you can always dry motor the engines to get them turning in the right direction before adding fuel in a strong tailwind ;)

EGBB

Roger wrote:

Tailwind limitation seems to be mostly a citation issue

It’s predominantly a Williams issue, but also applies to many small turbofan engines. On the King Air the wind direction has minimal effect on the starts, Not surprising given the convoluted flow path through a PT6

Darley Moor, Gamston (UK)

Peter wrote:

I wonder if airliners have such a limitation?

Airliners generally have a lot more power available for starting – most of them have an APU providing prodigious amounts of pneumatic power for the starter.

Andreas IOM

Piotr_Szut wrote:

The AFM says that when charging the battery must remain on a continuous watch

The AFM of the PA46 even said, that the battery must not be charged at all while built into the plane. I assume, however, there is kind of an STC that removes this limitation….

Germany

“ I wonder if airliners have such a limitation? It would cause havoc at airports.”

Yes they do and no it’s not really a problem. Anticipation is key here. Crossbleed-start was more interesting.

EBST, Belgium
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