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Hi Geoff,
We disarm the floats after reaching Vy during after T.O checks, and arm them again at 90kts decellerating to the deck. I think due to the fact we had 2 inadvertent float deployments (on the ground) when we first got the aircraft! I'm sure you already know about that."
I understand that the first inadvertent float deployment referred to, happened on the ground after the Floats were armed and the Test button was pressed. Engineering investigations did not suggest the cause of this unexpected event and subsequently company crews were advised not to arm the floats at speeds above 80KIAS in a company Safety Instruction.
The second occurrence happened in the same aircraft under the same conditions, at a different operating base. This time the engineering investigation did reveal the cause and the problem was rectified on this airframe.
This company operates 5 different types and I can understand the desire to standardise the "Float arming procedure" for the AW139 with common practice on all their other types across the rest of the fleets, however it does appear to be counter to the advice in the RFM Supp.
I would suggest that as the Test Function was the cause of the inadvertent deployment in both cases, both of which occurred on the same aircraft, there should be no further cause for concern. However a prudent pilot might consider arming floats at 80KIAS when coasting out and subsequently increasing speed confident that the system will not deploy until its needed, ie on contact with the water.
Speds
