Thursday 20 June 2013 03:25 UTC
Where have you been? What have you seen?
This article describes an IFR trip from Shoreham (EGKA) to the island of Samothraki in Greece (near Alexandroupoli LGAL), via Brac (LDSB) in Croatia, Samos (LGSM) and back to Shoreham via Zagreb (LDZA) in Croatia, over a 2-week period.
Thanks for the, once again, excellent report.
One important note: The crazy Italian "luxury tax" has been modified and does no longer affect aircraft visiting for less than 45 consecutive days.
Many thanks for the kind comments
I hope I mentioned the 45 days in there.
It is still crazy because you could break down following a landing in Italy, or even have an emergency in its airspace and have to land there. There is an exemption for aircraft "undergoing maintenance" but frankly the only thing I might entrust to an Italian MO is a very clapped old Vespa scooter
Sorry, my careless reading – you did of course mention the 45-days-exemption. It required a lot of lobbying to get that included, originally every stay above 48 hours would have been affected.
One recommendation for a future trip: My wife and I flew to Montenegro (LYTV) this June, convenient airport with scenic approach. A fascinating small country, a bit like Croatia, but with more impressive scenery and less mass tourism ...
Sadly no, SB11 is a complete con.
Two pilots (I am one of them) who are both electronics engineers have now confirmed that this modification causes the amplifier in the servo to oscillate severely, resulting in very obvious whistling in the headsets, and a lot of RF energy getting injected into the 28V supply line which is visible on a scope.
Honeywell don't seem too bothered as they have just released this SB for general installation. I got a copy of it from Socata, under their automated mailing service.
The cause appears to be a poorly defined open loop behaviour of the MOSFET output stage, which is always marginally stable, is unstable (at RF frequencies) during a current limit condition (which fries the motor commutator pretty quick - potentially in seconds), and SB11 which removes (shorts out) a 0.33R current sensing resistor makes it much worse because it increases the voltage gain. Analysis is here (I have updated the article)
The SB is applicable only to the roll servo (KS271C) but the same issue is on the pitch servo (KS270C) which IME burns out just as often.
Today I have taken some damning videos which I will put in the article tonight, showing why the motor life in these servos is much less than it ought to be. The KC225 computer is sending an "interesting waveform" to the servo all the time, causing the motor to go back/forth by around half a revolution. This is within the backlash in the gears so the output pinion remains stationary (which, hey, is just as well ) but obviously it does trash the commutator. Especially as the waveform has fast risetimes within it which will drive the motor with the full current limit current of 2A, causing nice arcing on the commutator
Honeywell's incompetence seems to have no bounds. I haven't got a clue why, but possible reasons might be
- nobody left who knows anything about electronics, and no resources to recruit anybody (and obviously a policy decision to do that)
- several million USD made each year on sales of servos to replace the burnt out ones
- reluctance to do a fix due to legal liability, after telling everybody for 10 years there is nothing wrong
- desire to avoid having to upgrade owners who keep paying up their extended warranty
- desire to support dealers who make money replacing the servos (in some cases every 20 hours)
However Socata have just released a new rubber mounting kit for the LH and RH panels, which is supposed to deal with one of the issues: the vibration of the KI256 vacuum AI is transmitted to the roll servo (no kidding) and wears it out / blows it up eventually. And SB11 is only for the roll servo too. What nobody is admitting is that the pitch servo is equally affected, right up until you capture the preset altitude after which pitch control transfers essentially to the internal barometer and the internal accelerometer.
This kit is €95 and I am ordering one. It won't do any harm.
Phil - yes we will go there someday. Greek trips are wonderful (we love the islands) but with their airport opening times they can be quite difficult to juggle versus weather which, on the last trip, was always one day behind us... In fact we will try to do one-leg trips more, because they are so much easier.
Interesting comment you make on VFR flights and airspace access.
I have on more than one occation been declined climb into Class E by Bremen Info because they didn't have my "details". By details I assume they mean my VFR flight plan which like has gotten lost somewhere along the way, which is really no surprise.
Mostly my climb requests have been for comfort due to water crossing, so I have not found it useful to start a longer argument - maybe I will next time. Having checked, I also read the classification so that I'm not even required to ask.
Correct; Class E,F,G can be flown in, enroute, without a radio contact or any form of ATC clearance.
I say "enroute" because, obviously, for example within an ATZ things are a bit different, but you know that
The problem is that a lot of ATC units will not clear VFR flights into Classes B,C,D, for no reason other than having a laugh, which is completely wrong.
The proposed EASA EIR will deal with that nicely
My opinion (usual disclaimer ) is that the reason "everything VFR" is easy in regulatory terms, while "anything IFR" is so hard, is mostly because IFR traffic has an implicit enroute clearance, whereas with VFR traffic ATC always has the option of the magic phrase "remain OCAS" which delivers them a complete hand-washing capability. The regulatory bodies are strongly influenced by airline pilot and ATC union reps...
Who is online
Users browsing this forum: Google [Bot] and 2 guests
Login / Register