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On Nov 6, 2013, at 4:29 AM, <marv@lancair.net> wrote:

=

Posted for John Smith <john@jjts.net.au>:

>= ; I have posted on the forum a while back what I had done at that time. Belo= w,
> is an update on that=C5=A0 along with what I'm doing now.
>
> If its helpful to anyone out there= , that's good. If you're entirely happy
> with what you're doing, please still read on as you may well be able to
> provide some valuabl= e insight as to perhaps why nothing else needs to be
> done around "the Legacy Canopy".. or perhaps those that have experienced
> flight w= ith the canopy open =C2=AD what IAS did you fly the aircraft at?  Did you
> leave flaps and gear extended=C5=A0 and so on= , so you can help others understand
> how they might be able safely return for a landing with a canopy open.
>
>
> Current s= tatus
>
> Alarm
> * I have two micro switches installed in series to indicate an issue with
> the canopy
>> * One is u= nder the internal closure handle and unless the handle is in the
>> close position within ~1mm, the switch will not close
>= ;> * The other is within the pilot side cockpit opening joggle at the back of
>> tyne opening, and unless the canopy is seated to within 1= =C2=AD 2mm, the switch
>> will not close
>> * Thus if either the canopy is not seated or the internal handle is not in
>>= closed position, or if there is failure of the switches or wiring, an alarm
>> condition is identified
> * I used to have this alar= m showing up on my annunciator panel top RHS of my
> panel =C2=AD pret= ty useless to be honest when cockpit is flooded with light
> * I am fortu= nate to have dual EFIS units, so all it took was to run another
> wire to the EFIS system, and programme the EFIS to display a large red
&g= t; flashing warning "ALERT =C2=AD CANPY" both pilot side and co-pilot side. This
> accompanied with a "BEEP BEEP" happening in the headsets. = See attached
> picture of how the visual alarm appears.
>> * If I didn't have EFIS, I would have installed a very b= right LED warning
>> light pilot side and co-pilot side top of panel, along with a very loud
>>buzzer
>> or horn
>= Normal Procedures
> * My Run-Up and Line-Up checks include "CANOPY CLOSED, LOCKED, ALARMS OUT"
> Emergency Procedures
> * I have ac= knowledged that there MAY be an issue with controllability, but I
> don't plan to wait to find out for sure. So I have adopted (with the same> priority as EFATO procedures) a procedure which says "IF CANOPY OPENS AT ANY
> POINT PRIOR TO TAKE-OFF =3D> ABORT =C2=AD DO NOT PRO= CEED AIRBORNE"     Beyond that,
> and not knowing i= f this would work: "IF CANOPY OPENS IN FLIGHT AFTER
> TAKE-OFF =C2=AD MA= INTAIN 140KTS, LEAVE FLAPS / GEAR EXTENDED, CLIMB TO 500ft
> BEFORE POSITIONING FOR APPROACH TO LAND NOT BELOW 100kts"
>
> In my op= inion, no Legacy should fly without the above =C2=AD or put another way,
> I can't see the downside for essentially a few micro switches a= nd
> recognition of some very simple procedures. I'm sure that many will argue
> that the alarm as described above is not helpful =C2=AD b= ut take a look at the
> picture and ask, is it more likely than not th= at you would notice this red
> flashing warning as you line up and &= nbsp;/ or commence a take-off roll? UNLESS
> take-off is done without any reference to instruments - but assuming that
> was the cas= e, and canopy is not locked, it presumes both Run-UP and Line-UP
> checks have also been ignored =C2=AD tends to suggest a different problem al= l
> together.
>
> But at the same time, I absolutely recognise that there will be times when
> no amount of alarms, warning= s, procedures won't protect =C2=AD but on balance, I
> find it hard to= argue that they won't reduce risk.
>
>
> What I'm doing n= ow
> * Over the last month or so, I have been working up a number of ideas for an
> automatic secondary latching or restraint mechanism.= In some cases, pretty
> much to the point where CAD drawings could be put together and DXF files fed
> into a CNC machine. But =C2=AD not= so fast. Each idea needs to be screened
> against all the obvious =C2= =AD net benefit, reliability, simplicity, operability
> (latter must be from p= erspectives of a pilot, passenger and rescuer). I'm
> used to the term HAZOP (hazard and operability assessment) =C2=AD sounds fancy /
>= complex but its pretty straightforward (identify failure modes, operability
> issues etc=C5=A0 rank as a function of likelihood or pro= bability etc.).  However,
> it does rely on a group of infor= med persons contributing to make sure that,
> as far as is practicable, no= thing is missed and the best solution is
> uncovered
> * The geometry and structure of the canopy and hull make for some
> challeng= es, as does also managing retrofitting something to a shiny
> completed machine =C2=AD but I'm sure it can be done
> * I have as it h= appens physically seen the SS spring steel device used on a
> VariEze =C2= =AD it may ultimately be the best solution but right now, my concern
> is o= ver a "rescuer" begin able to quickly find, reach and then operate the
> spring steel tab under difficult conditions. Beyond this idea, I= have thus
> far explored ideas ranging from inertia reel seat belt devices attached to
> the top of the canopy, electric solenoid operate= d pins that self latch but
> require power to open (self contained battery!), pneumatic solenoid
> equivalents, and mechanical linkage va= riants!  All have their pro's and
> con's =C2=AD but my "spe= c" if you like is essentially this:-
>> * Must automatically latch whe= n the canopy is lowered (as some have
>>suggested
>> =C2=AD= like a car bonnet safety latch)
>> * Must be obvious and easily ope= rated and released by pilot, passenger or
>> rescuer
>> * Must have alternative emergency opening capability (this is the scenario>> where the auto latch does it trick when you put the plane away after a fly,
>> and you come along some other day and the normal ex= ternal release has
>> failed=C5=A0..)
>> * Goes without saying that any device needs to be as simple as it can
>> practical= ly be, and should ideally be relatively easily accommodated within
>> the geometry / structure of the Legacy so it doesn't beco= me a deterrent for
>> folks to install / retrofit to an already completed aircraft
> * I need to do a bit more work around some design= s / drawings for the above
> ideas, and then I'd be in a position to share those with the objective and
> working collaboratively to find a= solution =C2=AD the more brains and pounds of
> experience we can bri= ng to bear =C2=AD the better!
> * BUT who knows =C2=AD the conclusion dra= wn from looking at secondary latch ideas
> may very well be that the r= isks and consequences of installing a secondary
> latch outweigh the perceived b= enefits =3D> "do nothing". At least the election
> can be a better informed election. As some say, or words to effect=C5=A0. "If you
> kn= ow why you do or don't do something, it might help=C5=A0..
> * However= , the process of dialogue throws up some quite different ideas /
> approache= s / possibilities
>> * Fred Moreno and a colleague have pondered whether damped gas struts that
>>may
>> offer the potenti= al to stop the reported oscillating canopy scenario (most
>> recently observed with VH-ALP)
>> * Is it possible that IF the cano= py opens in flight, it only lifts a small
>> amount and is stable (as some have observed and experienced) IF the ball is
>> centered;= may be, just may be, if there are rapid power changes and / or the
>> ball is not way off centre -  does the slip invite= the air flow to come up
>> under the canopy and push it up higher (and drop if slip is removed)?
>> * A recent post reports a c= anopy rises when full power is applied (and I
>> presume therefore nowhere near becoming airborne?) - may be all Legacy
>>o= wners
>> need to go out and check that for their aircraft this does occur, because if
>> does, well=C5=A0 pretty much the obvious<= br>>> * Some report no issues if the canopy opens in flight - which surely begs
>>the
>> question =C2=AD why do some? &n= bsp;So don't we need to try and fathom out why this
>>might
>> be =C2=AD what have some done, but others not?=
>
> Anyways =C2=AD I'd like to hear from anyone who wants to w= ork together to share
> and develop / assess ideas for a secondary latch (= or not as the case may
> be!) and develop sound (perhaps experience based?) emergency procedures. May
> be we can split it up =C2=AD a gro= up looking at latches?  A group looking at
> emergency procedures / how to fly safely with a canopy open?     A= ny
> volunteers?
>
>
>
> Cheers,
>
> John
> VH-XTZ
>
> John N G Smith
> Tel / f= ax:    +61-8-9385-8891
> Mobile:      +61-409-372-975
> Email:&nb= sp;        john@jjts.net.au
>
>

<Canopy Alert.jpg>

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