Almost every nice Cessna aircraft I see has a new cut metal panel, to replace OEM the shock-mounted panel (on rubbers) with the plastic trim over it.
I asked a friend of mine who specialises in sheet metal, and he said 80hours of shop time to do a meticulous job, in removing all instruments in both sides. Prepare 2x new panels, texture paints them, change instrument locations etc. Certification… a bit easier on an N -reg.
Anyone else think 80 hours of shop time is too much or too little?
It’s one of those jobs that exist where you just can’t see the hours and think it’s too much.
If however you had to price it and commit to it suddenly it gets easier to see.
1. Time to plan, draw and C.A.D. get the panel into manufacture
2. Start to break down the panel and document anything and everything that can go wrong.
3. Start disconnection, marking up and documenting along the way. Wires, control cables, yokes yoke controls/switches. Air pipes
4.begin relocation processes.
5.Add new wires as stuff will change
Make up enough support for any new kit.
6 find out some stuff won’t fit where you thought……….
10. Hope stuff all fits into the cut-outs exactly as planned
11. Rewire pipe and plumb
12. Start fault finding
It’s basically a week for two guys.
If you do it and it’s nice, I may be interested.
In reality I’m way way too scared of the impending weeks of debugging.
What certification is involved? Is it structural analysis, or are there standard guidelines suggesting a particular panel thickness which takes care of it? I do recall seeing some panel thickness specs in the IMs for some avionics.
A few years ago I was involved in re-doing the RHS panel in the TB20. It can take a surprising amount of time to do a decent job. If all the instruments just “fall behind the panel” when their screws are removed (as would be the case for the round ones in your pic) then that part is quick since the wiring or plumbing doesn’t need to be disconnected, but the other stuff needs disconnecting, etc.
Relocating instruments to customer requirements is yet more work. Then drawings need producing.
However, someone who does this for a living can do it pretty fast, especially as the new panel CNC machining is subcontracted. So I think a quote based on 80hrs is allowing for some unexpected problems
I did something similar on a customer’s 182 earlier this year and I think 80 hours is a pretty good deal.
In the finest traditions of Blue Peter, here is one I did earlier.
What certification is involved for EASA-reg?
For the G500, Socata have for many years been selling an STC for the TB20 and this includes a complex structural analysis done on a computer Incidentally they used to charge €50k or so for installing this, including a GNS430W, and I don’t think many people went for that. Maybe that was a gold plated EASA 21 company job, maybe not?
For N-reg, AIUI, you do this IAW the standard repairs manual AC43-13-2B. Some UK shops have gone for a DER 8110 structural design package, but there seems to be no reason for that. I was once quoted 2k just for that, for mounting a TAS605 box in the luggage compartment.
For N-reg, AIUI, you do this IAW the standard repairs manual AC43-13-2B.
That would be all I’d intend to do if I go ahead with this job.
If you’re replacing the left floating panel on a 182 then it’s a straightforward FAA Minor Alteration in accordance with Fig 3-2 of AC43-210A. I went to Cessna to get confirmation on which panels are primary or secondary structure and they were helpful in this regard.
However, the sub-panels and right panel are classed as primary structure, so replacing these needs approved data and a Major Alteration. The way around that was to leave the original structure in place and fabricate new overlays to replace the deleted plastic parts.
Note that when fabricating new parts, you also need to satisfy AC43-18 in determining the criticality level as some parts may require approved data for production.
The certification basis is an EASA STC with minor changes.
Most of the stress analysis is by inspection as the whole panel is lighter than the original and uses the same mountings to the aircraft structure, we also used aircraft quality alloy that was slightly thicker than the original metric monkey metal panel to give a little more margin as we have in the past seen OEM panels crack.
The lower panel ( not shown ) has also been fabricated from aircraft alloy ( 2024 ) that is slightly thicker than original but as this is now the aft support for avionic racks it has been subject to a full stress analysis.
The LED lighting, ELT & traffic system are all covered by CS-STAN , the fuel flow is covered by a historic CAA minor modification. All the technical data for the mechanical and electrical installation IAW AC43 and or manufactures data.
The whole thing would not be possible without a team who are dedicated to common sense engineering and use the rules in a sensible way to progress the job rather than using the rules to find some way of making the job more difficult.
In short it’s not rocket science and should not be made so.