In fairness I don’t think the competence of the people involved was an issue.

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The guys doing the work, were NOT the one’s I was referring to – it was the plethora of muppets both in ‘internet-land’ and spouting H&S legislation out of their posteriors at the skilled and qualified crew who were trying to operate a safe system.

Well, my Thorpe is 3/4 built and to be fair, does have a huge number of holes… most down to missing skins, BUT I have a large collection of smaller access panels and they are going to fit somewhere… We’ll see. The Thorpe is an odd aeroplane anyway.

As for not being able to reach parts of the rear fuselage – if you can see an issue, then you can effect a repair which may involve replacement of the appropriate skins. There’s not much going on back there, and chances are any defect in the fuselage tubes or bulkhead would require the skins to be removed anyway…. ergo, no panel needed, just periodic inspections every 500 hours (guess!) which require the removal of skin areas (Plus you have those turnbuckle access panels which you can get at least one hand into without issue). You don’t need to access every part of the structure for a pre-flight or 50 hour check. For more in-depth inspections, you may need to remove or replace skin panels, but since its a major inspection there’s no issue. Therein lies the reasons for the varying level of checks and inspections. Without external influence through things like collision or lightning strike (abnormal events), the tailplane is not just going to drop off mid-flight due to an issue which was not identified on your pre-flight or 50 hour inspection. Major issues like that tend to take a long time to develop and they will be identified as a possible hazard during the design stage and factored in to the longer checks as appropriate.

I stand firm with my point ealier about the wing box and tail section – why allow moisture into the structure via a panel when no harm will come of it if it’s built correctly? The manufacturers will know the likely problems with fasteners, materials, structures and fittings in that area and the maintenance schedule should reflect that.

Again, I re-iterate: IF you have found a particular problem with the design, ask the manufacturer about it, oir submit a Mod form. Simple.

I’d be slightly concerned if a main spar inspection required the removal of skins which are connected to the spar, but otherwise you’re looking at investing in a boroscope or fibrescope, a mirror on a stick, and a damn good torch. (or if you’re not an inspector, get them to do it 🙂 )

Finally, leave the lack of access to bag tanks with me for a few minutes and I’m sure I’ll be able to find a couple of examples other than the Jet Provost (just one that I know, and yes, I KNOW its not a comparable airframe…) where the tanks are easilly removable…

Progress 1: (21:37) The Piper range of light aircraft seem to have integral tanks (structural), so you can’t remove the tanks without the wing falling apart unless you trestle and rig the wing. You can see three of the six sides just by looking from the outside, and you can get a mirror into the tank by the filler cap. Any more holes to see the inside, and you’ll struggle to keep fuel in… removal of the tank is possible for detailed inspection / pressure testing, etc, but not pre-flight. The only aircraft I can think of which has panels such as what you want, are the Lancaster and Shackleton where you have 10ft square panels to allow the removal of the rigid tanks. Having removed said tanks, I don’t recommend doing it on a regular basis. (Why would you want to?) There is no facility to look at the top of the tank when it is fitted, and again unless it’s broke, I’m not interested in it.

Progress 2: (21:49) Wing Bladder tanks are actually quite rare these days, especially in home-built aircraft because of the issues regarding their removal. So in the space of 15 minutes, I’ve found a reference to the process of removing one from a Twin Commanche (PA-30). It seems they haven’t got any easier 😉 As per usual, the hole is as small as possible to retain structural integrity whilst allowing access to the tank, IF you have skinny hands and an eyeball on a stalk. Such is life!

4 access panels on the Cessna 182 for access to the bag tanks…

It also appears that you do have support in your quest to a point… alot of engineers are currently complaining about the size of access panels in the integral tanks of Airbus products.

So… now at last I can see what your issue is, BUT I’d still say that maintaining structural integrity is more important than being able to access everywhere.

Mod for a Rans regarding access to the firewall. (non-structural mod) http://www.pipcom.com/~cowcam/rans%20panel%20access.htm

Mentions of a Mod to gain access to Europa aircraft rear fuselages to remedy an issue: http://www.auf.asn.au/airworthiness/AN160807-1.pdf

Here’s a partial quote by a chap named Tom hunter on another forum about modifications to Thorp T18s :
“I am working on a T-18 that has been flying for 34 years and is built according to the plans with regard to no rear access panel. The push pull tube had never been out of the plane and since there is no way to get to that rear bushing in the tube without removing the rudder, the fin and the horizontal stab, it had never seen any service. After 34 years the bushing was frozen in the fitting on the end of the push pull tube. So for those of you who have older Thorps with no access panel on the rear fuselage, you should add one for a couple reasons. One, so you can inspect and service that rear bushing in the push pull tube. Two, so you can inspect the 4130 fittings that your tail wheel mounts to. And three, so you can inspect the jack screw assembly plus lube it. The problems that you will encounter by ignoring the service requirement for the above items are much more real than any imagined loss of skin load carrying capability.

In addition I would urge anyone with an older Thorp to check the rudder for play on the lower hinge. If proper service is ignored for this point, the hole in the lower rudder hinge will become oblong and the bushing will have excessive play. Let this go too long, and you will need to purchase another lower rudder hinge or machine one.

The wing skin templates from John’s shop (years ago) in Burbank did include a 1/8 hole in the top and bottom of the wing directly above the aileron pivot point so in the future if you needed to remove the bolt, you could drill out with a step drill so you could use an extension and socket to remove the pivot bolt to get at the bushing and then install a button cap on the skin when you are finished.”
http://www.thorp18.com/forum/topic.asp?ARCHIVE=true&TOPIC_ID=5794

It seems that the system for detecting issues and then performing modifications does actually work. When you find part of the wing or tail structure developing faults which really requires access to investigate further, highlight a Mod to the inspector, and you shall have access provided that it doesn’t compromise the hull. 😀 I think I’ve vented my spleen enough now, so I shall stop and leave you to your thoughts

Either way, I’d follow the pre-flight inspection word for word, plus anything extra which you are aware of and is accessible. Chopping holes in an aeroplane is generally a bad idea, as id deviating from the routines specified in the relevant maintenance / inspection manual.

Pilots prodding around in places they don’t need to be is the biggest flight safety issue here. (Unless you believe there is cause for genuine access, in which case submit a modification request and grab your drill…..)

I don’t see why anyone would want more holes in their aircraft than was absolutely neccessary. My Piper Aztec C has a total of 78 access panels – more than enough!

Regards, John Applegarth, Airframes and Engines lecturer (Time-served maintenance mechanic…. damn I wish I was an inspector….:D .)

Buy a smaller monitor. I have the same issue, but I don’t moan about it. I like reading the page in the format it is. If it was an all-singing and dancing forum which adjusted to the size of your screen, it would run EVEN slower!

This is limited, but good fun for the basics: NASA’s Engine sim

http://www.grc.nasa.gov/WWW/k-12/airplane/ngnsim.html

There is also an aerodynamics version – Foil Sim

http://www.grc.nasa.gov/WWW/k-12/airplane/foil3.html

Stressed skin is defined by the fact that it is structural, ie. it is under stress. If you remove upper wing stressed skin, or even stressed panels, without the correct (according to the AMM/AP) supports, the wing geometry will change and you will have killed your aeroplane.