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Pre-first flight inspections

444TX

Well Known Member
Building RV's has become more popular and increasingly easy to accomplish.
There are now quickbuild kits, baffle kits, firewall forward kits, wiring kits,
prewired avionics, etc. After assisting an area tech inspecter on many pre DAR inspections it has become clear that there are rules in construction that are not followed by many builders. A large area of knowledge is unknown, not being picked up or taught. This information is not in the plans, directions and publications used by builders. Many of these items are common sense, but errors repeatedly show up.

1.SPAR BOLTS
The last two planes inspected had the AN4-13A center spar bolts missing. This is not entirely the fault of the builder, but shows that one must be extra vigilant. The match-hole builder now uses plan #80 which does not show the bolts. The builder had used plan #11 which shows the NAS bolts on one side and the AN4's on the other side of the spar. Finally the AN4's are not in the NAS bag. I would recommend marking all spar bolts with inspection paint after final torquing to leave an easy way to verify they were done. All flying planes with CNC spars should check for missing bolts. The AN4's can be checked at the wing root. Look at the nut plates in front of the spar, up inside the fuselage, with a mirror. Two quickbuild 7s had multiple rivits on the top of the spar missing. They were most likely used on an A model, for the gear weldments, but were empty. Fuel tank to fuselage bolts are often too tight, too loose or not safetied. I have seen them all. Watch the edge distance on the rear spar attach, be sure it is properly torqued/pulled tight and cotter keyed.

(Van's now has a service bulletin, SB 12-08-04, 14 August 2012. After calling, and being ignored, they finally put out a bulletin on this. All older planes should be checked)

2. CLEARANCES
Many planes have control rods too close to structures. Aileron to bellcrank rods thru the rear wing spar and flap actuator rods thru the fuselage are the main ones, but there are other similar places on the plane. Have at least 1/16 inch clearance thru the entire travel, 1/8 inch would better. Watch for anything rubbing on the main aileron tubes inside the fuselage. Keep all wiring and antennae cables clear.
Control clearances are many times too tight. Flap to aileron, aileron to wingtip, elevator to horizontal stabilizer and the rudder horn. Look at the counter weights and on the end of the horns. 1/8th inch minimum.
On a constant speed prop one can clamp a couple of boards to a blade and twist it to verify spinner clearance.

3. CONTROL ANGLES
Many planes do not have enough elevator travel and/or too much rudder travel. Set the angles. Cut out material for the elevator stops, make the stops hit both sides even though they are many times offset and uneven. Build new rudder stops if you have to. Install the aileron stops. Some planes have none. There have been instances of flaps popping out from under the wing when fully deployed. I have seen none with the ability to do that, but look at the amount of flap under the wing and verify. More flap angle than specs is OK as long as it can not come out. The angle is set by the motor travel, not stops.

4. FLIGHT CONTROL RODS
There should be no excess threads on rod ends. If both jamb nuts come loose the rod should not spin off a rod end. Readjust, add an extra jamb nut, or build a new control rod if necessary. Be sure there is no way something can go over center. Ailerons with no stops and auto pilot controls are the places to look. Check all jamb nuts. Many times one or more are found loose on inspection. Mark across the nut and tube with a marker or inspection paint when checked for the final time. Check and mark all control hardware.

5. FUEL SYSTEMS
Watch out for changes to the plans. Aftermarket race car fuel pumps, gascolators after the electric pump on an injected motor, glass fuel filters, added tanks. Thinks things through carefully. Loose fuel nuts. Check everyone before first flight and mark them with inspection paint. More than one person has had a leak or performance problems from loose fuel nuts. Fuel pickups should be right against the quick drain. It is easy to verify before adding fuel. Make sure all fuel system service bulletins are complied with. Fuel selectors. Builders should verify all selector positions. Blow thru it and know what it does. Do not assume. It is also a good idea to run 5-10 gallons thru the lines in both positions. Verify that you obtain idle/full throttle, full rich/mixture cutoff, and full prop. All controls should have slight springback. It is often neccessary to drill a hole closer to the pivot on the fuel servo when a quadrant is used.

It is hard to go wrong following the plans.

6. BOLT SELECTION
Many times bolts are found with incorrect thread counts. You do not want a nut bottomed on the shank of the bolt or too few threads showing. The plans are sometimes off, use the correct length fastener for the application.
Horizontal front spar to fuselage seems to be a place for errors. It is the first place to check on the tail.

7. ENGINE
There are many places for problems. Clamps on the C/S oil line, non-safety wired alternator hardware, covers missing on battery cable ends, plug leads loose, exhaust brackets poorly secured, wire and hose runs unsecured, air intakes not safetied, no drain hole in fab/snorkel, missing sniffle valve, engine mounts incorrectly installed, etc. This a place for many small missed items. Look at other planes and use common sense.

8. WEIGHT and BALANCE
Check it carefully and start out in the middle. Add baggage if neccessary. First flight is not the time to experimant with the edges of the CG envelope.

Have a tech inspector that is very knowledgable in RV's or several good builders in the area inspect the plane before first flight. Anyone helping to build the plane is a poor candidate for the inspection. A fresh set of eyes can find items repeatedly overlooked. Do not count on the DAR to check things well. It is the builders responsibility to make sure things are right.

Be carefull out there. Small mistakes can have terrible consequences.

George Meketa
RV8 - 910 hrs

P.S. sorry for any spelling or grammatical errors
 
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Inspections

Ecxellent post George. I think it should be required reading for anyone nearing completion.

My DAR was a "paperwork" man. He barely glanced at the airplane! I'm lucky, I have a good friend who is an A&P with Inspection Authorization that provided the unbiased second set of eyes to go over my plane.
 
GASCOLATOR

Hi, It seems gascolator is required in Canada. Running a fuel injected engine with gascolator after the high pressure electric fuel pump and before the mechanical fuel pump.
What is the issue? Seems a few are running like that.
Cheers and thanks in advance for the education.
Guy
C-GUYW
RV7A Forever finishing but getting closer
 
Thanks

for the post, George. I am hoping to be inspected in the next couple of months and every checklist I can find is a useful bit of information that makes me look twice (or more)!

greg
 
gascolator

I have seen standard gascolators, off gravity feed systems, installed. This gascolator is not designed for the 25-30 psi working pressure of the injected system. They will work before the pumps, not after any pump.

This the reason behind thinking things through. Be extra carefull.

George Meketa
 
Also, double-check all fuel and oil systems FWF and use inspection lacquer on them after they're torqued.
 
Great post george

I have seen standard gascolators, off gravity feed systems, installed. This gascolator is not designed for the 25-30 psi working pressure of the injected system. They will work before the pumps, not after any pump.

This the reason behind thinking things through. Be extra carefull.

George Meketa

I agree with almost everything and I still have not drilled a hole in my FF intake plenum!..I promise next oil change I will.

I did talk to Mattituck about the sniffle valve and they said it really wasn't necessary..Maybe because I was fuel injected?

I also spoke to the Vendor of the Gascoltaor and they said it was designed to work up to 70psi (vague memory) and it would very perfectly well after my electric fuel pumps.
I ended up not using the Gascolator, but the supplier was very happy with my intentions (two electric and no mechanical fuel pump) at the time.

Other than that a great checklist..Thanks

Frank
 
Frank

Obviously you did your gascolator research, but they are not all the same. Others have installed ones that were incorrect for the application. I did not say that one should not deviate from the plans. As far as fuel systems go, I will repeat. WATCH OUT FOR CHANGES TO THE PLANS.

Sniffle valves are used, as far as my limited knowledge knows, on fuel injected engines. They are designed to allow fuel sitting in the bottom of the intake to leak out with the engine not running. This is to prevent hydraulic locking and possible damage to the motor if a large amount of fuel is pooled in the sump. Do whatever works for you.

My post was not directed at you personally. All the items mentioned were from actual inspections or from problems that caused inflight instances on other planes.

Every post I write reminds me why I keep to myself.

George
RV8
 
George

My English "Bluntness" does not sometimes translate well into "American"..:)

I really did think your post was very good, I didn't take it as pointed at me in any way. I was just providing an alternative viewpont on a couple of items.

So please keep your posts coming. My challenging of your ideas was simply intended as healthy debate, no more no less.

My appologies for coming across otherwise.

Frank
 
good stuff...

Thanks for posting your findings George. I have seen some of the things that you describe on planes that I am working on so your post sounds familliar. Both are flying planes with over one hundred hours on them!! I should say that both are plans-built non RV's but the same issues are here as well and I think aren't confined to the RV world.

"After assisting an area tech inspecter on many pre DAR inspections it has become clear that there are rules in construction that are not followed by many builders. A large area of knowledge is unknown, not being picked up or taught. This information is not in the plans, directions and publications used by builders. Many of these items are common sense, but errors repeatedly show up."

The issues with things not done properly has to originate somewhere and you are on the right track. Information on assembly and rigging of flight controls as well as engine controls may not be in the builders manual of some homebuilts. Some manuals are better than others and all are better than the head scratching that comes with a plans-built type where info on turning an airframe into a finished airplane may be non existent. The resources available for the builder of any type of airplane are far better and easier to access than just a few years ago. The maintenance manuals of some certified planes can be used for a reference in certain situations. The information on engine run up procedures and parameters for instance.
In the past things were not as good as they are today with all the quickbuild options as you mentioned. A lot of things are done for the builder and the opportunity to make errors is eliminated.
As you said watch for plans changes. I think some issues originate from changes undertaken by the builder of plans built planes. Changing from a cable operated control to a pushrod system is one example I have seen. Others are revisions to the plans that are not incorporated into flying planes.
There is no substitute for inspection be it pre-flight, pre-purchase or annual condition.

"Have a tech inspector that is very knowledgable in RV's or several good builders in the area inspect the plane before first flight."

Absolutely! A thorough inspection by a qualified person or persons is one good way to catch things. But, I hear some people saying, who is qualified to inspect my plane?? I think an EAA Tech Counselor is a start but if one is not available an A+P (Canadian AME) or other builder of the type would be qualified but don't just stop with one person the more eyes looking at it the better the chance to catch a problem.
The RV community has many "repeat offenders" and that is a great part of building an RV, the wealth of experience to draw upon.
I see inspections as something not to fear but to encourage as it can only lead to a better built airplane and a safer one too.
Phil
 
Great post!

Thanks for a great post!

My final inspection is scheduled for next Thursday (the 10th of July) and now I've time enough to go through everything once more with your checklist in hand.
 
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