Swift Carbon Monoxide Problems

Subj: Carbon monoxide
From: Jim Shosted <Jim2swift>
Hi Jim,
On a recent flight with my Swift my passenger and I thought we smelled the scent of exhaust. We opened the fresh air vent and that took care of it. However soon after that flight I found myself at my nearby home improvement store where I purchased a Nighthawk battery powered digital readout C O detector. It works great. I took it flying with me over the weekend and found with the cabin vents closed I had 28 PPM (parts per mill) of C O in the air. 50 PPM is max for an adult in an 8 hr period. When we opened the fresh air vent or cabin heat vent C O returned to 0. I was a little surprised since I have the tail wheel opening covered. We did find some gaps in the left wheel well to put some tape on. I never did feel good about the old C O detector disc. This unit shows you on a LCD window. If you would like to try it out in your plane let me know. Every pilot should know if they are being exposed to carbon monoxide. See you around the airport. Jim2swift.

Thanks for the explanation of the cylinder bushings. You seem to have the answers so I will ask you directly: (Editor's note: That's why we call him the "Answer Man" Steve...) I am considering installing the Temco-designed partition/bulkhead that installs in the tailcone and is supposed to stop/reduce carbon monoxide from coming into the tail wheel area and migrating to the cabin. I got a tracing of the bulkhead from Joe during the National. My question is -- how best to fasten the bulkhead to the fuselage? What material should I fabricate it of? I have been considering thin "temperboard".

For my current annual I took out the partition behind the seats, as well as a fabricated aluminum cover for the area in front of the seats (C-152) and which covers the vent lines and the emergency crank system. I have found out there are so many leak holes in the Swift that I can't possibly plug them. Fortunately, it made running my cables for the new strobe system easy! Now, if I can only find a three foot "munchkin" who is willing to do A&P work, I will have my forays in the tail cone only as bad memories (I am 6'2").

What type (make and model) of twist fasteners were used for the original inspection ports? They have a blade screw head and a pin which twists into a corresponding female receptacle riveted into the wing skin. Steve Roth <stevenroth@aol.com>

You can use duct tape or sheet metal screws to hold that draft seal in. Fabricate it out of any light cardboard or hardboard. Those fasteners are "airlocks" and I believe they have them at Swift. -- Jim

From: Jerry J. Adams <alanding@huntel.net>
Tested for Carbine Monozide on my 210 Swift, with a single collector exhaust, and tested positive. It didn't take long turning dark, about 10 minutes. I do not have a heater and think It my be coming through the tail. Is there a boot arrangement to block access, or does the false bulkhead work best? Does the single exhaust 210 more prone to this problem. The belly skins really look tight.

I would suggest installation of the bulkhead seal. I do not know if the single exhaust is more prone to this or not. (I presume this is the center exhaust from a Cessna 336) Contact Jim Shostead at: Jim2swift@aol.com -- Monty

From: Rick Stroud <Rick.Stroud@tbe.com>
Subject: Old Song-New Emphasis
I recently read an article on carbon monoxide problems in aircraft on avweb (avweb.com) under their aeromedical heading. The article was very detailed and reviewed a couple of carbon monoxide detectors. I purchased the one recommended (AIM Model 935 available from Aeromedix.com, about $79 with shipping) and found both our Swifts were pumping carbon monoxide into the cockpit. My Swift (210 HP w/bubble) peaked at 150 PPM on takeoff and Lana's Swift (145, mostly stock) peaked at around 45 PPM. Since I was headed over to Jim Thomason's for annuals for the Swifts, the first thing we did was seal the tail on both birds. That dropped the readings to 'Lo" to 5 PPM for both birds. The following table from the article indicates the levels and their effects.

35 PPM No obvious symptoms after 8 hours exposure

200 PPM Mild headache after 2 hours exposure

400 PPM Headache, nausea and dizziness after 2 hours exposure

800 PPM Headache, nausea and dizziness after 45 minutes exposure, collapse after 2 hours exposure

1000 PPM Unconsciousness after 1 hour exposure

1600 PPM Unconsciousness after 30 minutes exposure.

The article indicted that there have not been any published "tolerance level" for aircraft but that the original OHSA regulations was 35 PPM continuous in the workplace but was subsequently raised to 50 PPM. The author's recommendation for aircraft was 5 PPM - worry; 10 to 20 PPM land immediately; and 35 PPM - you have an emergency. I believe the author was a bit conservative but will readily agree that any exposure is not good.

We also checked both our birds with the heater on. Our heat muffs appear to be OK as the heater did not raise the readings for either bird. Guess the case in point is that Swifts have a known problem with airflow forward from the tail and if not sealed you are probably getting some carbon monoxide in the cockpit. Of course, that would be even worse if the exhaust stacks are leaking into the heat muff. We are planning on using the detector on all of the aircraft (even other brands!) around the home field to possibly head off problems. Now that I really know what is in the cockpit with me, I would certainly recommend checking the CO level in any aircraft (especially Swifts) with the heater both on and off. -- Rick Stroud

Subj: Tailwheel cover
From: Dennis Friedrich <dfriedri@guru.waterville.wednet.edu>
Does anyone have any drawings etc. on how to cover the tailwheel hole? Do they run a strip on the inside to fasten it...or the outside? I had a cloth piece made and spent an hour under the airplane trying to decide on just how to attach it. Am trying to make sure it is sealed tight. Thanks.

The factory installed a draft seal bulkhead made of cardboard at sta. 145.33, it was just screwed to the existing bulkhead with wood screws. If you are closing up the hole where the shock strut and steering cables exit, you are on your own. Look some Swifts over at a fly-in and you may find one to give you an idea. -- Jim

From: Larry Owen <T081763@sphn.com>
Subject: Tailwheel hole -Reply
Denis, you got me on my soapbox again (just kidding) or how I covered my tailwheel hole story #934. This may not be what Dennis Friedrich is looking at, but here is what I did. I sewed a three sided piece of heavy cloth with a vinyl type covering, (the stuff you use for sofa's). Cut to taper into a cone, with Velcro along the back seam. Sort of a upside down, three-sided pyramid. The top "hole" is big enough to over lap the skin by 1/2 inch. Bottom hole is just big enough for the tailwheel to come out. Velcro closes it up. Sewed into the inside, heavy plastic "rub guards" for the tailwheel control arms so they can not rub on the cloth. Cut a 1/2 inch ribbon of alum from some thicker stock (32?) and bent it into the shape of the skin hole. Sort of like a chrome strip for you car. Paint to match. Put the cloth between the skin and the strip. Drill small mounting holes (plan this out so not to interfere with anything !!) and assemble. I used short flat-headed sheet metal screws (sorry), but a better idea would be mounting nut-plates. The cover keeps the grime off the tailwheel. The Velcro opens in the back for inspection. The vinyl cleans easily. The color matches the swift. Never had any problems. Larry Owen N78287