Tanzman Report

What follows on this page is an account of honorary ISPA member Arnie Tanzman and his Seawind. The content of this page is almost entirely written by Mike Bowes (some text from Jody Bowes as well). We are all indebted to Mike for making this information available in such interesting and thorough detail. We are indebted to Arnie for the lessons that he leaves with us, in a way that defies description. Perhaps the best and only way we can all repay Arnie is to ensure that no one else falls victim to such a horrible tragedy. Please also see the article about oxygen deficient atmospheres in the library on this site.

Arnie Tanzman's N711AT First Flight in Sarasota | October 5, 2000

At 1:45 pm Thursday afternoon, retired American Airlines captain Arnie Tanzman's brand new Seawind launched off Runway 32 at Sarasota and headed out over the Intracoastal Waterway at 1000'. Pilot Mike Bowes flew N711AT for the next 1.1 hours in the vicinity of SRQ staying over watercourses as a precautionary measure. Arnie flew the airplane during part the flight doing steep turns and checking the effects of raising and lowering gear and flaps.

It was a 90 degree F day and oil temperature was steady at 193 during the cruising part of the flight. The pilots noted an indicated airspeed of 165 mph at 24 squared. Once trimmed out, the aircraft exhibited no tendency to roll or otherwise. Another hands-off flyer from the word go! This is the eighth Seawind to emerge from Bowes' builder assistance center. Arnie did much of the work himself and deserves full credit for a beautiful job.

The aircraft features a freshly overhauled 10-540 by Zephyr Engines, freshly overhauled Hartzell 3- blade by Santa Monica Propeller, a full UPS Technologies Apollo stack (as seen on the back cover page of Trade-a-Plane), a one-piece instrument panel crafted by Steve (Ultimate Arrow) Ryan and fabric interior by Chris Lovegrove at Mod Works. High gloss Sikkens automotive paint graces the exterior, done by Dennis Brunton in the Bowes facility. This Seawind is stunning in its all-over white with navy and gray trim striping. This aircraft was built "by the book" and initial impressions are that it is a superb flyer. One of Arnie's first comments as he took the controls was, "I'm going to love flying this airplane."

The following is from Mike's ISPA post #126 on December 16, 2001.

Members, and all of the Seawind community, we have lost a great friend and fellow aviator. It is with profound sadness that I must relay to you that Arnie [Tanzman] passed away on Thursday, December 13th (Stateline, NV) while working inside the aft tail cone of N711AT. He was in the process of changing out the Mallory fuel boost pump, which had seized after about 200 hours airtime service, and was evidently overcome by the fumes of avgas displacing breathable oxygen.

Also see oxygen deficient atmospheres

Any time that you crack open the fuel system of an in-service airplane, you will get a fuel spill. He was working by himself and nobody was there to monitor his well-being. Alas, it seems likely that many hours had elapsed before his body was discovered. Our hearts go out to his wife, Linda, who made the drive down mountainous roads, in the dark, to find him and attempted mouth-to mouth resuscitation in a vain attempt to revive him.

It may now seem that I am pointing out the obvious, but please be aware that fuel vapors, in a confined area like the tail cone, can be deadly. It would now seem that the rule should be never work on a fuel system that contains avgas, alone. This should be incorporated into the text of the build manual as a WARNING!

Arnie was a delightful and very healthy man, recently retired from American Airlines. If this can happen to him, it means it could, just as easily, happen to any of us. And it doesn't matter what kind of vehicle you are working on. Fuel vapors are heavy, they can "pool" in a confined area and they are deadly, if concentrated enough. Please be aware and be careful....and don't work alone on an active fuel system, no matter how convenient you may think it to be.

Arnie and Linda have paid the ultimate price, let us all learn from this. [ ]

May 23, 2002. Forced landing of N711AT. An account from the ISPA discussion group, post #176, dated May 27, 2002, by Mike Bowes:

I've been busy. Flying my own N369JB...she has 23 pleasurable hours on the tach, now.

Just spent all of last week out in Minden, Nevada. My mission was to make Linda Tanzman's N711AT airworthy, which included a much-needed annual inspection, and ferry the airplane back to Sarasota where it will be available for show and demonstration flight to a serious prospective buyer.

I was ably assisted by A&P and pilot, Larry Mansberger, who operates a maintenance facility on Minden airport and is a Lake Bucaneer owner and frequent flyer. From noon on Saturday, until 3pm last Thursday, the two of us worked full days on the airplane (an estimated 200 hours) whipping it into shape so that an annual could be signed off. (There had been no inspection since the aircraft first started flying in October of 2000.) The plane has 171 hours on the tach.

Finally, after numerous ground runs of the engine and a lot of other work that I won't go into, here, the Seawind was ready for a test flight on Thursday afternoon. I had 60 gallons of gas in the mains, Larry (thank God) as my co-pilot and guide, and I intended to take her up for a one and a half or two hour flight. This was Larry's first ride in a Seawind. I was counseled that I would not see the usual sea-level take-off and climb-out performance that I am used to and to expect something less. Minden sits at 4700' and with the current temperature our effective density altitude was 5800'.

The engine was running smoothly, somewhat leaned, mags checked fine, I cycled the prop once at 2000 rpm, boost pump on, DG set, transponder on ALT, and we were rolling down Runway 34, a 7000' paved, lighted runway. Acceleration was slower than usual, but didn't seem too radically bad. What really started to concern me was the abnormally longer run on the ground before I could get the plane to rotate. Even after I had the nose wheel up, the aircraft continued to run along on the mains instead of becoming airborne.

My instincts were shouting "ABORT!" and the internal conflict was that I had been told to expect lackluster performance. 2660 showed on the VM1000 tach. The aircraft lifted off about 2/3rds of the way down the runway and commenced the most anemic climb I have ever been party to in a Seawind. It barely registered on the VSI, but visually it was perceptible and I selected gear up. This, of course, had the effect of marginally increasing the rate of climb. I tried bumping the flaps up a little from 25 degrees and was promptly rewarded with "that sinking feeling" and hastily reset them to 20 degrees. The engine sounded fine, but the performance was just awful. I tried minor adjustment to the mixture and that produced no meaningful effect, except that toward rich there was a barely perceptible sensation of the engine slowing. I restored that control to where it had been.

I announced to Larry that "there is something wrong.....it's really doggy" and his immediate response was "take it to the left...there are fields over there, it's all built-up straight ahead. Airspeed 75, 200 feet AGL is all I ever got, and she stopped climbing....for about 20 seconds she maintained level flight and after that commenced a slow, but visually perceptible descent.

I had less than a minute of flight time left and still the engine sounded good. Larry told me that all engine parameters were in the green and EGTs were level and normal looking. Still she was coming down. The rocky, barren, ground ahead was giving way to a patchwork of small pastures, crossed with fences and irrigation ditches and the occasional ranch and outbuildings. "Power line coming!" exclaimed Larry.....I had spotted it too, and traded precious airspeed for altitude to clear the wire. Now she was indicating 60 mph.... I HAD to let the plane go down or we would die right there. I spotted a green-looking pasture ahead, about 800 feet square ( it was the biggest in my immediate vicinity) and I had about 20 seconds of flight left and made for it. Cleared the irrigation ditch beside it, chopped the power at about 30' AGL and clipped the top of the wire fence coming in. Made a surprisingly smooth touchdown and N711AT slid to a stop in about 350 feet.

We jumped out and were amazed to see NO DAMAGE to the aircraft except for a gash in the right leading edge of the wing which was pouring out the contents of the right main tank. That was where it had hit a steel fence post at the approach end of my impromptu "runway".

The field was level, soft and grassy. A crew of volunteer firefighters, pilots from the airport, (2 and a half miles away) and a man who had a heavy equipment rental facility, nearby, converged on the scene. In less than 30 minutes, recovery of the airplane was commenced.

Canopy locked down, batteries disconnected, all fuel removed to a drum, aircraft skidded to access road using a tractor owned by the rancher, with "wing-walkers" to hold wings level. A heavy-lift forklift, with an extendable boom was used to lift the airplane over the ditch and onto a bed of hay bales placed on a flat deck, semi-trailer. The airplane was placed at a 45 degree angle so as to minimize the overhang on each side.

Lift points for the sling were front end of motor mount, YES IT CAN TAKE IT, and forward to nose gear retract mechanism hard points. Normally, when recovering an aircraft after such an event, it is often further damaged beyond repair. This remarkable crew, under our guidance, DID NOT PUT A SCRATCH ON THE AIRPLANE!!!!

It was then driven back to the hangar, lifted, gear selected down, and gently lowered onto its wheels. Total time of the flight, about 2 minutes. Total time to get her back in the hangar, about 4 hours.

Next morning Larry and I rechecked compression, timing and the plugs. The plugs really told the story. 2 minutes of full throttle, followed by a clean cut. 3 plugs were dark & sooty, the other 3 were gray with white flecks. Mixture was not consistent over all 6 cylinders. We suspect that the fuel system was fouled with water back in October during a water landing and some small amount of water remained in the system for the past 7 months while the airplane sat in storage.

This story is not finished! The entire fuel injection system is being sent out for examination, testing and overhaul. We suspect that some components have been damaged / corroded by months of exposure to moisture and contributed to an uneven fuel distribution to the injectors which we had cleaned as part of the annual.

Yes, the engine was developing a good amount of power and not running irregularly, but it was not developing all it should be. It was good enough to fool both of us...that's the danger. There was also a very slow and gradual decline in power output during the 2 minutes which rendered the aircraft flying but unable to maintain level flight. No injuries, no appreciable damage, Experimental. The FAA and NTSB declined to investigate. I received high praise from all at the scene for remaining calm, flying the airplane, and stuffing it into that little square of green. I can tell you with certainty that just one burp from that engine and I probably wouldn't be in any shape to even be writing this for you now. Arnie, himself, used to say, "I'd rather be lucky than good, any day." I leave you to draw your own conclusions. I flew my own [Seawind] for an hour and a half, yesterday. Jody was with me. Fly safely. Mike N369JB

The following is taken from a Mike Bowes letter to Dick Silva dated May 30, 2002.

Dear Dick,

It was a week ago today that I was forced to land Linda Tanzman's Seawind N711AT in a horse pasture about two and one half miles northwest of Minden Tahoe airport. This was not a case of the engine quitting or even missing...it sounded good all the way to the point where I shit it down on very short final going into the 800' by 800' field. The entire flight lasted about two minutes, never attained more than 200' AGL and airspeed was never better than 75 MPH indicated.

This engine simply wasn't developing full power, but it sounded and acted good enough that it fooled both myself and Larry Mansberger, the A&P / pilot who had worked on the airplane with me in the days prior to the flight, and accompanied me for the test flight. Neither one of us would have ever lined that airplane up on the numbers if we even suspected what was about to happen next. It was Larry's first ride in a Seawind. The images of the flight, brief as it was, the realization that this aircraft has to be put down NOW, the approach and landing are forever seared in my memory. There is no record of this for others to view. These pictures show only the amazing recovery of the airplane by a dedicated group of men who managed to return the airplane to its hangar four hours later without putting a scratch on it!

Of all the things I have ever done in my life, this is the closest I have ever come to instantaneous serious injury or worse, yet it lasted only about 120 seconds. The obstacles, fence posts, irrigation ditches, power lines, livestock sheds, homes and barns that we passed over, staggering through the air, are what could have done serious damage to the airplane and occupants. Gear up, flaps down 20 degrees, airspeed at 60 mph indicated, engine shut down, the touchdown was firm but not violent. Then the airplane simply went gliding through the grass for 350' and coasted to a stop. If I hadn't clipped a steel fencepost, coming over the approach end fence with the right wing there would have been NO DAMAGE to the aircraft save for mildly abraded paint on the bottom where it was in contact with the earth. Incredible and thankfully so, because this airplane has no hull insurance on it. The Seawind is one tough, strong airplane and Linda later told me that this was one of the reasons Arnie wanted to buy it.

The FAA and the NTSB declined to investigate. No personal injury, no appreciable damage to anything, Experimental..."thanks for the call." Larry, the A&P, is focusing his investigation on both fuel system and ignition. It is suspected that some critical part of the fuel injection system has suffered some type of damage from old water infiltration, [seven] months ago. The aircraft sat in storage all that time and the weather was freezing. There were other pilots on the scene who came out for "a look see." I received high praise for the job I did of stuffing the airplane into that seemingly impossibly small field. Arnie himself used to say "I'd rather be lucky than good, any day." I leave you to draw your own conclusions.

Kind regards,

J. M. Bowes Aviation, Inc.

Michael Bowes, President

The following is taken from a Mike Bowes letter to Dick Silva dated October 1, 2002.

Dear Dick,

In the ensuing weeks since the forced landing of N711AT south of Carson City, Nevada a great many things have happened. The FAA, from the FSDO in Reno did in fact contact me about two weeks after the incident. The inspector needed answers to some questions including my complete name and rank. As to the events of the day, he seemed quite sympathetic and tried to offer helpful suggestions. This included an observation on how badly his Volkswagen had been running the previous winter with a clogged injector.

Eventually, I also heard from the insurance company who had a "friendly questionnaire" to be completed including copies of many pages from my personal log book. Time in type, recent time in type, last BFR and copies of my medical and ATP certificate were dutifully turned in. They wanted more than the FAA. Why? To see if they could declare the flight somehow illegal, so they wouldn't have to pay a dime for anything.

Larry Mansberger the pilot / A&P who accompanied me on the first flight has been working away on the Seawind preparing it for my return later this month. He has repaired the gash in the leading edge of the right wing and repainted all that needed it including a recoat of the entire bottom of the hull. As to a "smoking gun" for the root cause of the original problem, nothing glaringly obvious, but a bunch of little things. As previously mentioned ,. the airplane had a couple of dunkings in lakes in Texas and California the previous summer. Evidently the pilot's efforts to balance fuel load on the water had an undesirable side effect of distributing lake water throughout the fuel system.

Water originally came into the aux-tank through the air vent on the underside of the wingtip. Months later, after a Nevada winter, Larry and I found an estimated 10 gallons of water still in the left sponson, testament to how deeply buried the wing was. Every part of the fuel system showed evidence of water contamination and corrosion. The entire engine fuel injection system has been sent out and overhauled. The AC engine driven [fuel] pump has been replaced, as has the Mallory fuel pressure regulator. The latter showed evidence of fuel stains on the two pipe thread plugs. If fuel can get out, it is likely that air can get in. Even a small amount of air getting into the system can greatly disturb the operation of these injected engines. They continue to run...they just don't run right.

Larry has done a series of full power static run-ups on the engine and reports that it is making strong, consistent horsepower now. We did run-ups to about 2100 rpm after the annual inspection and before the flight. I admit the need tot do a full power run-up escaped us at the time. Neither one of us will ever make that mistake again. Athe that time, too, we did not realize the full extent of the water infiltration and the random damage caused by it. The conclusion of the story is expected to be an account of flying N711AT back to Florida where it will be offered for sale at Sarasota. The planned route will take us by magnificent Lake Powell where a photo session is planned.

Kind regards,

J. M. Bowes Aviation, Inc.

Michael Bowes, President

The following is from Jody Bowes' ISPA post #286 on October 28, 2002.

Hi everyone, well, for any of you that know what Mike are into now, I will give you an update.

We left Tampa a week ago tomorrow commercially headed for Minden Nevada to pick N711AT up to bring back to Sarasota to sell for Arnie's widow [Linda Tanzman]. After 2 days of work, she was ready to fly, we took off in severe clear and about 40 degrees temp and positive attitudes. About 50 miles from the airport at about 9500 altitude, with mountains all around us in every direction, we both felt a not normal vibration. I looked over at my very handsome, cool headed husband and for the 2nd time in our 10 yr. marriage he didn't look so cool, in fact he looked like something was very wrong, so of course I said in a not so cool tone, is some thing wrong. He said something is very wrong, the #3 cylinder on the vision Microsystems is reading 666 degrees and my (Jody) job all of a sudden was to watch the oil pressure and oil temp.

We were losing oil pressure, so of course we thought we were losing oil, not a good thing especially if you saw where we were. I called our ground support from my cell phone, not legal I know but at this moment I didn't give a rats butt. In minutes we not only had ground support but our nice new friends were in the air in their lake amphibian. I said we are headed back to Minden if we can make it, but if we can't Mike is looking for a good place to put her down.

Well, obviously we made it and when we got back and un-cowled her, we found that one of the spark plugs was finger loose which would pass enough air (gas) , heat to the temp probe that is just on the other side of that spark plug sending it to the vision Microsystems read out on the instrument panel. They did compression checks on all of the cylinders, checked all of the spark plugs looked through the bore scope and everything looked a okay.

The mechanic with the egg on his face finally agreed that the loose spark plug was the problem. He felt badly and we lost another day of flying, oh well, time to spare, go by air! We left the next morning which was Saturday, made as far as Tucumcari New Mexico, which was great because we were finally out of those dog gone mountains! I love sea level! So does this airplane!

We are now in Springdale Arkansas and for all of you that are wanting to put a auto pilot in your seawind, this is the acid test at work. They are installing a brand new trutrak auto pilot and yaw damper in this airplane. It had the trutrak auto pilot in it but it never worked, Arnie promised to bring it here a year ago so that they could get it to work properly, but as you know he died in December and that never happened.

They are positive that this auto pilot is the way to go for this airplane (the Seawind) and that all the others are light-years behind them. Jim Younkin worked as an engineer for century and for s-tec and boy does he know his stuff and what a nice person. His staff is wonderful and well, they have been waiting for us to get this plane here since may so they can get a seawind with a working auto pilot in it.

We hope to leave tomorrow, even if they were finished with it today we couldn't leave because of fog, but the weather will be what the weather will be. I am still recuperating with my back surgery so I would be off anyway. I am better off flying then I am at home now that i am feeling better, I would get in trouble at home I'm sure.

This plane flies so smoothly, and we have been flying at about 9500 not only because altitude is our friend in case of a problem but we had quite the push up there, cruising at about 160-170 ground speed. Well, that's all for now. Can't wait to get back and fly in our own airplane at sea level! We should be home by tomorrow or wed. check out our new website, it needs some polishing, but let us know what you think! Jody Bowes

The following is from Jody's ISPA post #299 on October 28, 2002.

Yep, its true we have arrived safely at Sarasota with N711AT and happy to be here. the weather held us up in Arkansas, which wasn't such a bad deal, trutrak autopilot's facilities were quite comfortable and we (I) learned so much about the auto pilot, just ask me! Weather hung us up in MS. for a couple of days and then Alabama for another couple of days, but we found this really neat place called Eufaula that was a great place to get weathered in.

Anyway, the plane performed very well, and with a few minor adjustments she will be nearly as perfect as 369jb! which by the way was taken out of the t-hangar and flown for 1.3 hours today and happy to be out and about, we had a beautiful day down here in Florida and the flight was wonderful. I will let mike give you the p-i-c version of the flight and how he really feels about the trutrak autopilot and their crew. Glad to be here! Jody Bowes

The following is from Mike's ISPA post #302 on October 28, 2002.

The indications to the pilot in the cockpit during flight (N711AT in Nevada) were the onset of a slight vibration, followed by cylinder head temp climbing dramatically in the space of a few minutes. A clogged injector was my first thought, adjusting the mixture rich made seemingly no difference to this cylinder, but made the other 5 go almost flat-line.

Anyway, we made it back to Minden-Tahoe, following highways, and proceeded to investigate the problem with # 3. Larry Mansberger conducted a compression test, peered into the cylinder with a bore-scope, pulled the rocker cover and observed the valves operating correctly. The only thing found amiss was the lower sparkplug was only finger-tight when first examined.

We fully expected the worst. A call to Charlie Melot, back in Florida, confirmed that any excursion of temperature into the 600 degree range would, at least, take the temper out of the rings and likely cause scuffing of cylinder and piston. He had a complete cylinder assembly on the way to us immediately by next day air.

The more we looked, however, the more we could see nothing wrong. Then Larry came to the final conclusion which proved to be right.

Thank heaven it was the bottom plug! A loose top plug would have given little indication until it finally blew out. The CHT probe is only about an inch away from the lower spark plug hole. The hot leaking gasses were superheating the metal around the hole and heating the CHT probe as well. The high temp reading was correct, but it was only a result of leaking combustion gasses.

We put it back together, cowled it up, and I went out and flew it to 11,000 feet for an hour. Our theory was correct....no more problem. I learned about flying from that. JMB N369JB

The following is from Mike's ISPA post #305 on October 29, 2002.

Upon arriving at Jim Younkin and Chuck Bilbe's Trutrak autopilot skunk-works in Arkansas, I made it no secret that I came with a whopping big prejudice regarding autopilots in Seawinds, in general. For years now, I have seen folks spend lots of time and money trying to get an S-Tec or something else to work properly and they never (really) do. I have coached my builders to, yes, go ahead and install oversized hatches in the aft floor to facilitate the future installation of an autopilot. AT SUCH TIME THAT WE MIGHT EVER FIND ONE THAT WORKS PROPERLY, RIGHT OUT OF THE BOX.

Jim, an autopilot designer for more than 30 years, calmly informed me that I would be a believer, before I left for Sarasota. 3 days in Arkansas has forever changed the course of history regarding autopilots in Seawinds. I have come away, not only a believer, but also a Trutrak Flight Systems Dealer and installer, to boot. Multiple test flights in N711AT, hardware changes, software changes, very subtle changes, major changes in the installation philosophy of the servos for roll, pitch and yaw, too. Believe me, none of it has been done this way before and it works well!

Jim and Chuck deserve full credit for this breakthrough and the others, well, they can only try to copy. And no doubt will. Details of the new hardware and installation technique will shortly be available on the bowesaviation.com website. Pictures are out for development now. Anyone who desires to have a Trutrak autopilot, call me. I'm selling them.

The Tanzman Seawind has a "full-house", top-of-the-line, Trutrak autopilot installed that flies the airplane better than I can, has a yaw damper that improves the ride in turbulence, offers vertical nav functions and derives its heading reference from the GPS receiver. It also has a built-in magnetic reference back-up. All at a price that beats the competition silly because Trutrak autopilots are only available and marketed to the Experimental set. This means R&D dollars are actually spent on R&D, not on jumping through the hoops of FAA certification.

This is digital equipment and offers accuracy and the ability to rapidly customize features and responses that S-Tec and Century, for example, cannot match. Younkin claims they (the competition) don't have this technology available in the market at present, but it is only a matter of time before they will be copying.

Meantime, Trutrak leads the pack in terms of features and performance for the $ spent on autopilot equipment. I think you catch my drift.

After Springdale, we were chasing a massive, almost stationary, front that we kept catching up to. Next night was in Meridian, Mississippi. Came in with 1000 and 3, barely. Next morning the clouds were on the trees and the media was in a frenzy about a tree stump being removed from a backyard in Tacoma. By midday, the beacon had stopped rotating, but all IFR ceilings were reported ahead. We ran the gauntlet under a low but well-defined ceiling, from Meridian to a wonderful little place called Eufaula, Alabama. A non-towered airport might be handy in the morning, I thought. Even worse weather was exploding behind us, coming out of Texas and forecast to overtake us within 24 hours. (I've flown in a lot of crap in my time and this was more of it.)

Next day, carbon copy, low overcast, sort of misty, 2 to 3 miles and ceiling well- defined. Again, I waited until the heat of the day was upon us, launched, and had an "orientation run" down the length of Lake Eufaula at about 300'. There was a bass fishing derby underway and the lake was dotted with high-powered bass boats. The fishermen cordially waved us on our way as we streaked by them. At least, I think that's what they were doing. It's a long lake oriented north-south. Beyond the south end of the lake, a run of river and then 100 miles of new-growth pine forest on land as flat as pee on a platter. Pulp forest, crossed now and then by a gravel logging road. Otherwise desolate.

Jody and I kept a sharp watch for microwave towers and the big Lycoming ran strong and true. The entire run was 400' agl but we knew there was better weather to the south. The entire trip from Eufaula to Sarasota is about a two and a half hour run. The final hour was flown under blue sky at 1500' over the Gulf. We had a headwind from the time we had left Springdale, AR.

For those of you who enjoy such things, I share these times with you, taken from the logbook: Minden/Tahoe - Kingman, AZ 2.2 hours Kingman - Tucumcari, NM 4.0 hours (I confess there was a little circling around Sedona area) Tucumcari - Springdale, AR 3.6 hours Springdale-local test flights totaled 2.8 hours Springdale - Meridian, Ms 3.1 hours Meridian - Eufaula, AL 1.9 hours Eufaula - Sarasota, FL 2.7 hours.

A long but enjoyable trip in a great airplane. People have asked me if, under the same circumstances, would I do it again? The answer........absolutely, especially knowing what I know now. Keep the shiny side up, Mike N369JB