The International Cessna^® 170 Association

I had an interesting trip today in my 52 B model...almost five hours of solid IMC. Since most of you probably have more sense than to do this, I thought I'd share some of my experience and ideas about the 170 as an instrument airplane and it's limitations as one.

The machine: 1952 170B, N8143A...semi-famous survivor of a mid-air collision with a Continental DC-3 in 1956 (as mentioned in a few aviation history books.) Stock C-145 and standard prop. One KX-155 with VOR/glideslope, with an ICOM handheld with an external antennae as backup. Apollo GX-55 panel mounted GPS, IFR certified enroute and terminal. No autopilot or marker beacon reciever. Narco AT-150 transponder with encoder... that's it for the avionics! Heated pitot tube and venturi driven gyros-a fairly new RC Allen attitude indicator, a Standard Precision full-face DG with a 1969 overhaul date on the case (it works great) and your standard electric turn and bank as backup (the dog house kind; I hate turn coordinators.) Oh yes, and a JASCO 50 amp alternator. Better equipped than many 170s I think, but no Bonanza.

The pilot: some middle-aged guy with 30 years experience and 16,000 hours, mostly on airplanes with many motors and pilots, but around 5,000 in GA aircraft, including 350 in 170s. Current and fully qualified, at least in theory.

The mission: a 187 nm cross country from Rock Hill, SC to Greenville, NC and return.

The weather: Solid clouds, with bases at 800 to 1,500 feet all the way, visibilities from 3 to 10 miles, light to occasionally moderate rain. The freezing level is 12,000, and so are the cloud tops. Ideal single-engine IFR,
if you feel comfortable doing that in the first place! The downside: 30 to 40 knot headwinds from about 2,000 to the stratosphere...well, it may as well be for 43A.

We launch into a 800 foot ceiling and light rain, and turn on course. Charlotte Departure clears us to 3,000 feet...once level I make the mistake of checking the groundspeed. Yikes...70 knots! I had filed for 5,000 but another airplane indicates it's even worse up there. So I request 3,000 all the way to Greenville. No problem, the terrain is flat as a pancake and there is full radar coverage, even at that altitude.

Observation one: At 105 knots TAS, a big headwind has a huge effect on your groundspeed, to state the obvious. It turned a 1 + 45 flight into a 2 + 45 one. If Greenville was near minimums (it wasn't) I would have had to re-think the alternate. As it was, I kept close tabs on the weather at airports along the way by listening to the respective ASOS/AWOS. If PGV had dropped close to minimums, I would have landed for fuel. The 170s speed and range is quite a restriction under these conditions.

After a turn in the hold at the outer marker, I shoot the ILS 20 at PGV, breakout at about 900 feet and circle to land on runway 2, since the wind is 030 at 15, another no brainer. It's raining, viz about three miles. A Cessna 421 is waiting at the runway end for an IFR release, pending our arrival and I'm expecting some kind of remark about Cessna 170s flying around in these conditions, but the radio is quiet as I taxi to the ramp. Leg one is accomplished!

Top it off, check the oil and let's get out of here! A quick call to flight service to check the weather ( it didn't change) and we are off!

On takeoffs into IMC with venturi driven gyros...if you are setup correctly, I don't see any problem. My limits - a 500 foot ceiling and at least one mile. Both my AI and DG are working fine by the time I break ground at 60 MPH, the suction gauge showing about 3.5 hg. If you fly IFR in your 170, PLEASE have the best setup possible - two venturis, or one so-called "super" nine inch venturi like I have. There has been much discussion about this on the boards. It is a simple, reliable system, and I prefer it to ANY vacuum pump setup on my airplane!

Now the fun part...in solid clouds again - at 4,000 feet the ground speed is 145 knots! Like having an early model Bonanza. I had filed for 6,000, but I was happy with 40 knots on the tail, so I stayed at 4,000. That's more like it! With the Apollo GPS moving map display, this is a long way from the first 170 I flew, back in 1974. It is the only way to fly, especially in the clouds. I don't miss not having DME or ADF, and there isn't the panel space for them anyway. The GX-55 is not approach certified, but I can live with that.

Observation two: IMHO, the 170 is not the most steady IFR platform around. In pitch it is very settled; once trimmed it is easy to hold altitude. Roll is another matter...it is work to hold a heading, especially in turbulence. In smooth air I can stay the course with rudder alone, hands off. My airplane is rigged as well as anything I have ever flown, as evidenced by it's consistent 105 knot TAS, but it always wants to wander off one way or the other. Or maybe it's too many years for me behind an autopilot! At any rate, if I made a habit of this I would certainly install a wing leveller like the Century 1. Or buy a Bonanza or 310...someday.

Are we there yet? The day of hand flying IFR adventure is nearing the end. Cleared by Charlotte approach for the ILS 2 at Rock Hill...the weather is 500 and 5 miles. The configuration for an ILS is about 1,600 to 2,000 RPM, (depending on headwind), no flaps of course, for an approach speed of 100 mph. This also yields about 4.5 hg on the suction gauge, to keep them gyros spinnin. The outstanding over the nose viz gave a great view of the approach lights and runway as we popped out of the clouds. (if there is one thing an airline pilot is good at, it's an ILS!) Stay on the glide slope, power back, drop the flaps to 20 degrees and make one of my patented wheel landings. Mission accomplished!

I hand flew almost five hours solid IMC today; never saw the ground except for the take-offs and landings. I suppose I should mention that my airplane has the stock 1952 instrument panel, with gauges strung out from one side to the other. I'm used to it; like a kind of Gestalt experience, but I know it would bother some people.

Like other light single-engine airplanes, the 170 has it's limits as an IFR machine, but with proper equipment, conservative planning (NO icing, heavy convective weather or extreme headwinds) can be safely flown IFR.
For those of you out there just getting your instrument ticket, or low on actual instrument time, please keep it conservative - ease into flying your airplane in the clouds a little at a time. I worked my tail off today...didn't even plug in the CD player, I was so busy!

A few more comments. I have noticed after flying through light to moderate rain that occasionally my static intruments would jump, then settle down. In the clouds, I fly with the pitot heat on, even with temps well above freezing. I also installed the plastic sump bottle from Cessna above the static port. Much better than it used to be, but I'm open for suggestions...perhaps an alternate static source wouldn't be a bad idea.
Also, I have noticed water in the fuel after draining the wing sumps, after flight in the rain. I guess it is getting in the tanks through the fuel vent over the cabin. More seems to accumulate in the left tank, never more than about one half inch in the standard fuel tester. It never makes it to the main sump on the firewall. I don't like it, but I don't think anything can be done. I never heard of this being a problem, but....

Anyway, I enjoyed my trip today and just wanted to share it with you guys and gals. It was the most actual IFR hand flying I've done since the 1970s! Russ Farris

Thanks Russ! You wrote a very useful, interesting, educational, and enjoyable story. I will eventually get my IFR ticket and this information is very very helpful. Monday was my Grandmother's 90th birthday and 1478D allowed me to fly to Ozark, Arkansas and participate in the celebration. Thankfully it was VFR, although I took off in the rain from the DFW area, and as slow as our planes are, a road trip would have been 12+ hours of hard driving vs the 5 hours of fun flying

RUSS, THERE ARE A COUPLE OF PLACES ON N'AWLINS THAT WILL GIVE YOU A ROOM, FURNISHED WITH A COUPLE OF GALS WITH WHIPS, WEARIN LEATHER, SPIKES AND CHAINS. THEY WILL TIE YOU UP WITH SOFT, SILKY ROPES AND PUMMEL YOURE A--- FOR A COUPLE OF HOURS FOR A HUNNERT DOLLARS! WHY RISK YORE LIFE FOR SUCH CHEEP THRILLS WHEN YOU CAN GET THESE HURT BUMPS FRUM BEAUTIFUL WIMMEN FER LOTS LESS MONEY, AND MAYBE STAY ALIVE?

How in the H--- does one make a serious post after OLE 'GAR??

Anyways.....
Russ, you hit the nail ON THE HEAD!
I've flown my '53 B-model in similar conditions and can testify that it is a real challenge, even for one accustomed to flying IFR on a regular basis professionally, to call it a pleasure flying a 170 in solid, IFR, with a bit of turbulence.
One of the contributing factors is the very light and responsive controls, especially in roll (although in serious turbulence, pitch can also work you fairly hard.) Another challenge is the orginal panel.
Mine is a later design, but it still has the large AN gyros with the Attitude over to the right. This is the worst situation imaginable from the perspective of spatial disorientation, as your inner ear is at it's worst position when facing right while traveling forward with pitching moments. (This is the scenario that the Mo. gov's son had to face while flying that twin-Cessna with failed pilot's gyro.)
It is especially difficult to detect a turn away from desired heading while facing slightly right, and it is "vertigo" inducing to turn one's head from right to left while travelling forward.
(Ever see a Barry-chair demo of this? An experienced pilot, with his eyes closed, head turned to the right, slightly head down, sitting in a chair that is very, very slowly spinning to the right in order to impart fluid movement in his inner ear. A large, plain school-room clock with large black hands & numbers and white face is at the rear of the room on the wall. It is set at exactly 3 O'clock. When the operator stops the chair from rotating at the point where the subject is facing the simple clock (a very familiar instrument, no?) and asks the subject to tell us the time,...the pilot almost falls out of the chair due to imbalance, and makes an obviously strenuous effort to study that clock, and for at least a minute is completely unable to decipher the time! It's a real wake up call to spatial disorientation.)
Even tho' I've got thousands of hours hand flying solid IFR, I still sometimes swear at myself for doing it again THIS time when I'm in solid cloud, maybe some rain, turbulence, and still trying to climb out of 9,000 feet at only 150 fpm!
Thanks for the well-written story, Russ.

P.S.- I thought that a radio aerial was called an antenna, and that an insect's "feelers" to avoid/test for objects was antennae. Does this mean N8143A has now been equipped to find those DC-3's prior to striking them?

Russ and guys/girls, wow!, that is what i thought of the solid IFR flying story. Now explainig a little more, im really impressed and glad that the people that belongs to this group, from the little experienced as i am and the pilots with thousand of hours in different birds, tell everything with such detail, patience and, hopefully, with the "MISTERIOMETER" absolutely disassembled. Not like most of pilots here in argentina who say that IFR flying is really too dificult (except for them, laff) or mechanics that explain engines in magical ways , etc, etc, etc. Hope to meet you if i go to the states some day, and invite you all to meet me if you came to argentina to eat a good asado!!! and get a flight in the virtually free argentintian airspace, managed by condors and eagles. My best regards to you all and please add me if you have instant messenger like yahoo, i really enjoy chatting with foreign pilots.

Excellent message, Russ ! IFR flying really makes the airplane useful.
These days there's a minefield of restricted airspace and often marginal VFR wx. I usually go IFR here on the east coast. But not usually hard IFR.
My airplane's equipped similar to yours but without the IFR-approved GPS, just a Garmin 295 with external antenna. I do have a marker beacon. And the dual venturis work just fine. I hope to have a heated pitot soon- just sent Velvet $15 for the Cessna drawing.
As for newly IFR-rated pilots- go easy on the weather, set realistic minimums. Get practice by filing IFR in good weather. Practice those approaches often.
IFR without an auto-pilot or co-pilot is work. But I think it's easier in a 170 than in almost any other airplane.
Rudy

Russ, great story. As a "glass crippled" airline type I have avoided putting gyros in the ole 170 so as not to get tempted to fly single engine IFR again.
Now I have decided to bite the bullet and get equiped for at least some limited IFR.
Question - do you have a single "super venturi" or dual, and are you using a regulator? How is the vacuum at say 80 kts vs. 100kts on approach?
Karl

lowNslow wrote:Russ, great story. As a "glass crippled" airline type I have avoided putting gyros in the ole 170 so as not to get tempted to fly single engine IFR again.
Now I have decided to bite the bullet and get equiped for at least some limited IFR.
Question - do you have a single "super venturi" or dual, and are you using a regulator? How is the vacuum at say 80 kts vs. 100kts on approach?
Karl

Hi Karl...yep, I'm a "glass-crippled" airline type myself (757/767), so I feel your pain. To answer your questions, I have a single "super venturi", and yes, I do have a regulator installed. I have it adjusted to close to max
hg, about 6.0 in cruise. I might have confused everyone by mixing knots and MPH in my post; my airspeed is original and reads in MPH. The 100 I use on approach works out to 87 knots, and about 4.0 hg suction. I have flown around for 10 minutes at 60 MPH and 2.5 hg, and the gyros worked just fine. I use 100 MPH as a nice round number - it also fits into the traffic flow. Personal preference, I guess. And plenty of air for the gyros. I'm sure 80 knots would work as well. When you break out on approach, throttle back, and the speed drops quickly - two clicks to flaps 20 degrees, slow to 70 mph and you are there. Excellent view, as I'm sure you know.

If we can coax George Horn out of his shell, I'm sure he can give us his thoughts on the best venturi/gyro setup. I'm quite happy with mine, as it is. Russ Farris

I'm glad everyone enjoyed my IFR in a 170 missive, thanks. Now to all you wise guys - Ole Gar, I was on the floor convulsed with laughter when I read your post...then I made the mistake of showing it to my significant other. She was not as amused as I was...women, no sense of humor! And to George Horn - uh, I thought I knew the difference, but here's the reason for the faux pax. I watched the 1954 Sci-Fi classic film "Them!" with my son the other day, (about giant ants in New Mexico.) The old prof keeping talking about "antennae" on the ants, so it must have confused me, especially since there is a 1952 170B in the beginning of the film! Pretty good excuse, eh? Russ Farris

P.S. A 170A is also in the 1955 film, "Tarantula"...must have too much time on my hands...

russfarris wrote:I'm glad everyone enjoyed my IFR in a 170 missive, thanks. Now to all you wise guys - Ole Gar, I was on the floor convulsed with laughter when I read your post...then I made the mistake of showing it to my significant other. She was not as amused as I was...women, no sense of humor!...

Whenever I'm feeling stressed I log back on and read Ole Gar's posts. I still get stomach cramps from that last one! You know, Russ. With knowlege like he possesses of Nawlin's, you'd never guess that Ole Gar met his better half at a professhional gospel singin', when he, a member of another group, was asked to fill in for her sick tenor! (It's even more difficult to believe she kept him!)