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C-170B go-around manuever
Posted: Sun Aug 11, 2002 8:36 pm
by wa4jr
Closing in on 11,000 hours flying time and I have just had the most terrifying experience of my career conducting a go-around in my O-300 powered 170B at Twin Oaks Airpark in San Antonio.
I was coming in on rwy 30 with a quartering tailwind. Recommended at T94 to land on 30 even with up to 12kts tailwind due to the upslope to the NW and tall trees at the end of rwy 30. My first time into this airport which sports a 2100 foot runway in the middle of a residential/commercial area of San Antonio. I wanted to overnight my aircraft here while celebrating our 5th anniversary with my wife. What a celebration we had

In my quest to get the airplane on the runway with enough time to stop, I let it settle a bit too hard and the bouncing game started. On the third bouce it was time to get out and try it again. With 30 degrees of flaps, I almost did not get the chance to try this approach again

There was no perceptable acceleration when I gave the aircraft full throttle, and with 30 degrees flaps, there was precious little climb performance. Approaching the trees at the end of 30, I was sure we were going to settle into them and I was goind to lose my 170 along with my family. Someone upstairs was flying with us, as I was able to coax enough altitude out of the airplane to get into a shallow VEE in the trees. I flew in this VEE just inches above the treetops and rooftops at 50 MPH indicated. The trees and terrain were rising along with my meager climb. I was able to see a slight depression 10 to 15 degrees to my right and cautiously maneuvered to this depression of US281 almost creating a "fly-through" window at the Taco Cabana

After what seemed like a lifetime, I was able to get enough altitude to permit safe retraction of the flaps to 20 degrees.
I made one more approach to T94, but this time with 20 degrees as a final flap setting in anticipation of another go-around. I managed to stay away from the "pogostick" game on the second landing, but my wife said NEVER AGAIN to T94, and fortunately my 11 year old daughter slept through the entire event

Had my 2 year old been with us along with the additional weight of her car seat, we would have been in the trees.
So now I am giving up the 30 degree flap position. The pilot that checked my out in the 170 said never to use the 40 degree flap position, as a go-around maneuver would most likely not be possible. I now see the go-around maneuver from a marginal field as most likely not possible even with 30 degrees flaps in an O-300 powered ship....we were just lucky this time at T94.
I would like to hear from other 170B pilots on the use of flaps into marginal airports. Any tips other than getting rid of the O-300 in favor of the O-360...which I will be doing as a result of this adventure as soon as I can afford the swap

How about the use of the new VG kit

Posted: Mon Aug 12, 2002 1:23 am
by N1478D
Hi John,
A quartering tailwind was most likely your biggest problem. They are very hard to deal with sometimes as your tail is coming down. And, it is pushing you to the trees instead of providing lift like a headwind does. I am not sure why you were not able to reduce the flaps to relieve the drag as you applied power, but you could practice that at a more forgiving airport. Some strips would have to be treated as a land or else situation if you have to land with a tailwind. The first time in to a new place under tough conditions might warrant light load, lots of practice beforehand, etc.
Short strips require coming in low and getting it down very close to the aproach end, and a quartering tailwing makes that very difficult. After the tailwind pushes you down towards the middle of the field, a go around is just that much tougher. I am very glad you found the Vee and you and your family made it without getting hurt, but the engine in your plane will handle that strip just fine.
Posted: Mon Aug 12, 2002 4:57 am
by zero.one.victor
It's hard to say without seeing the airstrip in question,but I would generally rather land into the wind & deal with a slight downhill rollout than land with a tailwind uphill. Especially with a B's barndoor flaps,it's not too hard to really drop it in over trees at the approach end of a strip. Of course,it'as like Tuesday morning quarterbacking,it's ALL real easy if you weren't the guy out there having to do it!
Regarding the bouncing,if this was a case of porposing,I usually turn a flubbed 3 pointer into a wheel landing. Just a matter of timing when you're gonna come down for another bounce,then "sticking" the mains on with a LITTLE forward yoke. My 2 Luscombe flying buddies call this a Turnerized landing. Sometimes it's more desirable to salvage a bad landing,even if it's not pretty,than to attempt a go-around.
Anyway,you're here to tell the tale--good job!
Eric
Posted: Tue Aug 13, 2002 4:59 pm
by GAHorn
Putting my CFI-hat on here for just a moment.......
The 170B is only approved for takeoff (go-around) with 20-degrees or less flaps. Those are the only flap settings for which takeoff performance is plotted.
This means you must not attempt a takeoff or go-around with flaps setting greater than that unless you wish to play "test pilot".
The airplane may have it's flaps retracted from any position ...to any position...while inflight,....provided that you are willing to pitch up sufficiently to avoid that sinking feeling. There is no reason that the aircraft cannot have it's flaps retracted without a loss of altitude, provided that the angle of attack is increased sufficiently to make up for the subsequent loss of lift...and also provided that the minimum flaps-up stalling speed (bottom of the green arc) is met or exceeded.
In other words, as long as the IAS is 58 mph or greater (B-model), then full flaps can be reduced to Zero-flaps without a loss of altitude. So,...if you are approaching at say,...60 mph or greater with full flaps (40-degrees), and decide to go around, then full power accompanied by increased pitch which offsets flap retraction should not be a detriment to your go-around position. Remember at density altitudes above 4,000' that flaps will increase your takeoff distance. So at higher density altitudes 1) do not use flaps for takeoff or go-around unless sufficient runway exists and 2) do not approach at speeds below the Zero-flap stalling speed. Note: This should not pose a problem if the recommended techniques are used. For example, the Owner's Manual recommends a full flaps approach speed of 67 mph IAS. Since this is well above the Zero-flaps stalling speed, a go-around should not be a problem,....simply apply full power, raise the flaps while simultaneously raising the nose to maintain the 67 mph IAS (which co-incidentally is the flaps-20 obstacle-clearance or best angle-of-climb speed.) Now that the aircraft is full-power and clean, allowing it to accelerate to 76 mph will bring you to the best rate of climb.
I recommend that pilots practice this technique of flap-retraction/pitch-up at altitude until they are comfortable with the manuever and are reassured in the airplane's ability,...prior to needing it at short strips.
I also recommend that pilots not lower full flaps until a committment to a landing is made. It's important to remember that airplanes will decelerate faster on the ground than in a floating search for a smooth touchdown. When that perfect touch-down is elusive, give up on it and let it sit down hard in order to begin brake application. A fast way to do that is to suddenly retract the flaps and let 'er quit flying. Ironically, that flaps-up also gives you the best braking action.
(While on this subject, the question is sometimes asked "Will VG's help?". My personal belief is "No." VG's, by lowering stalling speeds, make the float last longer and eat up runway. They also reduce braking effectiveness by reducing weight on the wheels. The argument that VG's will lower stalling speeds and therefore shorten landing distances is offset by the reluctance of most pilots to actually fly that slowly. Remember, the fastest way to slow an airplane is with it on the ground with brakes applied. And, VG's claimed ability to allow a slightly slower full-flaps approach speed then creates an even greater disparity between approach speed and an effective obstacle climb speed. In the event of a decision to go-around, the pilot would have even more airspeed to try to make up.)
Posted: Tue Aug 13, 2002 8:47 pm
by wa4jr
Now parts of the puzzle are coming together for me

During the initial phase of the go-around, I did not feel comfortable diverting my attention from outside the cockpit to inside to fiddle with the flap handle, not to mention pitching up while the flaps were being retracted. When I retract the flaps, my body moves forward and down which really messes up my situational perspective. As I move foward with the flap handle, my tendancy would be to release backpressure on the yoke momentarily...which would not have been the right thing to do. This is indeed a maneuver to be practiced at altitude or over a long runway as I am going to find in difficult to pull back on the yoke while my body goes foward and down with the flap handle

Also a factor was my low airspeed during the go-around just over the tree tops. In addition to the settling of the aircraft due to flap retraction, I was afraid of inducing a stall. When a couple of feet of altitude loss would have put me in the trees, I did not have any safety cushion to play with even at the later stages of the go-around.
For now, until I can practice smoothly raising the flaps to 20 degrees while maintaining proper control of the aircraft, my self-imposed max landing flap setting of 20 degrees is working out quite nicely. I have found it easier to flare and don't have near the tendancy to bouce like I had at 30 degrees of flaps

Makes me feel better to hear the Enterprise car rental folks talk about how many folks they pick up from T94 have had scary experiences on the landing

Makes me really feel good to hear the airport manager tell of a C-180 that tried to get into the strip four days before I came in. Fella came in and touched on the tailwheel first, then let the mains bang on, then started boucing all over the place and almost scrape a wing before he cobbed it and the extra power of the 180 pulled him out. He did not even make a second attempt...went to SAT international to dry his pants

Thanks for the input guys

Go around
Posted: Wed Aug 14, 2002 2:09 am
by flyer170
I had to go around while on final a few days ago. I have a 170A (the fast one)

The situation goes like this, day time, long runway at 1000 ft msl, not much wind, 80deg temp, landing lights on, I'm stabilized on final about 65 mph, full flaps, 1/4 mile out from the numbers, a nose dragger that was waiting pulls out on the runway and slowly starts their take off roll. I went to full throttle and started cranking on the trim. I announced my intentions, heading etc. and climbed back into the pattern. The nose dragger acknowledged my presence and rapidly left the pattern.
Learnings for me: The practicing at altitude going to full throttle with full flaps and triming out, payed off

. Don't trust anybody, be ready for anything, we were both on the radio and I had announced all my positions. I think he had mistaken another aircraft for me and never knew I was there until I announced my go around

.
I know the flaps on my speedy A model

are not as large as the B model but expect lots of pressure on the yoke when going to full throttle with full flaps and trimed for final.
Bob
Posted: Wed Aug 14, 2002 5:46 pm
by Roesbery
Having learned to fly the 170 in a stock model ( 0300 ) with the light gear legs, working into and then out of marginal strips, learned a few things. When I am trimmed in level flight I don't tuch the trim until I'm ready to taxie on the next flight. 20 degrees will give you a good approach speed, on short final full flaps. When the last of the power is off grasp the flap handle, at the instant of tuchdown dump the flaps ( full up ) and apply brakes as needed, no bounce, maximum braking ability. On a go around or if you hit a sinker an take off and need to clear a obstacle, after breaking ground you can add full or partial flaps to gain some quick altitude, But then raise the flaps quickly but SLOWLY as you will not accelerate with the full flaps with the 145 hp engine. Some times going through several cycles to gain enough airspeed to climb out. The 180 hp does help your heart beat easier, untill you get into the tighter places. Try moving the flaps through their entire range over a long runway on take off and see what happens and you will soon know what will or won't work. And altitude and or temperature does make a big difference as to what will work.
Posted: Thu Aug 15, 2002 1:06 pm
by Rudy Mantel
Interesting and constructive discussion on flap use and go-arounds. But the main thing is to always land into the wind, never downwind,even if it's 5 knots.
(I know, never say never)
Rudy
RETRACT! RETRACT! OR 10*
Posted: Thu Aug 15, 2002 1:38 pm
by flyguy
One of the most common oversights in an 'emergency' go-around is to leave the carb heat on! You didn't state that in your explanation but it makes a "BIG" difference in available power on any day but especially on a hot summer day. A good CFI will teach a routine for doing a 'go-around that is sorta like a checklist. (We still use them don't we?) 1. Full throttle 2. Carb heat off. 3. Flaps up (carefully). 5. Announce. And always 'Fly the airplane'!
Zero One Victor said it well. A tail wind is of very little help when you have to do a go-around and desperatly trying to gain altitude and are too close to the ground. Your ground speed will make you feel like you are going fast enough to climb but air speed is less than enough to clear obstacles approaching at an alarming rate! Do the math before you approach to land at any unfamiliar airport with unusual features. Then throw in a "FUDGE FACTOR" that will err on the safe side.
(This is also a positive claim for the ten degree flap notch, George. ((speaking of "B" wings only)), The lift generated by the additional flap setting is more than the added drag component. It has been my experience, and in no way is documented in Cessna's literature, that the flaps settings of 10* and 20* are 'lift friendy' and 30* and 40* are pure drag!)
Posted: Thu Aug 15, 2002 6:42 pm
by wa4jr
Yes, the tailwind really added to my problems at T94 in San Antonio. I was led into the situation by the operational notes contained in the AOPA Airport Guide listing as well as the FlightGuide binder. I now consider a landing on rwy 30 at T94 with a tailwind to be a "box canyon" affair. The only option is to land. If I ever go there again, and my wife has said that is NOT a possibility

I will land into the wind...even if it is over tall trees with the runway sloping away as rwy 12 does...that way if I don't get her down I have a safe option in a go-around over low trees and descending terrain.
I've thought about the carb heat...and can't honestly remember if I had it pushed in or not during the go-around

I usually stick my thumb out on a go-around so that the carb heat automatically goes in as the throttle goes in...but never being so close to so many trees and houses before may have caused my thumb to white knuckle around the throttle

Practice will be in order on go-arounds when I get back to Northern VA

Posted: Thu Aug 15, 2002 7:37 pm
by N3243A
When going into strips that are short/marginal or where a go around is a real possiblity, I always push carb heat off on short final when I know I have the runway made. Having done a few go arounds with carb heat accidently on, it does make a big difference.
On a slightly related note, I witnessed a Super Cub ground loop last week at Birchwood Airport from start to finish. This poor guy attempted to land with a 7 knot tailwind with 29" tundra tires on asphalt. On touchdown, his left wing dipped low enough to graze the runway. As he veered right he went off the asphalt into the grass and started sliding. The grass was forgiving and he almost was able to keep in control. Unfortunetely as he was sliding in the grass he came up onto a interconnecting paved taxiway (at about a 45 degree angle). Those big tires "grabbed" that asphalt and the gear literally sheared right off the plane. Of course he had a major prop strike, the right wing buckled the lift struts, the fusilage is likely twisted etc. etc. The two guys were unhurt but it was pretty nasty. The final insult? The plane wasn't his. It belonged to a friend (ex-friend).
Bruce
Posted: Thu Aug 15, 2002 9:30 pm
by GAHorn
Hey, Bruce and I agree on something! Alert the media!

Seriously, Bruce's technique of using carb heat as a precaution to carb ice prior to throttle reduction, heating up the carb, and then pushing the carb-heat back off, I believe is a good one, and is what I do on every descent, and on every approach. During cruise, I note my rpm (and MP since I have that guage also). Any reduction of either guage prompts me to apply carb heat and look for an initial reduciton and any possible recovery of rpm/MP. When I'm certain I've not gotten any (or certain I've removed any), then I push carb heat back off. (Although it's possible to require continuous carb heat under severe conditions, I've personally never experienced that need. If I did, I'd consider changing cruising altitudes.) I occasionally apply carb-heat for 15 seconds about every half-hour anyway when cruising long distances, just to reassure myself. Just before starting a descent, I apply it again for 15 secs, or so as a precaution, then remove it for the descent.
When approaching the airport, I apply it on downwind (or outside the Final Approach Fix) and then fly the remainder of the approach with it off (if I've not found any during the first application. If I'd found that carb ice was present with that first application in the pattern, I'd probably fly the rest of the approach with it on until very short final.) I always remove carb-heat on short final in preparation for a go-around. (Which also ensures that any ground operations are done with filtered air, as the carb-heat bypasses the airfilter.)
Posted: Thu Aug 15, 2002 11:36 pm
by N3243A
I've contacted the Wall Street Journal, George. They will be doing a full write up on our unprecedented agreement. It will be the Front Page cover story too.

Posted: Fri Aug 16, 2002 1:04 am
by GAHorn
Watch the economic recovery
BEGIN!! 
AOPA AND DETAILS
Posted: Fri Aug 16, 2002 12:11 pm
by flyguy
Here is a site I like to research when planning a landing at a strange airport.
http://www.airnav.com/airports/
put in the airport of choice and voila'
http://www.airnav.com/airport/T94
The little picture and verbage alerts me to possible alternate operating procedures.