Oops, darn it...

salex said:

This last bit of discussion about the catastrophic loss of a control surface on the turbine float plane made me try to think about what I might do if some similar disaster occurred on my PA-11. Let's say an aileron/rudder/elevator cable breaks or comes disconnected, or a pulley/wheel falls loose, or a pivot pin falls out, or etc. Hmmm. My poor little brain was immediately tied in knots. With the elevators I did have some side thoughts to engage as regards the trim cables; but all in all, I could not get far in trying to think of alternatives for quickly developing alternative methods of control sufficient to execute a survivable crash/landing. I think I remember a story of someone having some failure of control for elevators but managed to survive with a mix of trim and throttle control. A full on discussion of such events here would occupy the next two years! But it occurs to me to wonder if anyone has ever done a full on study of these possibilities for a simple cub-styled plane and written a book about it. Anyone heard of such?

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I am familiar with two such events in small Pipers. A PA11 lost up elevator cable and was landed safely by the instructor using trim and power. This happened many years ago at what is now Bayport Aerodrome. The instructor was Tom Murphy, the most natural pilot anybody around here ever met. I swear he was part bird. Maybe Jonathan Livingston Seagull.

The second was not so good. A PA18 glider tow lost down elevator on take off with glider in tow. Pitched up, stalled and resulted in a fatality. Granted in the first case the pilot had more time to analyze the situation than the second pilot did.

Rich

Richgj3 said:

The second was not so good. A PA18 glider tow lost down elevator on take off with glider in tow. Pitched up, stalled and resulted in a fatality. Granted in the first case the pilot had more time to analyze the situation than the second pilot did.

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I have towed with several different aircraft. I alway set trim after landing so I was in trim for the next tow. Did the accident report indicate how far out of trim this tug was?

I've been reading these comments about Otters and their control systems and I would like to make an observational comment.

Most of the comments are negative, and suggest that 'someone' needs to step in and stop these 'dangerous' systems from flying. As someone that has helped maintain Otters/Beavers for the last twenty or so years, I disagree strongly. As an A&P, the first time I worked on these aircraft, I asked questions. I was taking responsibility for the airworthiness of the aircraft, so I went and talked to 'old guys' that had flown or fixed them since they were new designs. ALL of them told me to pay extra attention to the tail and landing gear. And my experience has shown that they were right. One look at the main gear struts will tell you that a broken bolt or strut stands a high possibility of punching a hole in one of the fuel tanks. Tail wheels on a heavy aircraft like these take a special beating along with the structure where they are mounted. Putting an electrical tail wheel steering assembly in an Otter tail adds a complex item to harsh environment. Then come the warnings about insuring that the rudder, horizontal, and elevators are installed correctly AND maintained properly. For installation, this means using the correct hardware and installing it in the correct order. Maintaining these items means just that; do your maintenance! Perform your 100 hour inspections and do them correctly. Do any special inspections as required and comply with your ADs. I guess I'm trying to pass on the info given to me but I'm also trying to point out that the issues we've been discussing are largely avoidable through proper maintenance. I've had to replace those loose bolts in those tabs and rod ends. I've looked for those cracks. Do I think that any of these systems are especially dangerous? Absolutely not! Every aircraft ever flown has some special area that bears extra attention. And, in this case, it requires nothing more than good maintenance practices to keep it airworthy.

We will never have a perfectly safe aircraft but we can use our heads and make them as safe as humanly possible.

Web

wireweinie said:

——- the first time I worked on these aircraft, I asked questions. I was taking responsibility for the airworthiness of the aircraft, so I went and talked to 'old guys' that had flown or fixed them since they were new designs. ——-

Web

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This right here.

Experience is the best teacher. Without it, listen to those with it.


Transmitted from my FlightPhone on fingers… [emoji849]

Seems I remember the hot rodded P-51 air racers have had trim issues also. Believe motorcycle man, Bob Hannah has a story, luckily he can tell. I recently looked over a nice 180 Super Cub glider tow plane that had horizontal tail failure--lucky was still on the runway ---glider released safely---inverted Cub ---substantial damage but very fortunate pilot. Empennage is VERY important on all aircraft. just an old geezers 2 cents

frequent_flyer said:

I have towed with several different aircraft. I alway set trim after landing so I was in trim for the next tow. Did the accident report indicate how far out of trim this tug was?

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I don’t recall if that was mentioned. I will search later. This happened twenty years ago at least at KHWV Brookhaven NY. The Cub had just come back from a recover job. Bolt and nut missing (assumes the nut was ever there.)

Richgj3 said:

Bolt and nut missing (assumes the nut was ever there.)

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This is why I never put a castle nut on without putting in the cotter pin. This even if I think I may have to remove it again. It is too easy to forget or miss an important one.

And flag anything that is only partly done with bright colored masking tape, and a notation if not obvious.

I’m new to the DHC-3 this season and learning every day. Garrett-12 on EDO 7850 floats. Observations in just under 250hrs. Amazing performance! The controls are smooth and you have to remind yourself that you are flying an 8000lb airplane because it doesn’t feel like it. If you feel a slight vibration in your feet trim the rudder. The cannon plugs for the fuel sending units loosened enough to effect the fuel quantity gauge. The cylinder release screw on my S&W 629 pistol that I carry in the airplane came loose (not aircraft related but interesting).

An old DHC-3 1340 pilot shared a story when he lost the elevator jackscrew in flight and had to have all his passenger run to the rear to maintain altitude. Was able to land safely.

I’ve had an inflight rudder failure in a Cub and was able to maneuver to a safe landing. So these Otter incidents have me very concerned very alert.

^^^^What's normal cruise speed and how close is that to maximum? Edit: Like Vno or Vne?

Gary

BC12D-4-85 said:

^^^^What's normal cruise speed and how close is that to maximum? Edit: Like Vno or Vne?

Gary

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An extremely high time Garrett Otter pilot told me once that the turbine has little effect on 'forward' speeds but makes a huge increase in climbing speeds. Makes sense as the design of the wings and airframe will set airspeeds no matter how much horsepower is under the cowl.

Web

wireweinie said:

An extremely high time Garrett Otter pilot told me once that the turbine has little effect on 'forward' speeds but makes a huge increase in climbing speeds. Makes sense as the design of the wings and airframe will set airspeeds no matter how much horsepower is under the cowl.

Web

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Web, here's why I ask about airspeed> https://data.ntsb.gov/Docket/?NTSBNumber=ANC15LA037

Read the three Docket files for their analysis.

Gary

My point is that the limits like Vne are dictated by the airframe, not the engine. Now if someone exceeded an airspeed limit, then damage is probably going to occur.

Web

Web, yes I agree. Which is why above I asked Yetnacruiser what indicated and true airspeeds were experienced during normal ops, and in what configuration?

Gary

frequent_flyer said:

I have towed with several different aircraft. I alway set trim after landing so I was in trim for the next tow. Did the accident report indicate how far out of trim this tug was?

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I found the report. It happened in May of 1984. Funny how time flys as we get older. . Not much detail. No mention of trim position. PIC did not have a current BFR and was fairly low time. But that’s not what killed him. The airplane got re-covered and its annual inspection 30 hours before by the same shop. They were assigned the bulk of the responsibility.

They found the bolt but never found a nut or cotter pin.

Good advice to set the trim.

wireweinie said:

My point is that the limits like Vne are dictated by the airframe, not the engine. Now if someone exceeded an airspeed limit, then damage is probably going to occur.

Web

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Web,
Not sure about the Otter, but when DH converted to the Turbo Beaver, they were required to reduce Vne to the top of the “normal operating range”. That eliminated the yellow arc, which turbines don’t have. Vne on a recon Beaver is quite a bit higher than a Turbo Beaver. At least the DHC-2 MK 3s that came out of the factory.

MTV

If readers do nothing else at least read the "Aircraft Performance Study" linked in #3022 and #3046. Note the difference between the calculated Calibrated and True Airspeeds. Then ask yourself which one the airframe is most affected by?

Gary

BC12D-4-85 said:

INote the difference between the calculated Calibrated and True Airspeeds. Then ask yourself which one the airframe is most affected by?

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I think the answer is EAS (equivalent air speed) but few aircraft display EAS. Many aircraft do have Vmo reduced at increasing altitude to take account of the increasing difference beween CAS and EAS. This Vmo vs altitude table may be included in the TCDS and may also be required to be placarded on the instrument panel.

One more question: At any time during flight - takeoff to landing - can propeller blown air over the empennage exceed V-limited airspeed that's sensed by the pitot-static system?

Gary

BC12D-4-85 said:

One more question: At any time during flight - takeoff to landing - can propeller blown air over the empennage exceed V-limited airspeed that's sensed by the pitot-static system?

Gary

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There are a lot of operators flying turbine otters, year after year after year. Look a the pics in the links you posted. The smoked rivets are pretty much a dead giveaway as to what started that ball rolling. If this was some huge issue, outfits like AWA would have lost the otters years ago. I think poor maintenance and even poorer preflights are probably a much larger cause of problems than some prop blast over the tails.

BC12D-4-85 said:

^^^^What's normal cruise speed and how close is that to maximum? Edit: Like Vno or Vne?

Gary

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If memory serves, redline for turbine Otter landplane is 115 kts, seaplane 124 kts IAS. I've heard it is not easy to exceed those speeds in level flight by more than a few knots, especially if loaded.

If it lawn darted into the water and the tails aren't falling off these aircraft on a regular basis pilot incapacitation is the most likely cause.

I captured a screen shot of the tail end of that flight off FR24,
looks like it had been cruising at 700' doing 80 knots.
Pretty normal flight profile for these aircraft.
I saw two turbine otters (probably Kenmore's) flying the same path a day or two later.

I got a rare call for crane service on a Sunday, usually when that happens it's a overweight trucker stuck at the local Port of Entry until he gets lightened up. A rare chance to show my crane AND plane chops all at the same time. The Piper Saratoga landed gear up, pilot just forgot, I joshed him a bit until I remembered the times I've landed (Datum retracts) wheels down on snow, and skis down on the grass.

I rejected the first front rigging point, suggested by one of the helpers, of using the lift lug on the engine, the one that's there to pick the engine, not the whole front of the plane. Then I rejected another's idea of rigging to the motor mount, in front of the rubber mounts. I pointed out that using the mount structure that's bolted to the firewall, would not torque on the rubber donuts, and being "the crane guy", we did it my way..... The rear pick point, using a 4" wide strap to spread the load as much as possible, was directly under a fuselage station, didn't want to oil can that surprisingly thin tin. We took our time, made one adjustment on the rigging length, and then she levitated up at the normal AOA just high enough to let the pilot (finally) put the gear down. Based local, he then was able to tow it to his hangar. Fun job, beat swinging trusses. The funds earned are earmarked to go directly to "airplane stuff." Best of all, no local media coverage whatsoever.

courierguy said:

Best of all, no local media coverage whatsoever.

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Until now

You guys don't count. No N number visible, made sure of that.

Saratoga?

Web

wireweinie said:

Saratoga?

Web

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The rare high wing version. .

That’s ok. I can’t identify a thing on that crane.

That's what I was told, a Saratoga. I do know the fuselage skin was like tin foil, kinda surprised me what light gauge it seemed to be, gets the job done though.

Thinking back, after I hoisted it up high enough for him to put the gear down, and he motioned to me to let 'er down, I should have asked first, "you SURE the gear is down?"

No wing struts, looks like a 210