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Oops, darn it...

MoJo said:
I read the ntsb report on this crash, and the trim was full nose up. ???

In every picture I find of this airplane, including at a different accident, the stab is set full nose up.

Why is that?
Click to expand...

That's a good question ( NTSB ANC22FA066). I spoke with a local FSDO inspector that first mentioned the trim position. Driving around the local airports I saw several PA-12's on conventional gear with PA-18 empennage and long engine mounts (and most with upgraded engines/props). They had their trim-horizontal stabilizer nose resting near or full down. Most PA-18's not as much. This accident plane also had large tires and a Crosswinds STOL kit but I have no idea about that relationship to the trim.

Maybe PA-12 owners could comment on their typical trim position inflight or after landing?

Gary
 
I don't know the plane or the pilot. Unless I have a pretty heavy load I usually do all my landings with full nose up trim in case I need to really get on the brakes. Takeoff is 9 turns nose down , unless I re trim for takeoff as I taxi back to the hanger mine will be at or close to full nose up when parked. A long mount 12 with a big motor and Borer will likely use more nose up trim, could be just how that plane is set up. Some pilots just don't use the trim much and just strong arm the entire flight. It is really just wild ass guesses unless you knew the pilot and plane.
DENNY
 
Two pics of the accident aircraft prior show the trim to be at or near full nose up when at rest. The only reason it was discussed locally after the accident is that we, as current non-owners of that model, wondered why that position? That's all and it's not being guessed by me whether or not it contributed to the crash. I owned a PA-12-180 for a few years ('97-2001) on wheels, skis, and floats but don't recall the typical trim position in flight or after landing. And, we knew the pilot and plane for years.

Gary
 
The report says he was at gross. If he was fighting "violent" winds he was likely flying at or below Va, and when heavy having the trim set for nose up makes sense. As it does for lots of planes post-landing when the pilot doesn't reset it for the next flight. Personally I trim as part of my pre-takeoff routine, not post-landing, so my trim in parking is typically near the nose up limit.
 
Now fill the plane with passengers and fuel then repeat the slow flight-stall series from about 04:00 on. In gusty conditions preferably. I don't know - maybe there's a safety margin in there somewhere.

Gary
 
BC12D-4-85 said:
Now fill the plane with passengers and fuel then repeat the slow flight-stall series from about 04:00 on. In gusty conditions preferably. I don't know - maybe there's a safety margin in there somewhere.

Gary
Click to expand...
Notice at 5:20 he says at full gross weight the stall speed is over 100. I didn't hear him mention cruise speed, but at full gross there doesn't appear to be much margin
 
^^^^Yes. and ~torque will roll you inverted, and ~ full power on the tail stalls and it snaps over straight down (my words - watch for actual text). I bet that pilot is very good at what he's does, but some may not be as well qualified.

Then there's this legalize word salad regarding an Otter crash in Alaska. Note the STOL kit data and rear CG limits tested. https://www.casemine.com/judgement/us/5ea528064653d00e93023f2f

Gary
 
stewartb said:
The report says he was at gross. If he was fighting "violent" winds he was likely flying at or below Va, and when heavy having the trim set for nose up makes sense. As it does for lots of planes post-landing when the pilot doesn't reset it for the next flight. Personally I trim as part of my pre-takeoff routine, not post-landing, so my trim in parking is typically near the nose up limit.
Click to expand...

in my 12's, with long mounts, the more weight I add the more the trim moves to nose down for cruise and landing, as all added weight goes to a rearward CG. Empty I land with full nose up trim, at gross I am probably several turns towards nose down on landing. With a gross weight increase and my ELT way back by the tail at full gross my trim is WAY nose down in flight.
 
MT12 said:
in my 12's, with long mounts, the more weight I add the more the trim moves to nose down for cruise and landing, as all added weight goes to a rearward CG. Empty I land with full nose up trim, at gross I am probably several turns towards nose down on landing. With a gross weight increase and my ELT way back by the tail at full gross my trim is WAY nose down in flight.
Click to expand...

In my PA-12 with 180hp & short mount, my trim is always somewhere in the middle. After I take off, I set the trim for cruise & never have to adjust it again for that flight. When slowing down for landing, I add a notches of flaps to counteract the pitch down. No horsing around needed. The controls are light enough to fly with two fingers.
The only time the trim goes to full nose up or full nose down is at the annual.
 
skywagon8a said:
Notice at 5:20 he says at full gross weight the stall speed is over 100. I didn't hear him mention cruise speed, but at full gross there doesn't appear to be much margin
Click to expand...

I noticed that as well. That’s quite different than what appears in the print version, which makes MUCH more sense.

There, he states that after takeoff, flaps up and 90 knots for climb. He then quotes the pilot: “The biggest gotcha is that the Otter can stall at nearly cruise speed with a heavy load when the flaps are up and the pilot pulls hard during a steep turn.” He went on: “Then, the torque can roll the airplane inverted.” The article continues: “Steep turns with partial flaps, however, are extremely forgiving and the Otter can turn around using minimal real estate.”

That is classic deHavilland flight characteristic. When I checked out in the Beaver, Jack Cory really beat me up with turns…..slow down in anticipation, lower some flap, then turn. At altitude, attempting steep turns with no flap resulted in pretty impressive stalls. And flaps in these planes require some monkey motion: Select flaps to down, then pump them down to the desired position. Not something you’re going to do once you’re started in a turn.

The Baron STOL kit was specifically address this characteristic. I’ve never flown a Baron wing Beaver, but a stock plane will turn with the best….IF you have flaps deployed.

Equipped with a Baron STOL kit, I can’t believe that plane stalls at 100 knots in level flight.

MTV
 
I've never had the opportunity to fly an Otter. But this part gives me reservations about letting an inexperienced pilot (I don't just mean low in hours. What type of flying was it?) loose in one.
mvivion said:
“The biggest gotcha is that the Otter can stall at nearly cruise speed with a heavy load when the flaps are up and the pilot pulls hard during a steep turn.” He went on: “Then, the torque can roll the airplane inverted.”
Click to expand...
Perhaps this could be the cause of some of the other accidents which happened when sightseeing flights ventured into marginal weather in passes? "Oops, I'd better get this beast turned around quickly!"?
 
Last edited:
skywagon8a said:
I've never had the opportunity to fly an Otter. But this part gives me reservations about letting an inexperienced pilot (I don't just mean low in hours. What type of flying was it?) loose in one.
Perhaps this could be the cause of some of the other accidents which happened when sightseeing flights ventured into marginal weather in passes? "Oops, I'd better get this beast turned around quickly!"?
Click to expand...

That almost certainly was the cause of severa Beaver accidents in passes, which is why Corey had me turning (with flaps deployed) till I was blue in the face. Corey worked deHavilland aircraft for some operators, so knew the breed well. It’s amazing how well a Beaver turns with flaps out, and how ugly they get in a steep turn without flaps.

Never flown an Otter, but Corey said they were the same.

But, that accident Otter had the Baron kit installed.

MTV
 
BC12D-4-85 said:
De Havilland DHC-3 OTTER radial engine Flight Manual> https://www.manualslib.com/manual/1297670/De-Havilland-Dhc-3-Otter.html

It's an interesting read. The local University had one parked at their Auroral rocket test site north of town. They tried to give it away to my employer in the later 1980's. I said if you can move the tail without power then ok. It disappeared and now is quite valuable if intact.

Gary
Click to expand...

Note the statement at the very bottom of page 64.

MTV
 
BC12D-4-85 said:
De Havilland DHC-3 OTTER radial engine Flight Manual> https://www.manualslib.com/manual/1297670/De-Havilland-Dhc-3-Otter.html

It's an interesting read. The local University had one parked at their Auroral rocket test site north of town. They tried to give it away to my employer in the later 1980's. I said if you can move the tail without power then ok. It disappeared and now is quite valuable if intact.

Gary
Click to expand...

And, By the way, opening that web link installed a malware on my PC. I was able to get rid of it by un installing and re-installing the browser software. I don't recommend opening that link.

MTV
 
I dunno- try listing all the auto incidents; the vast majority of the ntsb listings are the equivalent of a “fender-bender”. I for one don’t think pilots deserve to be any more overpaid... (flame suit on)
 
Maybe we are experiencing the consequences of a lack of flying regularly? Not sure about that but up here for the last few years many owners and aircraft have been ground bound more than usual (I'm one). Costs of fuel (~$8.00), maintenance (~$180/hr for some), parts cost, and even more so a lack of availability, has created selective flying. Instead of just going for a fun ride many are focusing on special events and seasonal trips. I don't have hard stats on flight hours over time and season, but I bet it's not increasing for Part 91 ops. So planes and pilots corrode together which ups the risk factor and may affect the potential for incidents or accidents.

Use it or loose it. I just finished an Annual and now to get current.

Gary
 
The Otter stall speeds mentioned above sounded crazy to me, and I just ran across a chart in the Texas Turbine(Garrett) FMS. I’ll try to post a screenshot...
 

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On 09/19/2022 Alaska Wildlife Troopers in Kodiak received a report from an In Reach device of a plane crash at Becharof Lake near King Salmon. A DHC-2 Beaver bush plane crashed while attempting to take off from the lake. The three occupants aboard the aircraft suffered minor injuries from the aircraft collision. All parties were rescued by another bush plane and were examined in Naknek for their minor injuries.




37 mile long lake....wind right down the lake too. Wonder what happened here. Glad no one was seriously hurt.
 
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