Oops, darn it...

[skywagon8a]

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.

“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.”

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!"?

[BC12D-4-85]

De Havilland DHC-3 OTTER radial engine Flight Manual> https://guidessimo.com/manual/downlo...anual-128.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

[mvivion]

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!"?

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

[mvivion]

De Havilland DHC-3 OTTER radial engine Flight Manual> https://www.manualslib.com/manual/12...c-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

Note the statement at the very bottom of page 64.

MTV

[mvivion]

De Havilland DHC-3 OTTER radial engine Flight Manual> https://www.manualslib.com/manual/12...c-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

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

[BC12D-4-85]

The original link didn't bother my Mac. Here's another> https://guidessimo.com/manual/downlo...anual-128.html

Gary

[mvivion]

The original link didn't bother my Mac. Here's another> https://guidessimo.com/manual/downlo...anual-128.html

Gary

Yes, my iPad opened it fine. PC didn’t like it.

MTV

[Paul Heinrich]

Is anyone besides me shocked and dismayed by the vast number of aircraft accidents listed? All pilots should qualify for hazard pay.

Here's the Preliminary Report for N3937M PA-12. See Page 2 for 08/11/2022 Arctic Village Alaska> https://data.ntsb.gov/carol-main-pub...th=8&year=2022

Gary

[ak49flyer]

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)

[BC12D-4-85]

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

[ak49flyer]

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...

[h2oavi8r]

NTSB Preliminary Report of DHC-3 Accident Released

https://data.ntsb.gov/carol-repgen/a...ort/105855/pdf

[stewartb]

Reno. Gold race for jets. Rest in peace.

https://youtu.be/zZzGdVQHoaQ

[StalledOut]

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.

[stewartb]

Cessna 180 accident at Whiskey Lake. The pilot, Janell Anderson was killed. I’m not the only one here who knew her or that brown-burnt orange 180 that was in the family for so many years. Say a prayer. Rest in peace, Janell.

[mvivion]

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

You may have answered your own question. Even a Beaver has limits in the wave action it can handle.

MTV

[Troy Hamon]

You may have answered your own question. Even a Beaver has limits in the wave action it can handle.

MTV

Have not heard any details but I had the impression it was a smaller un-named lake near Becharof where the accident occurred.

[Farmer Hank]

Heard today that the Carbon Cub raffled off in Alaska recently was damaged at Hot Springs, Montana. Prop strike and wing damage. My info is third hand, so someone else may know a lot more about this incident.

[stid2677]

I was told tonight that a float plane made a takeoff run on Chena Marina and aborted and turned around, the left float went under as he tried to make shore and sank nose down.

[BC12D-4-85]

A local Fairbanks C-185 fatality was reported today: 05-OCT-22 23:53:00Z N217C FAIRBANKS ALASKA CESSNA/185 ACCIDENT DESTROYED 1 AIRCRAFT CRASHED UNDER UNKNOWN CIRCUMSTANCES, FAIRBANKS, ALASKA. If the owner of record was aboard I knew him well since the 1960's.

Gary

Edit: This from another pilot:

Yes, jerry stansel, he drowned in the airplane. He had aborted a take off
and was taxing in and one float dug in and he went over. Someone at chena
marina has video of it. Bummer, guess the load pinned him in.

[h2oavi8r]

FAA Issues Emergency AD for DHC-3 Otter elevator auxiliary spar. Interesting to note that the FAA already published a notice of proposed rule making of a similar nature on February 8th and that’s based on a Transport Canada AD dated 1/19/2018. They’re still reviewing public comments.

https://www.aopa.org/news-and-media/...m_medium=email

https://drs.faa.gov/browse/excelExte...dalOpened=true

[ak49flyer]

That’s been a common area for cracks for a long time- please note nowhere have I seen any official link to any recent crashes related to these cracks, in spite of whatever online conjecture may be going on...

[BC12D-4-85]

I'd take lots of date/time stamped pics of those affected parts during the E-AD inspection. Might be valuable later.

Gary

[h2oavi8r]

That’s been a common area for cracks for a long time- please note nowhere have I seen any official link to any recent crashes related to these cracks, in spite of whatever online conjecture may be going on...

The AOPA article quotes the NTSB - “witness accounts are consistent with a flight control malfunction”. More NTSB quotes in the article.

The Emergency AD has a 3 day or 10 hour completion requirement.

[aktango58]

I believe the otter that crashed right after take off in Dry Bay early this summer was an elevator issue.

Not sure if it was the same failure, but hey- if a spar is failing it seems prudent to have it fixed. If it is a common issue, and some mechanics just blow it off 'until we have time' to fix it, as a pilot I would prefer an emergency AD.

Had enough of 'leave it for now' attitudes.

[Narwhal]

Heard today that the Carbon Cub raffled off in Alaska recently was damaged at Hot Springs, Montana. Prop strike and wing damage. My info is third hand, so someone else may know a lot more about this incident.

Looks true, and caused by a ground loop according to the FAA. Too bad, it was a beautiful airplane. I sure do enjoy flying my FX3, and it's awfully easy to land on 31's. I don't understand why this keeps happening. With that said, there but for the grace of god go I....

https://www.asias.faa.gov/apex/f?p=1...NAME:06-OCT-22

[ak49flyer]

I believe the otter that crashed right after take off in Dry Bay early this summer was an elevator issue.

Not sure if it was the same failure, but hey- if a spar is failing it seems prudent to have it fixed. If it is a common issue, and some mechanics just blow it off 'until we have time' to fix it, as a pilot I would prefer an emergency AD.

Had enough of 'leave it for now' attitudes.

Agree completely. I hate that the otter as a type is getting a bad rap from this; it’s an amazing airplane and I hope they keep flying for a long time. I do think, however that all personnel involve in the operation need to acknowledge the fact that these are 60+ year old airframes with 150+% hp that they were designed with, and treat them accordingly. This means actual inspections instead of pencil whipped 100hrs, and actual preflights and attention to details by pilots. Also actually spending money on maintenance. I’m not in any way condoning sloppy maintenance, but if that’s your approach, I’d suggest something a lot newer without 30k+ hrs of fatigue. Your sloppy maintenance may very well still kill you, but you might up the odds a little...

[ak49flyer]

I thought the Yakutat one was on approach to landing? I’ll have to look it up...

Edit: http://www.kathrynsreport.com/2022/0...rbine.html?m=1

Heard from another source it was severely aft loaded, but sounds like it could’ve been an elevator issue...?

[BC12D-4-85]

From the NPRM from 2/08/22: Edit> For the DHC-3 discussed

"Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would affect 38 airplanes of U.S. registry. The FAA also estimates that it would take about 145 work-hours per airplane to establish a corrosion prevention and control program and comply with the initial tasks of the program.

Based on these figures, the FAA estimates the cost of the proposed AD on U.S. operators to be $468,350 or $12,325 per airplane.

The FAA estimates it would take about 1work-hour to report any corrosion found during the proposed initial inspections, for an estimated cost of $85 per airplane.

The extent of damage found during the proposed initial inspections may vary significantly from airplane to airplane. The FAA has no way to determine the estimated cost of repair or replacement of damaged parts for each airplane or how many airplanes may need these repairs."

Gary

[skywagon8a]

.....with 150+% hp that they were designed with, and treat them accordingly. ...

Not only the increase in horsepower but also the change from a slow turning radial engine to a high rpm turbine. The vibrations generated by the two engines are vastly different which creates a totally different fatigue pattern with different types of failures. Over long periods of time new stuff happens which would not have happened had the engine not been changed.

[wireweinie]

Not only the increase in horsepower but also the change from a slow turning radial engine to a high rpm turbine. The vibrations generated by the two engines are vastly different which creates a totally different fatigue pattern with different types of failures. Over long periods of time new stuff happens which would not have happened had the engine not been changed.

This exact subject has been discussed a lot by mechanics and owners up here.

Web

[skywagon8a]

This exact subject has been discussed a lot by mechanics and owners up here.

Web

Did you get your PM?

[aktango58]

Not only the increase in horsepower but also the change from a slow turning radial engine to a high rpm turbine. The vibrations generated by the two engines are vastly different which creates a totally different fatigue pattern with different types of failures. Over long periods of time new stuff happens which would not have happened had the engine not been changed.

Defiantly an increase in fatigue with a turbine, they might actually stay in the air instead of landing somewhere remote due to the 1340 failing again and again

BUT, to be clear, my comment about poor inspections by some mechanics is not specific to an Otter, but an attitude.

[ak49flyer]

This exact subject has been discussed a lot by mechanics and owners up here.

Web

And just to add to the mix, the garret’s turn the opposite way; always wondered if/how that affected things on an airframe that was used to something else for the first 20k hrs. Have seen some crazy cracking on the stabilizer skins- had one with 3-4 cracks that showed up in 200-300 hours. Scab patched in the middle of the season, then the patches cracked almost right away. Reskinning with thicker material and fixing some cracked ribs put a stop to it. Also have seen some serious wing strut cracks, one had a strut that would vibrate so bad on takeoff, you couldn’t see the middle of it...

[skywagon8a]

And just to add to the mix, the garret’s turn the opposite way; always wondered if/how that affected things on an airframe that was used to something else for the first 20k hrs. Have seen some crazy cracking on the stabilizer skins- had one with 3-4 cracks that showed up in 200-300 hours. Scab patched in the middle of the season, then the patches cracked almost right away. Reskinning with thicker material and fixing some cracked ribs put a stop to it. Also have seen some serious wing strut cracks, one had a strut that would vibrate so bad on takeoff, you couldn’t see the middle of it...

You should witness a flutter analysis test when it is done in the hangar. The plane is placed on jacks and a vibration making device is attached. When different frequencies are introduced the airframe bends and twist like a bowl of jelly. I guarantee that if any of us ever saw the airplane wiggle like that in flight you would need more than a clean pair of shorts. These test are a safe way to determine what the safe dive speed may be without an inflight flutter test program. The test of a popular light twin I watched was done because they were getting different flutter speeds between different versions of the same airplane in flight. It was discovered that the presence of a large oxygen bottle fixed behind the baggage compartment was the culprit. Now who would have guessed that?

I'm not surprised the Otters are having issues after installing turbines.

Some SC.orgers here have this airplane, a PA-30.

[frequent_flyer]

You should witness a flutter analysis test when it is done in the hangar. The plane is placed on jacks and a vibration making device is attached.

Probably not the standard aicraft lifting jacks though as these would change the resonant frequencies seen in at least the wing structure. I saw the DC-9 Super 80 (later named the MD-80 series) in ground vibration test in the Douglas flight test hangar. That was many years ago but I think it was supported by a special bungee system attached to the landing gear.

This paper confirms my recollection - https://citeseerx.ist.psu.edu/viewdo...=rep1&type=pdf

[skywagon8a]

Probably not the standard aicraft lifting jacks though as these would change the resonant frequencies seen in at least the wing structure. I saw the DC-9 Super 80 (later named the MD-80 series) in ground vibration test in the Douglas flight test hangar. That was many years ago but I think it was supported by a special bungee system attached to the landing gear.

This paper confirms my recollection - https://citeseerx.ist.psu.edu/viewdo...=rep1&type=pdf

I don't recall what the support looked like, only that it was supported. It likely would have jumped off a standard lifting jack. My observation took place in 1966.

[Wingwrench]

We buzzed the Gee Bee Z many years ago, here is part 1 of the youtube vid.

https://www.youtube.com/watch?v=MtiN48ePYwA

[skywagon8a]

We buzzed the Gee Bee Z many years ago, here is part 1 of the youtube vid.

https://www.youtube.com/watch?v=MtiN48ePYwA

Notice how the stabilizer of the PA-30 is flexing at 20:. That was the issue which was being tested when I witnessed the analysis. Those stabilizers had a tendency to bend up or down at the mid span. This is what determined the Vd speed. Vne = 90% of Vd.

[TcraftF21]

I had 2 PA30s and the last one scared me with tail flutters. I use to descend from higher altitudes to approach altitude by putting descent rate at 300fpm until it reached the yellow arc and then it would start to flutter. Did it twice and nothing nothing seemed to fix it. It is now living in Australia.

Jim