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DHC Beaver down in Hawkesbury

Old 1st Jan 2018, 12:06
  #81 (permalink)  
 
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Originally Posted by Jerry Springer View Post
- Obviously if an a/c floats at a certain weight, then 100% of the weight is being supported.
- Yes floats are designed with a max buoyancy each.
- Yes the plane will sink if that is exceeded.
- Yes, the floats are designed to support 180% of your aircraft types MTOW.


FAR 23.751 requires that the 2 floats of a twin-float floatplane provide 180% fresh water buoyancy. To determine the maximum weight allowed for a seaplane equipped with two floats, divide the total displacement by 1.8.
Specific floats are designed for specific aircraft types. You could in theory put floats of reduced buoyancy capacity on your a/c, and reduce your MTOW accordingly - but that would be rather silly.
What you do, is select a set of floats with enough buoyancy so that the upper limit on your MTOW is not restricted by the buoyancy capacity of your floats.
So I as said, you will install floats that are designed to support 180% of your aircrafts MTOW.

I can’t really help you more on this. It’s really not that complicated, so I’ll leave it at that. Just google FAR 23.751 for more information on float requirements.
Was the aircraft on Wipline 6000 floats?
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Old 1st Jan 2018, 12:30
  #82 (permalink)  
 
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According to the Ch.7 video he crashed out of the scenic flight phase a few Km North of his departure point and was not taking off or landing. In the absence of a mechanical failure the next thing that ATSB should consider is the post stall instability of float aircraft and how pilots are trained to deal with it.
An inherent problem is the floats providing lift after the wings stall, or better still a float providing lift after a wing stalls. This does not seem to have been considered in the (usually) Canadian crash reports, with their emphasis being the lack of stall warning. Who's tried a power on 60 degree turning stall in a DHC-2 Beaver ? I have in a float M7 Maule, and although I kept the thing balanced the result was a nice flick roll entry (80 degrees) into an incip spin (at 6000'), which was a lesson not to be forgotten.
Sky9, that seems to describe stall characteristics for the landplane version ? There is more at para 1.10 in Transportation Safety Board of Canada - Aviation Investigation Report A09P0397 that expands on this. Also a turning accelerated stall in any case will have higher pitch/roll/yaw rates than with wings level at 1.0 Gz, in this case perhaps too much to recover from.
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Old 1st Jan 2018, 14:48
  #83 (permalink)  
 
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So much speculation...
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Old 1st Jan 2018, 16:03
  #84 (permalink)  
 
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Dont need to be "Low and Slow" to enter into a stall/spin incident.
Bearing in mind the number of people on board plus, maybe, luggage.
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Old 1st Jan 2018, 17:45
  #85 (permalink)  
Below the Glidepath - not correcting
 
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Gareth was highly experienced with many thousands of hours on floats too - which if anything makes it even more unusual.
Sadly, any casual examination of accident reports will show time after time that accident rates and experience levels are not related. The most experienced pilots end up crashing in manners similar to the most inexperienced. The only difference is the level of surprise when our most experienced colleagues end up as an accident statistic.

As for the the "never mind the safety briefing, just head for the suckers gap.." approach to aviation mentioned in a previous post; again, just look at the accident reports from the 60's and 70's to see how that turned out for a lot of people. The hundreds of deaths each year from basically sheer stupidity and ignorance are thankfully a long way behind us. Hopefully only a few people are advocating a return to those days.
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Old 1st Jan 2018, 18:36
  #86 (permalink)  

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From the Transport Canada report identified by The Wala Zone:


In 1947, the Beaver was certified to British Civil Airworthiness Requirements and its stall characteristics were found to be acceptable. However, the Beaver demonstrates little or no pre-stall buffet and, if a warning system is not installed, the onset of the stall may surprise pilots.

Test flights conducted in 1992 showed that the float-equipped Beaver (aft CG limit, wings level and at maximum continuous power) stalled at 55 mph indicated airspeed (IAS) with flaps in the takeoff setting and at 54 mph IAS with flaps in the landing setting.

Turn stall tests were not performed with a float-equipped Beaver. When a wheel-equipped aircraft was stalled at a 30º bank angle, it pitched nose down and rolled both into and out of the turn. The maximum roll was 50º. The maximum altitude loss was 100 feet before a pilot, using the proper technique, regained controlled flight. The test pilot noted that the Beaver displayed little or no pre-stall warning buffet.

Certification flight tests are conducted under controlled conditions. Under less than ideal conditions, like wind turbulence and unintended sideslip, stall characteristics could be aggravated with larger roll angles and increased altitude loss. Additionally, when an aircraft is unintentionally stalled, a pilot may not immediately recognize the condition and altitude losses in excess of 100 feet could be expected.

Some of the effects of an aft CG include:

decreased stall speed of an aircraft;
decreased longitudinal stability;
violent stall characteristics; and
poor stall recovery. 12
A 2009 FAA memorandum described the stall characteristics of the Beaver with a forward CG as being docile and predictable. However, many approved modifications have been applied to increase payload and make it easier to load to the aft CG limits. The FAA suggests the Beaver's stall characteristics in an aft CG condition are unstable and unpredictable, and that flight excursions with an aft CG are often unrecoverable at low altitude.
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Old 1st Jan 2018, 20:02
  #87 (permalink)  
 
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Originally Posted by funfly View Post
Bearing in mind the number of people on board plus, maybe, luggage.
It was a dinner cruise - they wouldn't have had luggage.

DF.
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Old 1st Jan 2018, 20:28
  #88 (permalink)  
 
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From a retired highly experienced Beaver pilot who flew the accident aircraft in a different guise (no floats). "Put on flap and the Beaver will out turn any aircraft I have flown, try a steep turn flapless and it will fall out of the sky"
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Old 1st Jan 2018, 20:55
  #89 (permalink)  
 
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Just a point about the video from the jet skier showing the plane seemingly at 'scenic flight' altitude.

I haven't seen this verified anywhere as being footage of the actual flight. I spend a lot of time in that area and the SSP Beavers fly over several times a day, so even though this footage *may* have been of the flight, it may also not have been.
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Old 1st Jan 2018, 22:52
  #90 (permalink)  
 
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Sadly, any casual examination of accident reports will show time after time that accident rates and experience levels are not related. The most experienced pilots end up crashing in manners similar to the most inexperienced. The only difference is the level of surprise when our most experienced colleagues end up as an accident statistic.

As for the the "never mind the safety briefing, just head for the suckers gap.." approach to aviation mentioned in a previous post; again, just look at the accident reports from the 60's and 70's to see how that turned out for a lot of people. The hundreds of deaths each year from basically sheer stupidity and ignorance are thankfully a long way behind us. Hopefully only a few people are advocating a return to those days.
FER-ZACKERLY - those words and those views warrant an acceptance (and not just at face value) by as many interested in this pertinent subject - as can be mustered.

(Quibble here - wrong use of "hopefully')
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Old 2nd Jan 2018, 00:05
  #91 (permalink)  
 
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I suspect there is quite a bit of "reading into" going on here in relation to the original comments made about pre-takeoff briefings. I have to admit to disliking the verbiage which seems to accompany so many people's aviating these days, there is a big difference between having a clear mental plan and picture of the surroundings, and spouting a some formulaic nonsense that is so beloved of a certain type of instructor.

I flew with one muppet who delivered a beautiful briefing before every takeoff, right down to "I'll land straight ahead or not more than 30 degrees either side of the centreline..." and promptly overshot the field when he suffered an EFATO (in an LSA type), instead of turning approximately 70 degrees (from 400' odd) and landing on a cross runway. So yes, aviation is a dynamic environment.
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Old 2nd Jan 2018, 00:47
  #92 (permalink)  
 
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pic of craft

ac as I snapped it 29/12/17

HRRZI C(AC) <- 0,,E: Seaplane VH-N00

Last edited by morbos; 2nd Jan 2018 at 02:36. Reason: Wrong date
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Old 2nd Jan 2018, 00:48
  #93 (permalink)  
 
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Spinex I take issue with the term "Muppet" here. I was taught exactly the same briefing and actions as said muppet.

I have not been trained to do a power off 70 degree turn at 400'. No one has demonstrated one to me and I certainly ain't going to try it without serious testing. So take your smug comment and stick it.
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Old 2nd Jan 2018, 01:06
  #94 (permalink)  
 
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So take your smug comment and stick it.
Sunfish. I thought your comment to Spinex was a bit over the top and unnecessary. That sort of reply discourages future contributors from having their say. All he said was that some pilots give superfluous pre-take off safety briefings. I agree.
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Old 2nd Jan 2018, 01:18
  #95 (permalink)  
 
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. flew with one muppet who delivered a beautiful briefing before every takeoff, right down to "I'll land straight ahead or not more than 30 degrees either side of the centreline..." and promptly overshot the field when he suffered an EFATO (in an LSA type), instead of turning approximately 70 degrees (from 400' odd) and landing on a cross runway. So yes, aviation is a dynamic environment.
There is no way you should be doing large turns with an engine out at 400'. I'd take the controlled crash at low speed wings level, than try and be a hero and run the risk of stalling the aircraft at 200'. Do you have any idea what speed you would stall at in a 45 degree bank turn? Turnbacks are to be considered but only above a certain altitude.

I suspect this accident report will have a bit of a speel on lift vectors and angles of bank and their relationship.
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Old 2nd Jan 2018, 01:49
  #96 (permalink)  
 
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A very tragic day for all six and sadly..it appears once again that a dynamic "failure" appears paramount in all of this. No end of CASA fixes will prevent a repeat…( The Grumman in Perth)..the generic.."failure" is the tapestry of what we do in aviation and its pure training and attention to the failure dynamic that keeps us aware..ANY hesitation to attend to this will cause a very high risk of incident… RIP and a sad day for all who fly..
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Old 2nd Jan 2018, 04:03
  #97 (permalink)  
 
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Originally Posted by Sunfish View Post

I have not been trained to do a power off 70 degree turn at 400'. No one has demonstrated one to me and I certainly ain't going to try it without serious testing. So take your smug comment and stick it.
I'd sure as hell never pax with you Sunfish!

Are you saying you would not turn more than 30 degrees to right or left in an EFATO scenario? Scary. Where do you draw the line? 70 degrees is nothing from 400ft and sure as hell nowhere near 180.
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Old 2nd Jan 2018, 04:14
  #98 (permalink)  
 
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Model of seaplane that killed five Britons in Sydney's north 'reliable': Investigator

Model of seaplane that killed five Britons in Sydney's north 'reliable': investigator

By Patrick Begley

The model of seaplane that crashed and killed six people on New Year's Eve is generally reliable, according to a transport safety official leading the investigation.

But investigators do not know if the plane had the stall warning system recommended by Canadian authorities after the same model crashed and killed another British family in 2015.

The Sydney Seaplanes aircraft plunged into Jerusalem Bay north of Sydney, killing British chief executive Richard Cousins, 58, his sons Edward, 23, and William, 25, his fiancée Emma Bowden, 48, her daughter Heather, 11, and pilot Gareth Morgan, 44.

The plane remains largely intact beneath 13 metres of water.

"The aircraft took off in a north-easterly direction, followed by a turn to the north-east, then a subsequent right hand turn prior to impact," Nat Nagy, an executive director of the Australian Transport Safety Bureau, said.

The 1964 aircraft then sank and settled on the bottom of the river in an "inverted, slightly nosedown altitude", Mr Nagy continued. He could not confirm that the plane nose-dived before hitting the water.

Authorities hoped to have recovered the plane by the end of the week. They may attempt to float it to the surface with internal airbags, pull it up with a crane, or both.

Three investigators from the ATSB are working to piece together the plane's brief, final flight, looking at factors from pilot history to maintenance to components.

In 2015, a plane of the same kind, a DHC-2 Beaver, crashed in Quebec, Canada, killing six on board. The Canadian Transport Safety Bureau recommended in September that all such planes be fitted with mandatory stall warning systems.

Mr Nagy said he did not know if the Sydney Seaplanes aircraft had this system but "we haven't seen any systemic issues with this aircraft".

Asked whether the model was reliable, he said "an aircraft that's been used this long in this many operations, I would say yes".

The safety bureau is appealing for witnesses to come forward, especially those who have video footage of the flight.

Investigators will try to recover any footage taken on the flight from mobile phones or body-cameras, before finishing a preliminary report within a month.
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Old 2nd Jan 2018, 05:42
  #99 (permalink)  
 
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Originally Posted by Sunfish View Post
I have not been trained to do a power off 70 degree turn at 400'. No one has demonstrated one to me and I certainly ain't going to try it without serious testing.
i strongly recommend you get some training in this, or complete an advanced Aircraft control course.

i know for a fact, that i can turn my aircraft, 180 deg, at 70 deg AOB, and return to the field from an EFATO from 600 ft. i have been taught with an aerobatic instructor, and practiced the manoeuvre many time at altitude to test this exact limit.

so, now as part of my take of brief, which is altered to reflect the airfield im flying from and known terrain ahead, when passing 600 ft, the turnback now becomes an option.

As for the tragedy on New Years eve, it appears the stall spin scenario is a leading contender

faceblah blah channel ten news ATSB video . /tennews/videos/1771343589602607/
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Old 2nd Jan 2018, 07:08
  #100 (permalink)  
 
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Betcha can't do that in a MTOW departure in a PA-32 for example and live to tell us all how good you are/were.
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