---------------------------------------------------------- Commander-List Digest Archive --- Total Messages Posted Mon 04/28/08: 5 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:05 AM - Re: Survey Commanders (Bill Hamilton) 2. 04:11 AM - Re: Survey Commanders (Barry Collman) 3. 06:01 AM - Re: Survey Commanders (nico css) 4. 06:51 AM - Re: Survey Commanders (Richard & Jacqui Thompson) 5. 03:02 PM - Re: Survey Commanders (Craig Kennedy) ________________________________ Message 1 _____________________________________ Time: 04:05:51 AM PST US From: "Bill Hamilton" Subject: RE: Commander-List: Survey Commanders Folks, To add a little to what Richard has said, and as a result of having been a long standing member of the CASA Standards Consultative Committee. Post WWII, a lot of work was done on fatigue in Australia, as the actual life of an individual airframe varies enormously, depending on the accumulation of fatigue damage, physical damage and corrosion damage. This included a rig test to destruction of 100 sets of new P-51D wing sets (left over after Korea), and this resulted in the "bell" curve used, to this day, for likely fatigue life distribution in aluminium structures. A desire to "lead the world" can be very expensive, if not very carefully managed, and to say that some "over-reacted" is an understatement, at great expense to many of us. However, the professional engineers of the day were not entirely unjustified. Australia's "good weather" produces a lot of heat turbulence, often well beyond design assumptions, as fitting a wide variety of GA, commuter and military aircraft with recording "fatigue meters" has shown. For a while, (and just for my own interest) I had a recording G meter mid-ships under floor in AT-28D, 51-3588. It was instructive to compare the tell-tale needle on the instrument panel G meter, and the recorder. The panel meter always under-recorded peak G, and of course gave no measure of duration. A number of in-flight break-ups of airline aircraft, including 3 Vickers Viscounts, spurred the efforts. To add to the mix, until 1998, Australia had its own design and certification rules, which, in the case of Aero-Commander, resulted in the certification of aircraft at higher gross weights than the factory/FAA, the higher weight certification included a spar strap. When the (now) well known problems of the cold bent spar extrusions surfaced, the AD spar straps were based on the existing Australian certification. One of the reasons then Department of Civil Aviation, DCA, took such a detailed interest, was the fact that they had a fleet of Aero-Commander, various models over the years. Richard's aircraft was delivered new to DCA. The last models their successors used was the Commander 1000 (695A), one has just changed hands in US. The problems of the cold bent extrusions at the wing/body point is well understood, the management by AD has been effective. The problem of dissimilar metal corrosion in spar caps is (now) well understood, but is/was a serious issue. The problems of off spec . material has no answer, it must be replaced. As all our aircraft get older, the results of corrosion becomes increasingly important, if you have never found any, you haven't looked hard enough - with the possible exception of Richard's aircraft, all the DCA/DOA aircraft were ordered with US MilSpec corrosion protection, with all airframe components chromate primed or anodised before assembly, with all drilled fastener holes treated to a brush of primer before "wet" riveting. As FAA produce "ageing aircraft" programs (Cessna SIDs) you will find a remarkable similarity between the inspection hours nominated, and the long standing Australian fatigue life/spar replacement ADs for C402 etc. Indeed, some of the new FAA/Cessna figures are marginally less than the Au AD. As we have pulled apart a few 402 for the SIDs, we have found some scary stuff. There are some very high hour airframes in Australia, when Cessna published the retirement life for the Conquest of 22,000 hours, I doubt they thought it would have had much effect. In Australia, 9 aircraft were grounded. If you have a look at the evolution of FAR 23 structural design standards, you will see the increasing attention to fatigue life, from memory, the Piper Tomahawk was the first aircraft certified after the first FAR 23 amendment to include fatigue justification, hence the wing life. Take the AC structural ADs very seriously, none are unjustified. Having said that, look at the Australian AD Richard put up, the life limits are two or three times the equivalent for most Cessna /Piper, that's telling us something. Neither of the two in-flight breakups of AC-500U or S appears to be fatigue related, being symmetrical downward bending failures just outboard of the engine nacelles. CASA (compared to FAA) is a problem, there have been some good changes in the senior management in the last two years, including several very competent people from the "Eastern Pacific Rim", but it takes a long time to turn the ship of state around. Cheers, Bill Hamilton From: owner-commander-list-server@matronics.com [mailto:owner-commander-list-server@matronics.com] On Behalf Of Richard & Jacqui Thompson Sent: Monday, April 28, 2008 4:37 PM Subject: RE: Commander-List: Survey Commanders Before you go Gulp. Understand that CASA makes your FAA look totally professional. This paper was written by an academic and as history has proved we have very strong airplanes. Take note that the wing is essentially a fail safe design. If it was not then a whole lot more airplanes would have crashed. One classic example in the report is the case of ZK-BWA and the pictures. What was not explained was that this aircraft had been badly damaged previously and not repaired correctly. The other problem is that a lot of the corrosion found in Aussie aircraft was due to the fact that they had been used in low level coastal work and really had not been looked after. This paper also ends in about 1995. I believe that in the 1999 the FAA had Twin Commander almost re certify their wings at great expense, destroying numerous airframes. Strangely enough they passed with flying colours. (which must have pissed the FAA off no end). Even our wonderful CASA went on to their 8th amendment of their AD on spar life http://www.casa.gov.au/airworth/airwd/ADfiles/under/ac/AC-066.pdf . I believe that a lot of accidents and especially in flight break ups have had a lot to do with the airframe being stressed way beyond its limits, usually in foul weather. You just have to do little thinking looking at the size of the things tale and then imagine the loads it has to take especially if you don't go with the flow and try to manhandle it in turbulence. You can break anything if you try hard enough. Cheers Richard -----Original Message----- From: owner-commander-list-server@matronics.com [mailto:owner-commander-list-server@matronics.com] On Behalf Of nico css Sent: Monday, 28 April 2008 10:57 AM Subject: RE: Commander-List: Survey Commanders _____ From: owner-commander-list-server@matronics.com [mailto:owner-commander-list-server@matronics.com] On Behalf Of mike floyd Sent: Friday, April 25, 2008 2:10 PM Subject: RE: Commander-List: Survey Commanders Read this: http://www.casa.gov.au/airworth/papers/aerocommander.pdf _____ From: WINGFLYER1@aol.com Subject: Re: Commander-List: Survey Commanders I have a 680. What caused the spars to break? _____ Need a new ride? Check out the largest site for U.S. used car listings at AOL Autos . " target=_blank>http://www.matronics.com/Navigator?Commander-List p://forums.matronics.com blank>http://www.matronics.com/contribution _____ Express yourself wherever you are. Mobilize! href="http://www.matronics.com/Navigator?Commander-List">http://www.matronic s.com/Navigator?Commander-List href="http://forums.matronics.com">http://forums.matronics.com href="http://www.matronics.com/contribution">http://www.matronics.com/c http://forums.matronics.com http://www.matronics.com/contribution ________________________________ Message 2 _____________________________________ Time: 04:11:47 AM PST US From: "Barry Collman" Subject: Re: Commander-List: Survey Commanders Hello All, Regarding ZK-BWA, I have a copy of the official Report into the accident. Richard is, of course, correct in saying that "this aircraft had been badly damaged previously". While being flown in the USA prior to delivery, it was subjected to "an extremely heavy landing which necessitated structural repairs before the aircraft could again be flown". It was also evident that "structural defects had existed in the rear spar caps of the starboard wing prior to the accident". It was evidently the practice of the pilot to fly very low over Mount Ruapehu to give his passengers a good look at a crater lake. There is evidence to suggest that there was strong turbulence in that area on the day of the accident. There is a strong possibility that, due to turbulence, the propeller on the starboard side had struck an isolated projection somewhere on the top of the mountain. Severe engine vibration resulted from the now unbalanced propeller blades and shortly afterwards, it encountered the severe turbulence. The starboard wing, which had already been weakened by three defective spar caps, was subjected to stresses and loadings beyond its capacity to withstand. There were instances known in the aircraft's history of damage to the starboard wing. One was when the starboard prop struck a metal stand while taxying with the engine running at high rpm. The tips of all three blades were damaged and the aircraft was flown in that condition. Takeoff and landing was effected on both engines, but it is not known if the right prop was feathered during the flight, to eliminate engine vibration. The prop damage was within repairable limits. On another occasion, the main gear was "forcibly extended when the aircraft encountered sudden turbulence." Evidently, "under exceptional positive gust loadings in the region of 6g the gear will be forcibly ejected from the retract wells." I am currently looking at Commander accidents where airframe disintegration occurred, but am only a relatively small way into the exercise. However, so far expressions like "exceed design stress limits" seem to appear on a very regular basis. These are coupled with expressions like "spatial disorientation", "severe turbulence" and "airframe icing". So, Commanders do not fall out of the sky for no apparent reason, as of course, we all know. Best Regards, Barry ----- Original Message ----- From: Richard & Jacqui Thompson To: commander-list@matronics.com Sent: Monday, April 28, 2008 7:36 AM Subject: RE: Commander-List: Survey Commanders Before you go Gulp. Understand that CASA makes your FAA look totally professional. This paper was written by an academic and as history has proved we have very strong airplanes. Take note that the wing is essentially a fail safe design. If it was not then a whole lot more airplanes would have crashed. One classic example in the report is the case of ZK-BWA and the pictures. What was not explained was that this aircraft had been badly damaged previously and not repaired correctly. The other problem is that a lot of the corrosion found in Aussie aircraft was due to the fact that they had been used in low level coastal work and really had not been looked after. This paper also ends in about 1995. I believe that in the 1999 the FAA had Twin Commander almost re certify their wings at great expense, destroying numerous airframes. Strangely enough they passed with flying colours. (which must have pissed the FAA off no end). Even our wonderful CASA went on to their 8th amendment of their AD on spar life http://www.casa.gov.au/airworth/airwd/ADfiles/under/ac/AC-066.pdf . I believe that a lot of accidents and especially in flight break ups have had a lot to do with the airframe being stressed way beyond its limits, usually in foul weather. You just have to do little thinking looking at the size of the things tale and then imagine the loads it has to take especially if you don't go with the flow and try to manhandle it in turbulence. You can break anything if you try hard enough. Cheers Richard -----Original Message----- From: owner-commander-list-server@matronics.com [mailto:owner-commander-list-server@matronics.com] On Behalf Of nico css Sent: Monday, 28 April 2008 10:57 AM To: commander-list@matronics.com Subject: RE: Commander-List: Survey Commanders ------------------------------------------------------------------------- ----- From: owner-commander-list-server@matronics.com [mailto:owner-commander-list-server@matronics.com] On Behalf Of mike floyd Sent: Friday, April 25, 2008 2:10 PM To: commander-list@matronics.com Subject: RE: Commander-List: Survey Commanders Read this: http://www.casa.gov.au/airworth/papers/aerocommander.pdf ------------------------------------------------------------------------- ----- From: WINGFLYER1@aol.com Date: Fri, 25 Apr 2008 16:49:25 -0400 Subject: Re: Commander-List: Survey Commanders To: commander-list@matronics.com I have a 680. What caused the spars to break? ------------------------------------------------------------------------- ----- Need a new ride? Check out the largest site for U.S. used car listings at AOL Autos. " target=_blank>http://www.matronics.com/Navigator?Commander-Listp://foru ms.matronics.comblank>http://www.matronics.com/contribution ------------------------------------------------------------------------- ----- Express yourself wherever you are. Mobilize! href="http://www.matronics.com/Navigator?Commander-List">http://www.mat ronics.com/Navigator?Commander-Listhref="http://forums.matronics.com">h ttp://forums.matronics.comhref="http://www.matronics.com/contribution"> http://www.matronics.com/c http://forums.matronics.comhttp://www.matronics.com/contribution ________________________________ Message 3 _____________________________________ Time: 06:01:38 AM PST US From: "nico css" Subject: RE: Commander-List: Survey Commanders That's true, Richard. And some balance in the perspective. Even the tail of an airliner came off a couple of years ago due to excessive rudder input, didn't it? And the fire-fighting planes also lost a few due to overstressing or fatigue or both. What I couldn't figure out is why the spar is bent forward. The simplicity of having a straight spar should have outweighed the benefits that it might have had (and I am not saying there weren't any, I am just ignorant) being bent. Ted Smith had to know that it would induce torque on the spar. Nico _____ From: owner-commander-list-server@matronics.com [mailto:owner-commander-list-server@matronics.com] On Behalf Of Richard & Jacqui Thompson Sent: Sunday, April 27, 2008 11:37 PM Subject: RE: Commander-List: Survey Commanders Before you go Gulp. Understand that CASA makes your FAA look totally professional. This paper was written by an academic and as history has proved we have very strong airplanes. Take note that the wing is essentially a fail safe design. If it was not then a whole lot more airplanes would have crashed. One classic example in the report is the case of ZK-BWA and the pictures. What was not explained was that this aircraft had been badly damaged previously and not repaired correctly. The other problem is that a lot of the corrosion found in Aussie aircraft was due to the fact that they had been used in low level coastal work and really had not been looked after. This paper also ends in about 1995. I believe that in the 1999 the FAA had Twin Commander almost re certify their wings at great expense, destroying numerous airframes. Strangely enough they passed with flying colours. (which must have pissed the FAA off no end). Even our wonderful CASA went on to their 8th amendment of their AD on spar life http://www.casa.gov.au/airworth/airwd/ADfiles/under/ac/AC-066.pdf . I believe that a lot of accidents and especially in flight break ups have had a lot to do with the airframe being stressed way beyond its limits, usually in foul weather. You just have to do little thinking looking at the size of the things tale and then imagine the loads it has to take especially if you don't go with the flow and try to manhandle it in turbulence. You can break anything if you try hard enough. Cheers Richard -----Original Message----- From: owner-commander-list-server@matronics.com [mailto:owner-commander-list-server@matronics.com] On Behalf Of nico css Sent: Monday, 28 April 2008 10:57 AM Subject: RE: Commander-List: Survey Commanders _____ From: owner-commander-list-server@matronics.com [mailto:owner-commander-list-server@matronics.com] On Behalf Of mike floyd Sent: Friday, April 25, 2008 2:10 PM Subject: RE: Commander-List: Survey Commanders Read this: http://www.casa.gov.au/airworth/papers/aerocommander.pdf _____ From: WINGFLYER1@aol.com Subject: Re: Commander-List: Survey Commanders I have a 680. What caused the spars to break? _____ Need a new ride? Check out the largest site for U.S. used car listings at AOL Autos. " target=_blank>http://www.matronics.com/Navigator?Commander-List p://forums.matronics.com blank>http://www.matronics.com/contribution _____ Express yourself wherever you are. Mobilize! href="http://www.matronics.com/Navigator?Commander-List">http://www.matronic s.com/Navigator?Commander-List href="http://forums.matronics.com">http://forums.matronics.com href="http://www.matronics.com/contribution">http://www.matronics.com/c http://forums.matronics.com http://www.matronics.com/contribution ________________________________ Message 4 _____________________________________ Time: 06:51:31 AM PST US From: "Richard & Jacqui Thompson" Subject: RE: Commander-List: Survey Commanders Thanks for that Bill, Have not seen you for a while. My 680E has the primed interior and has very little corrosion. The only place is on the engine trusses and that has been ground out under the watchfull eye of my friendly Car35 guy. He reckons the amount taken out will not make a rats arse difference to the overall strength of the truss. The end is in sight, the old girl should be in the paperwork stages in a couple of months. I am building a new hangar down at Wedderburn to house her. The one I have there is not quite big enough, about a foot shy on span and about 3 foot shy on tail. Cheers Richard -----Original Message----- From: owner-commander-list-server@matronics.com [mailto:owner-commander-list-server@matronics.com] On Behalf Of Bill Hamilton Sent: Monday, 28 April 2008 9:03 PM Subject: RE: Commander-List: Survey Commanders Folks, To add a little to what Richard has said, and as a result of having been a long standing member of the CASA Standards Consultative Committee. Post WWII, a lot of work was done on fatigue in Australia, as the actual life of an individual airframe varies enormously, depending on the accumulation of fatigue damage, physical damage and corrosion damage. This included a rig test to destruction of 100 sets of new P-51D wing sets (left over after Korea), and this resulted in the "bell" curve used, to this day, for likely fatigue life distribution in aluminium structures. A desire to "lead the world" can be very expensive, if not very carefully managed, and to say that some "over-reacted" is an understatement, at great expense to many of us. However, the professional engineers of the day were not entirely unjustified. Australia's "good weather" produces a lot of heat turbulence, often well beyond design assumptions, as fitting a wide variety of GA, commuter and military aircraft with recording "fatigue meters" has shown. For a while, (and just for my own interest) I had a recording G meter mid-ships under floor in AT-28D, 51-3588. It was instructive to compare the tell-tale needle on the instrument panel G meter, and the recorder. The panel meter always under-recorded peak G, and of course gave no measure of duration. A number of in-flight break-ups of airline aircraft, including 3 Vickers Viscounts, spurred the efforts. To add to the mix, until 1998, Australia had its own design and certification rules, which, in the case of Aero-Commander, resulted in the certification of aircraft at higher gross weights than the factory/FAA, the higher weight certification included a spar strap. When the (now) well known problems of the cold bent spar extrusions surfaced, the AD spar straps were based on the existing Australian certification. One of the reasons then Department of Civil Aviation, DCA, took such a detailed interest, was the fact that they had a fleet of Aero-Commander, various models over the years. Richard's aircraft was delivered new to DCA. The last models their successors used was the Commander 1000 (695A), one has just changed hands in US. The problems of the cold bent extrusions at the wing/body point is well understood, the management by AD has been effective. The problem of dissimilar metal corrosion in spar caps is (now) well understood, but is/was a serious issue. The problems of off spec . material has no answer, it must be replaced. As all our aircraft get older, the results of corrosion becomes increasingly important, if you have never found any, you haven't looked hard enough - with the possible exception of Richard's aircraft, all the DCA/DOA aircraft were ordered with US MilSpec corrosion protection, with all airframe components chromate primed or anodised before assembly, with all drilled fastener holes treated to a brush of primer before "wet" riveting. As FAA produce "ageing aircraft" programs (Cessna SIDs) you will find a remarkable similarity between the inspection hours nominated, and the long standing Australian fatigue life/spar replacement ADs for C402 etc. Indeed, some of the new FAA/Cessna figures are marginally less than the Au AD. As we have pulled apart a few 402 for the SIDs, we have found some scary stuff. There are some very high hour airframes in Australia, when Cessna published the retirement life for the Conquest of 22,000 hours, I doubt they thought it would have had much effect. In Australia, 9 aircraft were grounded. If you have a look at the evolution of FAR 23 structural design standards, you will see the increasing attention to fatigue life, from memory, the Piper Tomahawk was the first aircraft certified after the first FAR 23 amendment to include fatigue justification, hence the wing life. Take the AC structural ADs very seriously, none are unjustified. Having said that, look at the Australian AD Richard put up, the life limits are two or three times the equivalent for most Cessna /Piper, that's telling us something. Neither of the two in-flight breakups of AC-500U or S appears to be fatigue related, being symmetrical downward bending failures just outboard of the engine nacelles. CASA (compared to FAA) is a problem, there have been some good changes in the senior management in the last two years, including several very competent people from the "Eastern Pacific Rim", but it takes a long time to turn the ship of state around. Cheers, Bill Hamilton From: owner-commander-list-server@matronics.com [mailto:owner-commander-list-server@matronics.com] On Behalf Of Richard & Jacqui Thompson Sent: Monday, April 28, 2008 4:37 PM Subject: RE: Commander-List: Survey Commanders Before you go Gulp. Understand that CASA makes your FAA look totally professional. This paper was written by an academic and as history has proved we have very strong airplanes. Take note that the wing is essentially a fail safe design. If it was not then a whole lot more airplanes would have crashed. One classic example in the report is the case of ZK-BWA and the pictures. What was not explained was that this aircraft had been badly damaged previously and not repaired correctly. The other problem is that a lot of the corrosion found in Aussie aircraft was due to the fact that they had been used in low level coastal work and really had not been looked after. This paper also ends in about 1995. I believe that in the 1999 the FAA had Twin Commander almost re certify their wings at great expense, destroying numerous airframes. Strangely enough they passed with flying colours. (which must have pissed the FAA off no end). Even our wonderful CASA went on to their 8th amendment of their AD on spar life http://www.casa.gov.au/airworth/airwd/ADfiles/under/ac/AC-066.pdf . I believe that a lot of accidents and especially in flight break ups have had a lot to do with the airframe being stressed way beyond its limits, usually in foul weather. You just have to do little thinking looking at the size of the things tale and then imagine the loads it has to take especially if you don't go with the flow and try to manhandle it in turbulence. You can break anything if you try hard enough. Cheers Richard -----Original Message----- From: owner-commander-list-server@matronics.com [mailto:owner-commander-list-server@matronics.com] On Behalf Of nico css Sent: Monday, 28 April 2008 10:57 AM Subject: RE: Commander-List: Survey Commanders _____ From: owner-commander-list-server@matronics.com [mailto:owner-commander-list-server@matronics.com] On Behalf Of mike floyd Sent: Friday, April 25, 2008 2:10 PM Subject: RE: Commander-List: Survey Commanders Read this: http://www.casa.gov.au/airworth/papers/aerocommander.pdf _____ From: WINGFLYER1@aol.com Subject: Re: Commander-List: Survey Commanders I have a 680. What caused the spars to break? _____ Need a new ride? Check out the largest site for U.S. used car listings at AOL Autos . " target=_blank>http://www.matronics.com/Navigator?Commander-List p://forums.matronics.com blank>http://www.matronics.com/contribution _____ Express yourself wherever you are. Mobilize! href="http://www.matronics.com/Navigator?Commander-List">http://www.matron ic s.com/Navigator?Commander-List href="http://forums.matronics.com">http://forums.matronics.com href="http://www.matronics.com/contribution">http://www.matronics.com/c http://forums.matronics.com http://www.matronics.com/contribution http://www.matronics.com/Navigator?Commander-List http://forums.matronics.com http://www.matronics.com/contribution ________________________________ Message 5 _____________________________________ Time: 03:02:03 PM PST US From: Craig Kennedy Subject: Re: Commander-List: Survey Commanders When I had my pre-purchase inspection done on 747H I was told the dye penetrant inspection was no longer valid and that the spar had to be xray's or sonigramed? Further,that the dye itself was found to be causing corrosion. Anybody heard this story. This was all done in October of last year. Craig WINGFLYER1@aol.com wrote: Ron, Thank you very much. I had the spars dye penetrated about a year and a half ago prior to buying the airplane and everything checked out o.k. Again thank you very much and if you have any other advice,I would appreciate hearing from you. Gil --------------------------------- Need a new ride? 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