The law of unintended consequence
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The law of unintended consequence
In a recent conversation (with a clever person), the relative merits of the EC155 and BA139 were being discussed. I postulated that the size of the engines in the AB139 - 1800shp with growth potential to 2400shp (same basic engine used in the AB609), would provide engine failure accountable performance at all but the highest altitudes.
Yes said the clever person but the running costs of such installed power are a serious downside when compared to the EC155 which has (almost) the same payload space with much lower DOCs.
We progressed to growth potential for the AB139, ah he said but the growth potential will erode the excellent performance down to the average - economics will be the final arbiter of the end result. Yes said I but the economics of a potential accident must be somewhere in the equation - stalemate.
OK clever person, said I, why is it then that the smart little twins (B427, A109E, EC135, 902 - sorry if I have missed out your little beauty) are fast reaching the stage when OEI HOGE is possible (at MUAM sea level ISA plus something).
Ah said he appoaching the check-mate stage, these twins are built to the FAR/JAR 27 Certification code which limits the growth weight to 7,000lbs. Therefore, any increase in installed power or gear box improvements can be taken as an increase in performance.
Ah said I, a win for the law of unintended consequence - and I am a little cleverer than I was.
Yes said the clever person but the running costs of such installed power are a serious downside when compared to the EC155 which has (almost) the same payload space with much lower DOCs.
We progressed to growth potential for the AB139, ah he said but the growth potential will erode the excellent performance down to the average - economics will be the final arbiter of the end result. Yes said I but the economics of a potential accident must be somewhere in the equation - stalemate.
OK clever person, said I, why is it then that the smart little twins (B427, A109E, EC135, 902 - sorry if I have missed out your little beauty) are fast reaching the stage when OEI HOGE is possible (at MUAM sea level ISA plus something).
Ah said he appoaching the check-mate stage, these twins are built to the FAR/JAR 27 Certification code which limits the growth weight to 7,000lbs. Therefore, any increase in installed power or gear box improvements can be taken as an increase in performance.
Ah said I, a win for the law of unintended consequence - and I am a little cleverer than I was.
Join Date: Dec 2001
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The fact that the EC135 is out there flying means it meets all the requirements, or has demonstrated equivalent safety in some areas where the requirements are not exactly applicable.
It appears you may be fishing for something - do you believe that it doesn't meet all the requirements?
It appears you may be fishing for something - do you believe that it doesn't meet all the requirements?
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Join Date: May 2002
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Heard a rumour that it does not meet the JAR/FAR 27 Crashworthiness requirements. The report into the Strathclyde Police Helicopter crash may raise some issues regarding this. Having seen the wreckage at Farnborough, it raises the question as to what the outcome may have been had the airframe rolled more than 90 degrees during or after impact.
