Very light jets Performance Class?
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Very light jets Performance Class?
There are some definitions of Performance Classes A and B floating around EASA legislation that do not match the applicability set out in CS25 (Amendment 21) and CS23 (Amendment 5) and this is creating confusion in my simple mind which persists in thinking CS.25 = Class A, CS.23 = Class B (quite possibly incorrectly). I look at EASA type certificates and I find jets below 5700 kg certified under CS.25 (although this is outside the applicability stated in CS.25 I can live with this) and their type certificates all clearly state 'Performance Class A', which is what I would expect. When however VLJs are certified under CS.23 or equivalent there is no corresponding Performance Class given, it just says 'normal, utiliy' . Normal, utility is a CS.23 category and this wouldn't indicate the Performance Class unless CS23 = Performance Class B is a rule. Going against this is a definition in the front of EU-OPS which says that 'Performance class A aeroplanes’ means multi-engined aeroplanes powered by turbo-propeller engines with an MOPSC of more than nine or a maximum take-off mass exceeding 5 700 kg, and all multi-engined turbo-jet powered aeroplanes; So by that definition even VLJs certified under CS.23 would be Class A, but why doesn't the type certificate say that?
I think the answer to my confusion will be found if I can determine whether VLJs certified under CS.23/FAR.23 (such as the CJ) are actually operated to Performance Class B rules in Part.CAT or to Performance Class A rules but I can find no document which will confirm this. Of course the criteria in CS.23 for high speed multis are very similar to CS.25 so its not always easy to see in practice when you look at the data in the AFM. I look on the type certificate - its not there, maybe it is in the Operations Manual? Can anyone help me with definitive information, please?
I think the answer to my confusion will be found if I can determine whether VLJs certified under CS.23/FAR.23 (such as the CJ) are actually operated to Performance Class B rules in Part.CAT or to Performance Class A rules but I can find no document which will confirm this. Of course the criteria in CS.23 for high speed multis are very similar to CS.25 so its not always easy to see in practice when you look at the data in the AFM. I look on the type certificate - its not there, maybe it is in the Operations Manual? Can anyone help me with definitive information, please?
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Hi Alex,
I think some CJ owners/operators would be very upset to have them described as VLJs since they look down their noses at the likes of Eclipses!
Seriously though, Looking at the TCDS for the CJ, under EASA Certification Basis Paragraph 3 - Special conditions you find buried in there:
performance, including takeoff, takeoff speeds, accelerate-stop, takeoff path,takeoff distance and takeoff run, takeoff flight path, climb one engine inoperative, landing, balked landing,climb
So they have been required to do the performance to CS-25 standards.
The identical wording also appears in the FAA TCDS, so it is not a condition imposed by EASA. Certainly i remember the AFM saying performance is to Part 25 standards long before EASA was thought of.
Hope that helps!
I think some CJ owners/operators would be very upset to have them described as VLJs since they look down their noses at the likes of Eclipses!
Seriously though, Looking at the TCDS for the CJ, under EASA Certification Basis Paragraph 3 - Special conditions you find buried in there:
performance, including takeoff, takeoff speeds, accelerate-stop, takeoff path,takeoff distance and takeoff run, takeoff flight path, climb one engine inoperative, landing, balked landing,climb
So they have been required to do the performance to CS-25 standards.
The identical wording also appears in the FAA TCDS, so it is not a condition imposed by EASA. Certainly i remember the AFM saying performance is to Part 25 standards long before EASA was thought of.
Hope that helps!
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Thank you! Apologies for the inappropriate classification. I see the special conditions, but everything you quote is covered in CS.23 for high speed multi-engine aircraft, its very similar to CS.25.
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One indication might be from the obstacle clearance criteria. With Class B the engine is not assumed to fail until visual reference is lost, with Class A an engine failure is assumed at VEF and the whole net take-off flight path is engine out. If a CJ has a two segment vertical profile it would be Class B.
