1900d Vmcg?
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1900d Vmcg?
Gday All,
Was just wondering if anybody could tell me if the 1900D has a VMCG. I know this forum is predominantly frequented by heavy metal drivers but any info would be much appreciated.
cheers
Was just wondering if anybody could tell me if the 1900D has a VMCG. I know this forum is predominantly frequented by heavy metal drivers but any info would be much appreciated.
cheers
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All multi eng aircraft (except C/L thrust) will have a VMCG published, as dont fly the 1900 I couldnt tell you what speed it is, but it will have one.
Last edited by Squealing Pig; 7th Sep 2006 at 22:21. Reason: Crap spelling after several beers
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It is possible that there is no value published; if the OEM was able to convince the regulator that the value was so low as to never be limiting, they may not have required a specific value to be determined. Though in that case I would expect a statement that Vmcg was never limiting to be made instead.
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FAR-23 commuter aircraft aren't required to publish Vmcg as long as a Vmc is published. If so, V1 and Vr must be higher than Vmc...no reduced V1 possible. The designer may decides to certify the aircraft with a Vmcg (to reduce runway requirements on wet / contaminated runways), but obviously has not for the B1900.
All FAR-25 aircraft must publish Vmcg / Vmca.
All FAR-25 aircraft must publish Vmcg / Vmca.
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Actually, if you wanted to read the regs VERY pedantically, the same actually applies to Part 25 certification ... 25.149 requires that you "establish" 'VMC', 'VMCG' and 'VMCL'; 25.1513 requires that "The minimum control speed VMC determined under Sec. 25.149 must be established as an operating limitation."; and 25.1583 "Operating Limitations" requires that "any other airspeed limitations necessary for safe operation must be furnished".
So we have to calculate Vmcg and Vmcl, but we only have to 'furnish' 'VMC'(a). Of course, having calculated them and used them in the performance calcs, it would seem pointless NOT to publish them.
I believe, also, that 'furnish' doesn't have to mean 'provide a number' - I think one of our types has a statement that Vmca is NEVER limiting, and in fact I don't think a Vmca value was ever determined during certification - it was just shown to be lower than any practical speed. (I'm going from memory, and would have to check to be certain)
So we have to calculate Vmcg and Vmcl, but we only have to 'furnish' 'VMC'(a). Of course, having calculated them and used them in the performance calcs, it would seem pointless NOT to publish them.
I believe, also, that 'furnish' doesn't have to mean 'provide a number' - I think one of our types has a statement that Vmca is NEVER limiting, and in fact I don't think a Vmca value was ever determined during certification - it was just shown to be lower than any practical speed. (I'm going from memory, and would have to check to be certain)
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Point taken, but in regards to the original B1900 question:
Being a FAR-23 Commuter certificed aircraft, we can conclude that without a published Vmcg (only Vmc), V1 can never be set lower than 1.05 x Vmcg, and subsequently Vr never lower than V1.
Hence, no reduced V1 for the B1900 no matter how low the braking action might get?
Isn't that what the original question aimed to adress?
Being a FAR-23 Commuter certificed aircraft, we can conclude that without a published Vmcg (only Vmc), V1 can never be set lower than 1.05 x Vmcg, and subsequently Vr never lower than V1.
Hence, no reduced V1 for the B1900 no matter how low the braking action might get?
Isn't that what the original question aimed to adress?
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Point taken, but in regards to the original B1900 question:
Being a FAR-23 Commuter certificed aircraft, we can conclude that without a published Vmcg (only Vmc), V1 can never be set lower than 1.05 x Vmcg, and subsequently Vr never lower than V1.
Hence, no reduced V1 for the B1900 no matter how low the braking action might get?
Isn't that what the original question aimed to adress?
Being a FAR-23 Commuter certificed aircraft, we can conclude that without a published Vmcg (only Vmc), V1 can never be set lower than 1.05 x Vmcg, and subsequently Vr never lower than V1.
Hence, no reduced V1 for the B1900 no matter how low the braking action might get?
Isn't that what the original question aimed to adress?
I'd say that the absence of a published Vmcg means that V1 can never be set lower than 1.05*VMC, assuming that Raytheon/Beech never established a Vmcg per 23.149(f) and so the option in 23.51(c)(1) isn't available.
However, it's possible that they DID establish a Vmcg, and that they have set V1 based upon that Vmcg, but have not published it in the manual per a strict/pedantic reading of 23.1513 (similar logic as the part 25 pedantry I described). What it means in that case is that the operator doesn't have any data which would permit setting a lower V1, since they don't know if they are VMC or Vmcg driven. But, in the absence of any guidance in the flight manual, you'd have no performance data for a reduced V1 anyway, so would be operating outside the 'book' with regard to e.g. distances. It's the "applicant" who selects V1, not the operator.
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I'd say that the absence of a published Vmcg means that V1 can never be set lower than 1.05*VMC, assuming that Raytheon/Beech never established a Vmcg per 23.149(f) and so the option in 23.51(c)(1) isn't available.
