Originally Posted by
JABBARA
Fuel Penalty application is crystal clear but weight is not. I am not mentioning FMS calcualtion, I am talking about planning calculation. How to use weight penalty for planning purpose? Adding CDL penalty weight to actual weight is not a solution, That only helps to figure out what will be the capability of gross ceiling with this CDL penalty, which new gross ceiling is always less than the actual weight. But this has "NO RELATION" with NET CEILING. This calculation never gives an idea about driftdown NET CEILING path and NET CEILING VALUE, therefore we may not be aware whether this new NEt CEILING path and vaue is conflicting with enroute terrain/obstacles or not.
The net flight path data must be in your AFM (or approved supplement of) because it is the law:
b) Each Airplane Flight Manual must contain the performance information computed under the applicable provisions of this part.......25.123. En route flight paths.
The one-engine-inoperative net flight path data must represent the actual climb performance diminished by a gradient of climb of 1.1 percent for two-engine airplanes [etc]
Fuel Penalty application is crystal clear but weight is not. I am not mentioning FMS calcualtion, I am talking about planning calculation. How to use weight penalty for planning purpose? Adding CDL penalty weight to actual weight is not a solution,
Nobody is saying to add weight. You determine the enroute limit weight using the AFM performance data (for net flight path, it must be there). But you won't be able to achieve that performance given the extra drag of the missing item, so you reduce actual weight by the amount stated in the CDL and your net flight path will still be okay. I don't understand why that is not clear for you.