We fly both types, both modded and non-modded. The restriction regarding T/O and descent is of course applicable to the unmodded, you're right. But that doesn't clarify the question. Both types have the restriction of 453 kgs on ground.
If the flickering light On T/O is the problem, why not set the pumps on before taxi like in the situation with the unmodded pumps (and fuel less than 2300 kgs), and turn them off before T/O?
And if it's the pumps going dry, why is that all of a sudden not a problem in the air? There we fly them until the LOW PRESS flickers and then turn them off.
CTR tank fuel isn't all that much cooler either from what I know.
Asked a technician today. Got lots of theories but no really good explanations there either
