I had a look at some Boeing figures when the two Luxair charters took place and I came up with a full pax payload maximum range with reserves of about 800 nm for aircraft without the de-rated engines. It looked as if LDR was a bit marginal for SEN's 1,604m LDA and probably a non-starter if the runway should be declared WET.
Maybe a 738 driver out there could compute more accurate figures for SEN's runway.
Edit: I'm sure Ryanair's aircraft could not operate commercially from SEN.
Last edited by Expressflight; 13th Dec 2015 at 17:06.
Reason: clarification