safetypee, there's numerous explanatory material about landing performance and I don't intent to play a teacher here. However fact is RLD is applicable to dispatch ONLY whereas ALD is for in flight assessment. UK doesn't differ a bit from EU OPS all it says for contaminated RWY at the planning stage RLD is never lower than ALD wet. Application of additional safety margin, typically 15%, is recommended. If you ever used EFB you'd have seen 2 sections for landing performance one is for dispatch stating RLD and the other one for in flight showing ALD and they're shorter by bout 40%. I'll state it again there's NO EU OPS requirement to apply RLD in flight. TALPA rectifies that situation by creating guide line of a realistic ALD assessment thus increasing safety.
