With respect to the A320 QRH - In Flight Performance landing distance ( both without and with failures) is anyone really aware whether these figures include an additional safety margin or are they actual figures?
I did hear a strong opinion in the past that these are actual figures but after some search I could not locate anywhere officially such assertion.
The QRH landing distance is defined as
LANDING DISTANCE (LD)
The LD is the landing distance calculated in-flight (also called in-flight landing distance). It is based on the landing performance model elaborated by the Takeoff and Landing Performance Assessment / Aviation Rulemaking Committee (the TALPA/ARC committee was mandated to find an industry consensus and produce recommendations for new regulation on landing performance assessment). LD wants to be more representative of the landing technique followed by line pilot and so more representative of daily operations.
Your airline should deem if there’s any extra factor (we are recommended to add an extra 15%). The LD above will be more than the Actual Landing Distance which is used to work out the Required Landing Distance at dispatch (e.g. RLD dry =ALD/0.6)