where—  F$_{N}$ = Fuel used for the flight under consideration (i.e. flight $_{N}$) determined using Block-off/Block- on Method (in tonnes);  T$_{N}$ = Amount of fuel contained in aeroplane tanks at Block-off for the flight under consideration  i.e. flight $_{N}$ (in tonnes); and  R$_{N}$ = Amount of fuel remaining in aeroplane tanks at Block-on of the flight under consideration  i.e. flight $_{N}$ (in tonnes).  6. —(1) For flights with a fuel uplift, unless the subsequent flight has no uplift the aeroplane  operator must use the following formula to compute fuel use according to the Fuel Uplift  Method( a )—  where—  F$_{N}$ = Fuel used for the flight under consideration (i.e. flight $_{N}$) determined using fuel uplift (in  tonnes); and  U$_{N}$ = Fuel uplift for the flight considered, measured in volume and multiplied with a density value  (in tonnes)( b ).  (2) For flight(s) without a fuel uplift (i.e. flight $_{N+1}$, …, flight $_{N+n}$), the aeroplane operator must  use the following formula to allocate fuel use from the prior fuel uplift (i.e. from flight $_{N}$)  proportionally to block hour—  Fuel Uplift  BH Fy = Uy * N | BHy + BHy+i + + BHyzn BHysı Fy+ı = Un * | Er + BHyzı + + BHysn BHy+n | Fen = Un * lx + BHys, + + Bäyın where—  F$_{N}$ = Fuel used for the flight under consideration (i.e. flight $_{N}$) determined using fuel uplift (in  tonnes);  F$_{N+1}$ = Fuel used for the subsequent flight (i.e. flight $_{N+1}$) determined using fuel uplift (in tonnes);  F$_{N+n}$ = Fuel used for the follow-on flight (i.e. flight $_{N+n}$) determined using fuel uplift (in tonnes);  BH$_{N}$ = Block hour for the flight under consideration (i.e. flight $_{N}$) (in hours);  BH$_{N+1}$ = Block hour for the subsequent flight (i.e. flight $_{N+1}$) (in hours); and  U$_{N}$ = Fuel uplift for the flight under consideration (i.e. flight $_{N}$) (in tonnes)( c );  BH$_{N+n}$ = Block hour for the follow-on flight (i.e. flight $_{N+n}$) (in hours).  ( a ) See Attachment C-7 in Volume IV of Annex 16 to the Chicago Convention for a process diagram for monitoring fuel use by  flight using the Fuel Uplift Method.  ( b ) See article 28 for requirements on fuel density values.  ( c )  Fuel uplift is determined by the measurement by the fuel supplier, as documented in the fuel delivery notes or invoices for  each flight.  48