Dear forum users,one question that I have a hard time to find a good answer to:What category (A, B, C, D) aircraft are the different versions of the 737NG?What about the versions flying with the short field package?Is the category a fixed aircraft property or does it depend on the final approach speed of the acctual configuration the aircraft is in?Many thanks for your answers.All the best,Ingo(Sorry, I can't afford the luxary to sign with my real life identity.)

According to pages 5.3 and 5.4 of the FCTM:737-600, 737-700: category C737-800 - 737-900ER: category C or D, depending upon the maximum landing weight

Is the category a fixed aircraft property or does it depend on the final approach speed of the acctual configuration the aircraft is in?

It's based on landing speed Vref at maximum gross landing weight and their initial approach speed.Category A aircrafts have a Vref of less than 90 KIAS and an initial approach speed between 90 and 150 KIAS (all helicopters and lighter aiplanes).Cat B have Vref between 90 and 120 KIAS and an initial approach speed between 120 and 170 KIAS (E120; AT42; AT72; B350; DHC8 and similars).Cat C Vref is between 121 and 140 KIAD with apprach speeds between 160 and 220 KIAS. (A320; B737;B757; CRJ7; C130; LR45 and similars).Cat D Vref is between 141 and 165 KIAS with app speeds between 185 and 220 KIAS (A330; A340; B744; B777; MD11).The Concorde was an exceptional case, because it's Vref was above 165 KIAS at MLW and it had very high approach speeds. Therefore, an especial category was created for him, Category E. Since the Concorde is retired, this category was abandoned.

In the US and countries that go by TERPS, Category C unless you're circling, then it's D.