Expert: Capt Paul - 11/20/2006

Question
Dear Sir,

I am working in one of our airlines in our country which is using a Airbus A319 and A320 aircraft. How do you interpret the limitation codes on the takeoff limitation chart, like what does 3/4, 4/6, 3/6 etc...mean?

Our Limitation Codes are the following:

1 - 1st Segment
2 - 2nd Segment
3 - Runway Length
4 - Obstacles
5 - Tire Speed
6 - Brake Energy
7 - Max Weight
8 - Final T/O
9 - VMU

Looking for your reply.

Thank you.

Jason


Answer
It’s an explanation of why the MTOW may be limited.

To determine the regulatory takeoff weight for takeoff planning, it is mandatory to provide pilots with data, which enable quick calculations of the Maximum Allowed Takeoff Weight and associated speeds.

These documents are referred to as “Regulatory Takeoff Weight” Charts (RTOW). The charts are generated for each runway, and are produced for different takeoff conditions at the convenience of the airline.  I.e.:  temperature, wind, QNH, flap setting, runway status, inoperative items.

The charts provide the:
Maximum Takeoff Weight (MTOW)
Takeoff speeds (V1,VR,V2)
Limitation code
Minimum and maximum acceleration heights.



Example: MTOW and speeds determination

Takeoff from Paris, Runway 08

Slat/Flap configuration: 1+F

OAT = 24ºC

Wind = Calm

QNH = 1013 hPa

Air conditioning: Off

Runway state: Dry


RESULT

MTOW = 73.6 tons

V1 = 149 Kt, VR = 149 Kt, V2 = 153 Kt

MTOW limited by: second segment and obstacle (2/4)