Airspeed Limitations

Six speeds bound everything this aeroplane is allowed to do. The limitations table prints each of them twice — once calibrated, once indicated — and it is the indicated column that matches what you will read off the instrument in flight.

At a glance

• V_NE, never exceed145 KCAS / 149 KIAS
• V_NO, maximum structural cruising108 KCAS / 111 KIAS
• V_A at 1670 lbs101 KCAS / 104 KIAS
• V_A at 1500 lbs96 KCAS / 98 KIAS
• V_A at 1350 lbs91 KCAS / 93 KIAS
• V_FE, maximum flap extended87 KCAS / 85 KIAS
• Maximum window open speed139 KCAS / 143 KIAS

The two speeds that bound cruise

Never exceed speed is 149 KIAS, and its remark admits nothing: no operation whatever justifies going past it. Maximum structural cruising speed is 111 KIAS, and its remark is conditional: do not exceed it except in smooth air, and then only with caution.

Between 111 and 149 knots indicated you are inside the band the aeroplane may be flown in only when the air is smooth. Above 149 there is no condition that makes it permissible.

Manoeuvring speed falls with weight

Three weights, three speeds

• 1670 pounds: 104 KIAS

• 1500 pounds: 98 KIAS

• 1350 pounds: 93 KIAS

A lighter aeroplane has a lower manoeuvring speed, not a higher one. That is the direction students most often get backwards, and the three rows above are worth memorizing as a set rather than remembering only the maximum-weight figure.

NOTE — The remark the limitations table attaches to manoeuvring speed is that full or abrupt control movements must not be made above this speed.

Flaps and windows

Maximum flap extended speed is 85 KIAS, with the remark that this speed is not to be exceeded with flaps down. Maximum window open speed is 143 KIAS, with the corresponding remark for windows.

NOTE — Maximum flap extended speed is the one row of this table where the calibrated figure, 87 knots, is higher than the indicated figure, 85 knots — the reverse of every other row. Both columns are reproduced exactly as the handbook prints them, and the 85 KIAS figure agrees with the top of the airspeed indicator's white arc.

Check yourself

• What are V_NE and V_NO in indicated airspeed, and how do their two remarks differ?

• State manoeuvring speed at each of the three weights tabulated.

• Does manoeuvring speed rise or fall as the aeroplane gets lighter?

• What is the maximum speed with the flaps extended, and what is the maximum speed with a window open?

Study aid — always fly your aircraft's current AFM/POH.