Can throttle control be considered as a primary flight control?

My flight instructor asked me if throttle can be considered as a primary flight control?

14 CFR 23.673 - Primary flight controls defines primary flight controls as:

Primary flight controls are those used by the pilot for the immediate control of pitch, roll, and yaw.

While a throttle could be used to effect changes in aircraft attitude (depending on configuration and other factors), the effect could hardly be called immediate/direct. So, throttle could hardly be called a primary flight control; and as @Ron pointed out, there are gliders.

Note: I'm aware that aircraft have been controlled solely using throttle. But it is an exception rather than the norm.

• You mean you don't have thrust vectoring engines? – Joshua Jan 10 '17 at 22:52

Yes, according to wikipedia, the throttle is considered to be a primary flight control, along with

a control yoke (also known as a control column), centre stick or side-stick (the latter two also colloquially known as a control or joystick), governs the aircraft's roll and pitch by moving the ailerons (or activating wing warping on some very early aircraft designs) when turned or deflected left and right, and moves the elevators when moved backwards or forwards rudder pedals, or the earlier, pre-1919 "rudder bar", to control yaw, which move the rudder; left foot forward will move the rudder left for instance. throttle controls to control engine speed or thrust for powered aircraft.

It is considered to be a primary flight control because it makes a big difference to the aircraft, a plane with no throttle can't fly!

• "a plane with no throttle can't fly" Except pretty much every glider... – Ron Beyer Jan 10 '17 at 14:30
• @RonBeyer I guess so, I was just focusing my answer on powered aircraft – anonymous Jan 10 '17 at 15:08
• While they say that Wikipedia is pretty reliable these days, I'd take aeroalias' quoting of CFR as a higher authority. Of course, OP doesn't specify which country he's in, so US-FAA may not have authority, but I'd imagine that's a pretty standardized definition. – FreeMan Jan 10 '17 at 15:58
• @RonBeyer: Except for a bungee launch, even gliders need a throttle to get into the air. It cannot be wished away completely. – Peter Kämpf Jan 10 '17 at 16:57
• according to Wikipedia I'm sorry, Wikipedia is wrong. It is useful, but has never been an authoritive source of information. (Someone here should go and edit it!) – kevin Jan 10 '17 at 17:15