747-400 spoiler panels
 

Just a bit confused: I have a company manual that states that "the four inboard spoiler panels operate as in-flight speedbrakes" and a Boeing manual which states that the inboard spoiler is ground only.

I bet the Boeing one is right, but does any have a definative answer?

There are 6 spoiler panels on each wing.

The outer 5 function as spoilers in conjuction with ailerons to provide roll control.

The 4 inboard panels function as speedbrakes.

All 6 function as ground spoilers.

Do you mean the 4 inboard "flight spolier" panels ie panels 2-5 or....

Re: 747-400 spoiler panels
 

The spoiler control system supplements the ailerons in providing lateral control of the airplane about the roll axis. There is a total of 12 spoilers of which 10 are flight spoilers and 2 are ground spoilers. Only the flight spoilers are used with the spoiler control system. However, the flight spoilers are used with the ground spoilers in the speed brake control system for speed brake operation. The spoilers are numbered 1 thru 12 from left to right. The four outermost spoilers on each wing are identified as outboard flight spoilers. The next spoiler on each side, No. 5 and 8, are identified as inboard flight spoilers. The two remaining spoilers, No. 6 and 7, are ground spoilers.

The speed brake control system is used to raise the spoiler panels to increase drag and reduce lift in flight and during rollout. There are twelve spoiler panels numbered 1 thru 12 from left to right. The ten outboard panels are called flight spoilers and the two inboard panels are called ground spoilers. Spoilers 3 thru 10 are used as speed brakes in flight. All spoilers are used as speed brakes during rollout. All spoilers are hydraulically powered and mechanically controlled.

The speed brake control system consists of a speed brake control lever, a speed brake lever lock, a speed brake drum mechanism, an automatic speed brake actuator, a speed brake sequence mechanism, a ground spoiler control valve, 2 ground spoiler control packages, and 2 ground spoiler panels. The system also uses the ten flight spoiler panels and drive components of the spoiler control system.

Re: 747-400 spoiler panels
 

Ahhhhh...

I think I've got it now.

I got a bit confused because panels 6 & 7 which are "ground spoilers" are also used inflight :confused:

Many thanks.

Pen

Re: 747-400 spoiler panels
 

...but only as speedbrakes, not as spoilers. :8