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"We are the protagonists of our stories called life, and there is no limit to how high we can fly."

Type rated on A330, B747-400, B747, B757, B767, B737, B727. International Airline Pilot / Author / Speaker. Dedicated to giving the gift of wings to anyone following their dreams. Supporting Aviation Safety through training, writing, and inspiration.

Tuesday, January 9, 2018

Boeing 777 Trivia Challenge 3!

But First...
Last week's question: 

What  switches are normally left in OFF 
for normal operation?  

Instrument Source Selector Switches

The above picture displays the visual when the switches are "OFF"-- a normal condition and how we fly. In the OFF position, the system provides automatic instrument source selector switching in the event of a failure. Now, if you were to turn the switches on (as depicted below) the automatic switching would not occur. Therefore, we leave these switches in the OFF position. 

Trivia Challenge 3

In that the last two questions have gone unanswered
This is a super easy question: 

Boeing identified the Flight Control Modes of Operation as"
  • Normal
  • Secondary
  • Direct
However, they identified the Flap/Slat Modes of Operation as: 
  • Primary
  • Secondary
  • Alternate

The question is, why did Boeing keep the same terminology "Secondary" for both the Flight Control and Flap/Slat modes, but changed the terminology for the other modes?

Good Luck! 

Enjoy the Journey!
XOX Karlene 


  1. Doesn't Airbus use that terminology ? So that is why changed it. Normal flight in a Airbus is called primary and outside the limits it is called alternate flight?

    1. Actually Airbus has Normal Law, Alternate Law, and Direct Law. But...they are laws, not to confused with flap and slat modes. But they do use the term Alternate.

      The only reason Airbus could have anything to do with this is if Boeing decided to do just the opposite. Seriously, why do they have to name the same technology different?

      Wouldn't it be easier and better training transitioning between aircraft to use the same language?

      Thanks for your comment!!

  2. For the flight controls the normal mode and secondary use the same computers and components but in a simplified mode. DIRECT refers to the bypassing of the primary flight control computers, not the control to surface relationship in Airbus’s Direct law since in roll the 777 always has a direct control to surface relationship, and in pitch it has that in both secondary and direct modes.

    The flaps and slats use a Hydraulic system for primary movement and electric for secondary and alternate. They are separate drive motors. The alternate uses separate motor and separate flap/slat controls.

    In both systems the secondary attempts to operate the respective system similarly to the Normalmor/Primary mode but degraded in data input/ speed of operation.

    1. Thank you Bill. But the real question is the "language"... why "normal" versus "primary". Why not normal flight controls and normal flaps? Why not Alternate Flight Controls like Alternate flaps? The words they use between the two is the real question.


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