Failure - Interactions

Much more on this case  --  In-progress,   standby:


C.A.B.'s  AAR  for B707  N712PA /  3Feb59

pdf is short,  772KB



New York Times,    March 15, 1959,   p86:

"the airline has used only supervisory personnel to fly its jet  . . .

"Pan Am Training . . .  regular line pilots . . . dispute settled last month."

Testimony,   Flight Engineer,   George  Sinsky,


Sound of Mach Warning,  

      G-load,   pinned-to-seat,  

               unable to raise arms  ...



Horizontal Stabilizer  TRIMMED  full-nose-down ...

       manually  cranked Horiz-Stab'  to normal position,  

Testimony of   Sam Peters,    

           who sat as  co-pilot (right-seat, SIC)


22z Heading change, to LEFT,  "posted" by Nav'.

Autopilot Turn Knob -- turn OK.

Buffeting,   caused panel light failure --  [rolled  right]...

     Captains Horizon had tumbled  ... 

Co-Pilot  used  Control Wheel -- left aileron,  and Rudder,

           G-loads,   "immobilized",   severe  buffeting,

                 Captain Lynch returned ... cut power ...


Horizontal Stabilizer  TRIM  ... position showed  nose-down  ...

   F/E  manually  cranked  Horiz-Stab TRIM

          (cranked  Trim-Wheel )   ...    pull-out ...  climb  ...



Captain Waldo Lynch,   testimony:


Out-of-Seat,   Out-of-Cockpit,

    increased NOISE level,

          G-forces  increasing,  


Lynch  re-entered cockpit,

   "slammed"  Thrust Levers to IDLE,

      gyro-horizon  had tumbled,


        Airspeed  past  400 KIAS,


           Altitude  passing  17,000-feet,


              Electric  Pitch-Trim  thumb-switch  INOP'

Prior history of  Autopilot  trip-OFF.


Other pilots had not reported --  few  "disconnects"

had been reported before the mishap.


After the mishap-dive,  on Feb' 6th,  

   pilots entry in aircraft logbook:  

       another  disconnect,

                      with no warning-light.

Uncertainty about status of Autopilot, 

just prior to  the   INITIAL   upset:

Not  ENGAGED?     Disconnected?


No aural nor visual annunciation

that the Autopilot had Disengaged.

London  to  Gander,  CRZ,  

35,000-feet,  0.82 Mach,

OAT -55C,   

GWt 195,000  (pounds),  

 ~ 2200 Z . . .  

Aviation Week,  March 23, 1959,  p 37-8:

On  Mar' 11th  and 12th 1959,

C.A.B.  heard  "depositions"  in  New York,

with later depositions  in  Seattle and L.A.

New York Times,   Feb' 5th, 1959,   p20:

Night, step-climbed to 35,000-feet,  over storm, 

CRZ,   PIC-out-of-seat,  

standing in forward passenger-cabin,

shaking,    thrown to floor,

crawled back to pilot's cockpit-seat,  recovered ... 

Pan Am   /   3Feb59,    B-707-121,    N712PA,  

night  Cruise,    FL350,  

North Atlantic,  west-bound,   40W,  

a pilot-out-of-cockpit,    subtle roll upset,

spiral-dive,    recovery

high-G  pull-up    near 6000 feet.

. . . during the captain's absence from the cockpit  

the autopilot disengaged   and

the copilot did not detect  . . .  

a steep  nosedown   right spiral. . . .  

it entered this maneuver  gradually  without any abrupt movements. . . .  

during  the hours of  darkness,  

the autopilot  disengage   warning light   … failed . . . 

[C.A.B.'s AAR,  p8,   "Analysis"].

Witkins, R.    "Troubles Noted On Auto-Pilots -- Inquiry ... Jetliner's Dive ...",                      

New York Times,  March 13, 1959,  p58.      

"... matters that might seem inconsequential to crewmen ...  shop had found the auto-pilot disconnecting with greater frequency than previously reported ..."

Rolled   Wings-level,


    heavy  pounding  and   buffet  at  6000-feet,


        zoomed  nose-up,    climb,  

             airspeed  decreasing,

                control   by  9000-feet    . . . 



   After   recovery,   "heavy"  right rudder needed . . .