A310 Aerobatics

From:         Karl Swartz <kls@ohare.Chicago.COM>
Date:         01 Dec 92 13:54:54 PST
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The latest issue of Airliners (Winter 1992) has a fascinating article
on an incident with an Airbus A310.  Some tantalizing details of what
happened for the fans of leaving the pilot fully in control, but not
enough information to trace the incident any further.  In the hopes
that someone might know more (PLEASE post any relavent details, and of
course dicussion is welcome too), and perhaps to turn a few folks onto
a good magazine, here's the article, from Tailpieces:

A310 Aerobatics
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Following an autopilot-coupled go-around, the pilot attempted to
counteract the autopilot's programmed pitch-up by pushing forward on
the control column.  (In most circumstances pushing on the control
column disengages the autopilot but automatic disconnect is inhibited
in go-around mode.  The autopilot should be disconnected or a mode
other than go-around should be engaged through the FCU - Flight
Control Unit.)

As a result of the control inputs, the autopilot trimmed the stabil-
izer to -12 degrees (nose up) to maintain the go-around profile, but
the elevator was deflected 14 degrees (nose down).  After climbing
about 600 feet (to around 2,100 feet) the autopilot captured its
preselected missed approach altitude and disconnected as the go-around
mode was no longer engaged.  In the next 30 seconds, the grossly
mistrimmed A310 pitched up to 88 degrees and airspeed dropped to less
than 30 kt.  (The stall warning activated then canceled itself as the
airspeed fell below usable computed values and the autothrottle system
dropped off.)  At 4,300 feet, the A310 stalled, pitching down to -42
degrees while the pilot-applied control inputs showed full up
elevator.  Airspeed increased to 245 kt then the aircraft bottomed out
at 1,500 feet, pulled +1.7 g, then climed rapidly.

The second pitch-up reached 70 degrees followed by a stall 50 secondds
after the first.  The nose dropped to -32 degrees and airspeed rose to
290 kt and the aircraft bottomed out at 1,800 feet.  On the third
pitch-up (to 74 degrees), the A310 climed to 7,000 ft then stalled
again, about 60 seconds after the second stall.  This time airspeed
reached 300 kt in a -32 degree nose down attitude before the aircraft
leveled off at 3,600 feet.

The fourth pitch-up reached 9,000 feet but this time the crew's use of
thrust and elevator control (and very likely retrimming the stabilizer)
prevented a stall and the A310 leveled off at 130 kt.  Speed then
increased accompanied by another milder pitch-up to 11,500 feet where
control was eventually regained.

All aircraft systems operatedd in accordance with design specifica-
tions.  The reaction of ATC (the incident happened at Moscow) or the
passengers is not recorded.

--
Karl Swartz	|INet	kls@ditka.chicago.com		
1-415/854-3409	|UUCP	uunet!decwrl!ditka!kls
		|Snail	2144 Sand Hill Rd., Menlo Park CA 94025, USA
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