B757-Pilot_Induced_Oscillations

民航

B757-Pilot_Induced_Oscillations

 

游客，如果您要查看本帖隐藏内容请回复

民航

1
757 Pilot Induced
Oscillations (PIO)
Capt. Leon Robert
Chief Project Pilot, Boeing 757
Boeing Commercial Airplanes
May 2004
The Boeing Company W100.2
PIO
• Continue to get infrequent reports of oscillatory
events in the roll axis
– Usually on landing (“high gain” pilot task)
– Usually in light crosswinds
• Review Some Actions Already Taken
• Preview More Actions to Come
Why are we talking about this?
The Boeing Company W100.3
Agenda
• What is a Pilot Induced Oscillation (PIO)
• What causes a PIO
• What we have done already
• What we will be doing
The Boeing Company W100.4
What is a Pilot Induced Oscillation?
• National Research Council Definition:
– An inadvertent, sustained aircraft oscillation
resulting from a closed-loop interaction between
the aircraft dynamics and the pilot’s flight control
inputs in which the aircraft response becomes
substantially out-of-phase with the pilot input.
The Boeing Company W100.5
PIO – A Pilot’s Comments
• Pilot must be in the loop – trying to control the
airplane
– Open-loop control wiggling is not a PIO
• Pilot must be out-of-phase with the airplane
response
– Typically reported as “airplane going the wrong
way” or that something in the control system had
broken
• Event is usually precipitated by a “Trigger” event
– External Disturbance
– Inadvertent large pilot input
– Unanticipated airplane response to an input
The Boeing Company W100.6
Actions:
• Immediately stop control wheel input
• Go-around, if safe landing cannot be made
The Boeing Company W100.7
What We Have Done to Date
• 09/28/00 Fleet Team Digest Article
• 07/05/02 Operations Manual Bulletin
• 08/02/02 Flight Operations Technical Bulletin
• 11/05/02 Non-Normal Maneuver added to QRH
• 11/09/02 Fleet Team Conference
• 11/29/02 Flight Operations Symposium
• 05/10/04 Flight Operations Symposium
Flight Crew Awareness
The Boeing Company W100.8
What We Have Done to Date
• Vortex Generators on Flaps
– Service Bulletin on existing -200
– Production on -300
• Serve to smooth the rapid separation of airflow on
the flaps at small spoiler deflections
• Makes the roll response more linear, eliminating an
“unanticipated response” PIO trigger associated
with some crosswind landing conditions
Airplane Changes
The Boeing Company W100.9
Upcoming Actions
• Wheel Damper Installation
– Designed to increase the pilot force required to
make very large, very rapid wheel inputs
– Provides a tactile cue to the pilot that inputs
are becoming unnecessarily large and/or
fast
– Consistent with the Boeing cueing
philosophy
– Designed to not interfere with “normal” flying
Wheel Damper
The Boeing Company W100.10
Upcoming Changes
• Revised Wheel Force Rigging Procedure
– Boeing airplanes use artificial force-feel systems
to generate wheel forces
– Wheel feel systems include a center “detent” force
– Helps hold the wheel in neutral position
during unattended operation
– Provides a tactile cue to identify neutral
wheel
Wheel Detent Force
The Boeing Company W100.11
Wheel Force Rigging
• Some airplanes have higher detent forces than
others
• Excessive detent forces are potential PIO triggers
– Contributes to imprecision in rapid wheel inputs
– Potentially generating unanticipated airplane
response
• Revised rigging procedure will provide adequate
wheel centering and minimize the adverse trigger
effects
– Wheel centering on some airplanes may not be as
“crisp” as previously
The Boeing Company W100.12
Summary
• PIO’s are caused by an adverse interaction between the pilot
and the airplane dynamics
– Transport airplane dynamics are slow enough that pilots can
get out-of-phase
– The cycle can be broken by freezing the control inputs
– Published Info: Fleet Team Digest, Technical Bulletin, OMB,
SB, symposiums
• PIO’s are often precipated by “trigger” events
– Boeing has been aggressively eliminating potential triggers
– Vortilon installation
– Wheel damper installation
– Revised rigging procedures

979199501

CFM56-7 Starter Reliability

tonyblairer

很好的资料，谢谢分享

332356357

感谢楼主！！！！