Pilatus PC-12 Autopilot Disconnect Pilot Issues
Summary
TLDRThe video script discusses the recurring issue of autopilot disconnection in PC12 aircraft leading to loss of control during Instrument Meteorological Conditions (IMC). It reviews autopilot limitations, the NTSB report on a 2017 accident, and the importance of training for pilots to manage aircraft manually. The script also emphasizes the need for pilots to understand and quickly respond to autopilot disconnection, especially in turbulence, to prevent accidents.
Takeaways
- ✈️ The PC12 aircraft has a history of accidents related to autopilot disconnection and subsequent loss of control in Instrument Meteorological Conditions (IMC).
- 🔄 Autopilot disconnection on the PC12 can occur due to various limitations, including exceeding roll rates, pitch rates, or G-force limits, as well as brief stalls.
- 🚨 The autopilot system on the PC12 will disengage if it detects a stall, even a temporary one caused by turbulence, leading to a series of cockpit warnings.
- 🛠️ Pilots need to be familiar with the autopilot controls and limitations to manage the aircraft effectively, especially during single-pilot operations in IMC.
- 📚 A review of the autopilot's limitations and proper training is crucial for pilots to handle situations where the autopilot disengages.
- 👤 The 2017 NTSB report highlighted the pilot's loss of control due to spatial disorientation after an autopilot disconnection in moderate turbulence.
- 🔑 The PC12 features a big red autopilot disconnect button and a trim switch for managing the autopilot system during flight.
- 📈 The autopilot's pitch and roll rate limits are critical for pilots to understand to avoid disconnection during turbulence or aggressive maneuvers.
- 🛑 In the event of an autopilot disconnection, pilots must silence the cockpit warnings by pressing the autopilot disconnect button to focus on flying the aircraft.
- 🔄 Pilots transitioning to the PC12 should undergo professional training and maintain proficiency through annual training programs.
- 👷 For new or low-time pilots, flying with an experienced mentor in the PC12 is recommended to gain familiarity with the aircraft's automation and systems.
Q & A
What is the primary concern discussed in the video script regarding the PC12 aircraft?
-The primary concern is the autopilot disconnection issue on the PC12 aircraft, which has led to several accidents, especially in Instrument Meteorological Conditions (IMC), causing pilots to lose control of the aircraft.
How many PC12 accidents were mentioned in the 2019 Used Aircraft Guide due to loss of control in IMC conditions?
-There were six different PC12 accidents mentioned in the 2019 Used Aircraft Guide that were the result of loss of control of the aircraft in IMC conditions.
What is the significance of the autopilot disconnection in the PC12 aircraft?
-The autopilot disconnection in the PC12 can be particularly challenging for single pilot operations in IMC conditions, as it may leave the pilot with a daunting task of hand flying the aircraft, especially if they are not comfortable or qualified to do so.
What are some of the limitations of the PC12 autopilot as discussed in the NTSB report from a 2017 accident?
-The limitations include the autopilot disconnecting during spatial disorientation, moderate turbulence, and night IMC conditions, which can lead to the pilot losing control of the aircraft.
How does the autopilot engage and disengage on the PC12 aircraft?
-The autopilot on the PC12 is engaged by pushing the autopilot button on the flight guidance control panel, and it can be disengaged by pressing the same button or the big red autopilot disconnect button located on the left side of the yoke.
What is the purpose of the trim trigger on the control wheel of the PC12?
-The trim trigger on the control wheel allows the pilot to temporarily disconnect the autopilot and manually retrim the aircraft without completely disconnecting the autopilot, which is useful for adjusting the aircraft's trim during flight.
What are the autopilot monitor limits that can cause the autopilot to disconnect on the PC12?
-The autopilot will disconnect if the roll rate is greater than 10° per second, pitch rates are more than 5 degrees per second, or if accelerations exceed a plus 1.6g or fall below a negative 0.3g envelope.
How does the PC12 handle stall conditions in relation to the autopilot?
-If the aircraft enters a stall condition, even if temporarily due to turbulence, the autopilot will disconnect. This can happen if the angle of attack exceeds the critical angle as indicated by two independent angle of attack sensors located on each wing.
What actions should a pilot take immediately after an autopilot disconnect in the PC12?
-The pilot should first focus on flying the aircraft and disregard the warnings momentarily, then turn off the autopilot warnings by pressing the red autopilot disconnect button on the yoke, and once the aircraft is under control, attempt to re-engage the autopilot within its operational limits.
Why is ongoing professional training important for pilots transitioning to the PC12?
-Ongoing professional training is crucial to maintain proficiency in handling the complex automation and systems of the PC12, especially for pilots who are new to the aircraft or transitioning from smaller aircraft.
What is the recommendation for new PC12 pilots regarding training and mentorship?
-New PC12 pilots are recommended to attend formal training programs like those offered by Simcom or Flight Safety and, if they are relatively low-time pilots, to fly with a mentor pilot for 150 to 200 hours to gain experience in various conditions.
Outlines
🛩️ Autopilot Disconnection Issues in PC12 Aircraft
The script discusses the recent loss of the Nand's Gospel family in a PC12 accident, which occurred due to autopilot disconnection during convective turbulence. It highlights a concerning trend in the PC12 community where autopilot disconnection has led to loss of control in Instrument Meteorological Conditions (IMC). The script reviews autopilot limitations, emphasizing the challenges faced by single-pilot operations in IMC, especially if not proficient in hand-flying. It references an NTSB report from a 2017 accident, underscoring the autopilot's limitations and the critical need for pilots to understand and manage these systems effectively. The autopilot's operation, including how to engage and disengage it, is explained, along with the consequences of exceeding certain flight parameters that lead to disconnection, such as roll rate, pitch rate, and G-force limits. The script stresses the importance of pilot training to handle such situations and the potential for sudden autopilot disconnection during turbulence.
🚨 The Consequences of Autopilot Disconnection in Turbulence
This paragraph delves into the specific circumstances under which the PC12's autopilot can disconnect, particularly during turbulence, and the subsequent challenges for pilots. It explains how exceeding the aircraft's angle of attack can lead to a stall, causing the autopilot to disengage. The script describes the cockpit warnings that occur when the autopilot disconnects, including visual and auditory alerts, and the importance of promptly addressing these warnings to maintain control of the aircraft. The narrative underscores the necessity for pilots to be trained to manage the aircraft manually in the event of autopilot disconnection, especially in turbulent conditions. It also touches on the importance of ongoing professional training for pilots transitioning to complex aircraft like the PC12 and the need for mentorship for less experienced pilots.
📚 The Importance of Pilot Training and Mentorship
The final paragraph emphasizes the critical role of formal training and mentorship for pilots flying the PC12, especially for those with lower flight hours. It mentions the requirement set by Clemens Aviation Insurance for PC12 owners to undergo formal training at recognized institutions like Simcom or Flight Safety. The script also suggests that inexperienced pilots should fly with a mentor for a significant number of hours to gain familiarity with the aircraft's advanced systems and automation. The paragraph concludes with a call to action for pilots to invest in their training and proficiency, ensuring they can safely handle complex aircraft like the PC12, and a note of thanks to the channel's supporters.
Mindmap
Keywords
💡PC12
💡Autopilot
💡Loss of Control
💡IMC (Instrument Meteorological Conditions)
💡Spatial Disorientation
💡Autopilot Disconnect
💡Angle of Attack
💡Stall
💡Training and Proficiency
💡Aviate, Navigate, Communicate
Highlights
Recent loss of the Nand's Gospel family in a PC12 accident due to autopilot disconnection in turbulence.
History of PC12 accidents in 2019 showed six incidents of loss of control in IMC conditions after autopilot disconnection.
Review of autopilot limitations on PC12, especially in single pilot operations.
Autopilot disconnection can occur due to various reasons including exceeding certain flight parameters.
NTSB report from a 2017 PC12 accident highlighting autopilot limitations.
Probable cause of the 2017 accident was loss of airplane control due to spatial disorientation after autopilot disconnection.
Description of how to control and manage the autopilot on a PC12.
Autopilot disconnects if aircraft exceeds certain roll, pitch rates, or G-force limits.
Autopilot will also disconnect if a stall is detected, even briefly.
Procedures for climbing in a PC12 with autopilot, including setting altitude and speed.
Risks of autopilot disconnection in turbulence and the importance of being prepared to manually control the aircraft.
Cockpit warnings and alarms that occur when the autopilot disconnects.
The necessity to fly the aircraft first and then address the autopilot warnings.
Re-engaging the autopilot after addressing the initial disconnection and controlling the aircraft.
Importance of professional training for pilots transitioning to complex aircraft like the PC12.
Recommendation for low-time pilots to fly with a mentor before managing the PC12's automation.
Suggestion to have a second pilot or professional to fly complex aircraft like the PC12.
Acknowledgment of Patreon supporters for enabling the creation of such content.
Transcripts
the recent loss of the nand's Gospel
family ban in a pc12 accident following
a autopilot disconnect while entering an
area of convective turbulence follows a
trend in the PC2 community that deserves
a second look let's check it out if we
take a brief look back at the history of
the pc12 this article comes from the
used aircraft guide published in 2019
back in 2019 there were already six
different pc12 accidents that were were
the result of loss of control of the
aircraft in IMC conditions most of these
cases were preceded by the autopilot
disconnecting and then the pilot losing
control of the aircraft in instrument
meteorological conditions so I think
it's important to review the limitations
of the autopilot on board the pc12 very
similar to many other aircraft because
when the autopilot disc connects and if
you're a single pilot operation
in IMC conditions you could be faced
with a very daunting
task especially if you are not
particularly comfortable current or
qualified to hand fly the aircraft in
instrument meteorological conditions so
why are these autopilots disconnecting
and why are some single pilot Crews
having an especially hard time managing
the aircraft and re-engaging the
automation once the autopilot has
suddenly and surprisingly kicked off on
you and if we go back and look at at
this NTSB report from an accident back
in 2017 regarding a pc12 in a part 135
Air Taxi commuter accident situation
they give a good breakdown of some of
the limitations of the pc12 autopilot
now some of these limitations may change
based on exactly which Mak model of
patus pc12 you're flying the ntsp
probable cause from this 2017 accident
was the Pilot's loss of airplane control
due to spatial disorientation during the
initial climb after takeoff in night
instrument meteorological conditions and
moderate turbulence and this was
preceded by an autopilot
disconnect on the PC2 you control the
autopilot the mode of the autopilot
using this panel up
here here on your flat screen display
the results of what you put into the
autopilot are displayed up here in the
upper portion of your flat screen
display telling you exactly what mode
the autopilot is in and here on the Yoke
are a series of buttons that help you
manage the autopilot and especially
important is the big red autopilot
disconnect button located right here
next to the big red autopilot disconnect
button is a trim
switch you engage the autopilot on the
PC2 by pushing the autopilot button
located right here on the flight
guidance control panel as long as the
aircraft is within limits for the
autopilot the autopilot will
engage you can disengage the autopilot
by pushing this autopilot button again
or by pressing the big red autopilot
disconnect button located on the left
side of the
Yol the pc12 also has a trim trigger on
the control wheel where if you want to
temporarily disconnect the autopilot and
manually retrim the aircraft that'll
allow you to do that without completely
disconnecting the autopilot and Y damper
so if you pull in the trim trigger the Y
the autopilot is temporarily off the Y
damper remains engaged you can trim the
aircraft and then release the trigger
and the autopilot is back
on this is important because on most any
airplane if you attempt to trim manually
trim the aircraft with the autopilot
engaged the autopilot will
disconnect the autopilot will also
disconnect if the trim interrupt switch
is pushed that's the button you push in
the event of a runaway trim to stop the
trim from moving that'll disconnect the
autopilot or if the alternate stabilizer
TM trim switch is set to up or down
that'll kick off the autopilot a loss of
power to the autopilot computer or the
trim adapter occurs that'll kick it off
the monitors within the autopilot
computer detect a failure or the
following autopilot monitor limits are
exceeded but there's one additional
thing that'll kick off the autopilot
guaranteed every time that's not
mentioned in this list and that is if
you stall the aircraft even briefly so
these are the limits of the autopilot if
you have a roll rate greater than 10°
per second the autopilot will not will
disconnect and it will not reconnect
pitch rates more than 5 Dees per second
or accelerations outside of a plus 1.6g
or I think that's supposed to be a
negative
.3g envelope so if you get this is where
the autopilot kicks off in turbulence if
you get into turbulence and you exceed
these G limits which is quite easy to do
in turbulence
the autopilot will kick off now if you
get yourself disoriented and and start
maneuvering the aircraft a lot outside
of these limits the autopilot will not
re-engage the pc12 has two angle of
attack veins located one on each Wing
unlike Boeing
737
cut the PC2 has two independent angle of
attack veins located one on each Wing
when both of these angle of attack
indicators agree that you have exceeded
the critical angle of attack of the
aircraft it will sense the stall and
tell you that the aircraft is
stalling if the aircraft enters
installed condition even if
temporarily for example in turbulent air
conditions the autopilot will
disconnect normally if you want to climb
up to altitude in the pc12 you set your
altitude and the altitude window here
and then you engage the speed mode of
the autopilot which is similar to flight
level change for you boing guys and then
the aircraft will hold that speed and
you select a speed that's normally 20 or
more knots above your best rate of climb
speed to give you a good buffer from a
stall margin while you're climbing and
you set your power and it'll give you
whatever rate of climb you can get at
that power setting to hold that speed
and give you speed protection but in
turbulent air conditions you can get a
gust of wind or a brief wind shear that
even at that speed you can briefly
exceed the critical angle of attack of
the wing especially if you're
heavyweight because you're heavyweight
climbing out you're already fairly close
to the critical angle of attack you hit
a good gust of wind and you can
temporarily briefly stall the aircraft
and the autopilot will kick off and it
can be a cacophony of events in the
cockpit you can hear stall stall stall
and then autopilot disconnect and then
the associated autopilot disconnect
warnings now these stalled this
condition where it just hits you
suddenly and then the aircraft recovers
very quickly is not enough of a stall to
engage the other systems on board the
pc12 which include a stick Shaker and a
Stak stick Pusher but it will disconnect
the autopilot and if you're single pilot
IFR and not really up on your instrument
meter meteorological conditions flying
skills this can be a very surprising and
disconcerting
situation because when the autopilot
disconnects these are some of the
different warnings you're going to get
in the cockpit the cause system they
mention here caws is the central
advisory warning system so on the mode
control the autopilot caption flashes
four times and turns off on the cause
display unit the Amber autopilot dis
disengage message illuminates for 3
seconds and uh on the E AI the red
autopilot caption flashes five times
then turns off and the autopilot
disconnect warning tone is annunciated
in this is annunciated in the
loudspeakers and the headsets and the
cause gong warning tone is also
enunciated so suddenly the cockpit is
kind of lit up like a Christmas tree and
all sorts of warnings are going off and
the only way to turn All These Warnings
off is you got to reach up and hit the
auto pilot disconnect button to turn all
this stuff off so aviate navigate
communicate the first thing you got to
do is jump on the gauges and fly the
airplane and disregard all these
warnings for a second because you know
what it is you should know what it is
the autopilot disconnected but it
surprised you in this particular
situation so the next thing you're going
to need to know through your training is
to turn all that racket off by hitting
the red autopilot disconnect button on
the
Yoke now once you get the aircraft under
control with a known pitch and power
setting and the autopilot warnings all
turned off now you can go about
reselecting re-engaging the autopilot as
long as you're within limits of the
autopilot
limitations and continue on with the
flight but if you begin to struggle with
wondering what is going on with your
automation if all of these warnings are
throwing you for a loop you can quickly
and easily begin to lose control of the
aircraft if you fail to fly the aircraft
first and if you're a Private Pilot or a
commercial pilot that is transitioning
to the for the first time to something
as big and complicated as the pc12 this
is why you need to go to school a
professional training program maintain a
professional training program every
every year to remain current and
proficient in this complicated level of
an aircraft talking to my friend Jerry
Clemens of Clemens Aviation insurance he
requires that if you're going to own one
of these pc1 12s that you're going to
have to attend formal training in either
simcom or flight safety and if you're a
relatively low time pilot you're going
to need to fly with a mentor pilot for
150 to 200 hours an experienced rated
pilot in the PC 12 in all sorts of
conditions before you get very familiar
with the flat panel display and the
management of the Automation in this
aircraft and as my friend Hoover said in
his 17-minute video on the neand plane
crash if you can afford something like a
PC 12 at least you can afford a second
pilot to fly with you or a professional
pilot to fly the aircraft for you thank
you so much for your support of this
channel especially the folks over on
patreon that make this content possible
see you here
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