United B777 #830 SYD Center Hydraulic System Failure
Summary
TLDRThe transcript discusses a hydraulic system failure in a Boeing 777, highlighting the aircraft's design resilience and redundancy. Despite the loss of the center hydraulic system, the plane was able to operate safely, albeit requiring a labor-intensive emergency procedure. The incident involved a United Airlines flight from Sydney, which had to return due to a leak in the right main landing gear. The video also touches on a wheel failure event in a different flight and a turbulence incident involving a LANTOM 787. The importance of following checklists and training in handling such emergencies is emphasized.
Takeaways
- ๐ซ The loss of the center hydraulic system in a Boeing 777 is significant due to the majority of hydraulically operated components being located on this system.
- ๐ ๏ธ Despite the loss, the aircraft can still operate thanks to its excellent design and built-in redundancy, though it is one of the most labor-intensive emergencies for a flight crew.
- ๐ฅ United Airlines recently faced this issue on a flight departing from Sydney, which had to be handled as an emergency procedure.
- ๐ The normal operation of landing gear and flaps on the Boeing 777 is via the center hydraulic system, which has six wheels on each bogey to distribute the aircraft's weight.
- ๐ง In case of the center system failure, alternate procedures for landing gear extension and flap extension are used, which are much slower and require careful management.
- ๐ก The Boeing 777 is designed with three separate hydraulic systems, each capable of powering all primary flight controls, providing redundancy and safety.
- ๐ฌ๏ธ The center hydraulic system is powered by two large pneumatic pumps and two electric pumps, ensuring a backup in case of failure.
- ๐ The emergency landing procedure involves using a DC-operated motor for landing gear extension and an electrical alternate extension system for flaps.
- ๐๏ธ The aircraft's gear design allows for smooth landings, with the gear tilting up to distribute the weight individually on each wheel, enhancing suspension.
- ๐ Upon landing, the automatic deployment of spoilers is managed by the weight on the wheel switch, but in case of an emergency, they need to be manually deployed by the pilot.
- ๐ The flight crew of United's flight 8:30 out of Sydney demonstrated excellent handling of a complex emergency, showcasing the thorough training and preparedness for such situations.
Q & A
What is the significance of the loss of the center hydraulic system in a Boeing 777?
-The loss of the center hydraulic system is significant because most of the hydraulically operated components are located on this system. However, the aircraft's design and redundancy features allow for continued operation, though it becomes one of the most labor-intensive emergencies for the flight crew.
How did United Airlines handle a recent hydraulic failure on a Boeing 777 departing from Sydney?
-United Airlines managed the hydraulic failure by following emergency procedures. The aircraft, which experienced a center hydraulic system failure, was able to return to Sydney safely without major incidents, thanks to the flight crew's adherence to checklists and training.
What is the role of the center hydraulic system in the operation of a Boeing 777?
-The center hydraulic system is crucial for the normal operation of the aircraft, including the movement of the landing gear and flaps. It also plays a role in the steering system and other functions, providing power to the primary flight controls.
How does the redundancy system in the Boeing 777 hydraulics work?
-The Boeing 777 has three separate hydraulic systems, each capable of powering all primary flight controls. Each system has multiple power sources, including engine-driven hydraulic pumps and electric pumps. Additionally, there's a ram air turbine (RAT) that can provide emergency power in case of multiple system failures.
What are the backup procedures for landing gear and flaps in the event of a center hydraulic system failure?
-In case of a center hydraulic system failure, the alternate landing gear extension uses a DC-operated motor to unlock the gear, allowing it to freefall. The flaps can be extended using an electrical alternate extension system, though it is much slower than the hydraulic system.
How does the loss of the center hydraulic system affect the landing procedure?
-The landing procedure is affected as the landing gear does not tilt for landing, and the gear and flaps are stuck in the position they were in when the system failed. The landing requires manual deployment of spoilers and is done with considerably less flaps, specifically at flaps 20 setting.
What are the implications of a hydraulic system failure on the aircraft's brakes?
-The normal brakes are on the right system, while alternate and reserve brakes are on the center system. There is also an accumulator for a fourth method of stopping the aircraft. In the event of a hydraulic failure, the flight crew must rely on these backup systems to ensure the aircraft can be stopped safely.
How does the flight crew handle a hydraulic failure during takeoff?
-If a hydraulic failure occurs during takeoff, the flight crew would follow the appropriate checklists to manage the emergency. They would need to decide whether to continue the flight or return to the airport, considering the fuel capacity and the need for an emergency landing.
What safety measures are in place for passengers during such emergencies?
-Passengers are advised to keep their seatbelts fastened at all times, especially during cruise flight, to minimize the risk of injury in case of unexpected events like hydraulic failures or turbulence.
How do maintenance crews typically address hydraulic system failures?
-Maintenance crews address hydraulic system failures by inspecting and replacing hydraulic lines that have reached their life limit or are damaged. They follow strict guidelines and schedules for replacing components like the flexible lines connected to the landing gear.
What is the role of the flight data recorder (FDR) in investigating aviation incidents?
-The flight data recorder is crucial in investigating incidents as it provides detailed information about the aircraft's performance and the conditions leading up to the event. It helps determine the exact sequence of events and any potential system failures or crew actions that may have contributed to the incident.
Outlines
๐ซ Boeing 747 Center System Hydraulic Failure & Emergency Procedures
This paragraph discusses the significance of a center system hydraulic failure in a Boeing 747 aircraft, highlighting the challenges it poses for flight crews due to the labor-intensive nature of the emergency. It mentions a recent incident involving United Airlines departing from Sydney and the importance of the aircraft's redundancy systems. The paragraph also touches on the aviation industry's current state and the importance of staying updated through notifications and subscriptions.
๐บ United Airlines Flight 8:30 Hyd. Failure & Landing Gear Analysis
The focus here is on the specifics of the hydraulic system failure in United Airlines Flight 8:30, including an analysis of the landing gear and the role of hydraulic lines. It delves into the redundancy of the Boeing 747's hydraulic system, detailing the multiple power sources for each system and the backup measures in place, such as the ram air turbine. The paragraph also describes the procedures for handling gear and flap extension in the event of a hydraulic failure.
๐ฌ Emergency Landing & Post-Incident Handling
This section covers the emergency landing procedures for a Boeing 747 with a center system hydraulic failure, including the use of alternate systems for gear and flap extension. It discusses the considerations for go-around scenarios and the unique landing posture of the aircraft. The paragraph concludes with a review of the flight crew's handling of the situation and the successful return of the aircraft to Sydney, emphasizing the thorough training and preparedness of the crew.
Mindmap
Keywords
๐กBoeing 777
๐กHydraulic System
๐กRedundancy
๐กFlight Crew
๐กEmergency Procedures
๐กLanding Gear
๐กSpoilers
๐กBraking System
๐กWake Turbulence
๐กFlight Data Recorder (FDR)
Highlights
Loss of the center hydraulic system in the Boeing 747 is a significant issue due to the majority of hydraulically operated components being located on this system.
Despite the loss, the aircraft can continue to operate thanks to its excellent design and built-in redundancy.
United Airlines recently dealt with this emergency on a flight departing from Sydney.
The channel encourages viewers to subscribe and check notification settings to stay updated on the latest aviation news.
A wheel failure incident on a United 747 out of San Francisco diverted to Los Angeles is discussed, with photographic evidence suggesting a wheel bearing failure.
A Lantau 787 incident that injured 50 people is mentioned, with preliminary information suggesting an intermittent loss of power and possible pilot reaction.
The normal operation of the landing gear on the Boeing 747 relies on the center hydraulic system, with each bogey having six wheels to distribute the aircraft's weight.
In the event of a center hydraulic system failure, alternate methods for landing gear extension and flap deployment are used, which are labor-intensive.
The Boeing 747's hydraulic system has redundancy with three separate systems, each capable of powering all primary flight controls.
The center hydraulic system is powered by two large pneumatic pumps and two electric pumps, providing a series of backups.
In case of a leak, the center system can trap fluid separate from the system, ensuring some level of functionality for the primary flight controls.
United's flight 8:30 from Sydney experienced a hydraulic system failure, with the crew managing the situation and returning to the airport safely.
The alternate landing gear extension on the Boeing 747 uses a DC operated motor, while the flaps have an electrical alternate extension system.
In an emergency, the landing gear is extended by gravity, and the aircraft is prepared for a potential go-around with flaps 20 landing configuration.
The flight crew's handling of the emergency is praised, showcasing the thorough training and preparedness for such situations.
The braking system on the Boeing 747 has redundancy, with normal brakes on the right system and alternate/reserve brakes on the center system.
Even after landing, the aircraft's wheel brakes, auto brakes, and antiskid systems continue to operate normally due to their connection to the right hydraulic system.
The transcript concludes with a call to action for viewers to support the channel, especially through Patreon, to help continue providing valuable aviation content.
Transcripts
loss of the center system hydraulic
system in the Boeing trip 7 is a big
deal because most of the components
hydraulically operated components on the
Boeing trip 7 are located on the center
system but thanks to the excellent
design of the aircraft and the
redundancy built into this aircraft
there's no problem continuing to operate
the aircraft however this represents one
of the most labor
intensive emergencies that a flight crew
can face in the trip 7
and United had to deal with this
recently on a departure out of Sydney
let's check it
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out
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it's been very tough tough keeping up
with everything that's been going on in
the aviation industry lately but one way
you can do that is to hit your subscribe
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subscription may be
lost a quick update to the Lost wheel
story on the United Tri 7 out of San
Francisco that diverted to Los Angeles
it looks like it was a wheel failure
based on these photographs sent in by a
Blanco Lio viewer the brake assembly is
still shown here on the axle and the
retaining nut and the bolts that retain
the axle retaining nut are in place on
the axle and this appears to be the
outer race to the wheel bearing on the
outside of the
wheel here's a closer look at the axle
with the retaining nut in place and the
bolts that retain the axle nut in place
there's the
timkin roller bearing and the outer race
located right there so it looks like the
wheel fail just outside of the outer
race and it rolled right off up and over
the retaining nut and off of the
aircraft this aircraft has since been
fixed and returned to service and fed
right back up to San
Francisco regarding the lantom 787 that
injured 50 people who apparently were
not wearing their seat belts when they
should have been in Cruise flight
remember anytime you're in your seat
keep that seat belt fastened the only
information we have right now on that is
some testimony from some of the
passengers and this particular passenger
said that the pilot came back and he
asked the pilot what happened and this
passenger says that the pilot said that
all of his screens went blank briefly
and then
reappeared so until we get the flight
data recorder will we know the story of
exactly what happened to the lantom 787
on its flight from Auckland to Sydney
intermittent loss of power to the
aircraft which essentially to me sounds
like the two main AC the left and right
main AC circuits if there was an
intermittent loss of that power did the
autopilot kickoff suddenly and if the
autopilot kicked off suddenly did the
flight crew overreact and bump the
aircraft in a nose down condition or was
the aircraft out of trim and the
aircraft resumed its trimmed position
with the autopilot off one other form of
turbulence that you can encounter that
can replicate this is if you fly
perpendicular through the Wake
turbulence of another aircraft that has
just passed you'll be in perfectly
smooth air and then you'll hit a huge
bump depending on how close you were
behind the other aircraft as you cross
perpendicular to his wake turbulence
Wham like a big speed bump and then
you're back in smooth air but this
sounds more powerful than just simply
Crossing somebody's wake turbulence and
there was no other word of turbulence in
the area prior to this incident so until
we get the FDR then we'll get the rest
of the
story the normal way of raising and
lowering the landing gear on the Boeing
trip 7 is via the center hydraulic
system each landing gear bogey has six
wheels on it to help distribute the
massive weight of the boing Tri 7 which
happens to have a Max gross weight of
777 th000 lb and if we swing around to
the back side of the landing
gear we see four lines four hydraulic
lines two brake lines one there and one
there and then two hydraulic lines that
go to this hydraulic actuator right here
because of the six wheels in order to
turn the Boeing trip 7 while T ing on
the ground especially at tight 90ยฐ turns
below 10 knots the rear two wheels of
the bogey pivot like a large truck in
order to prevent scrubbing of the tires
and allow you these tighter turns and
this is facilitated using this pivoting
arm located right here and this
hydraulic actuator located right here
powered by the center hydraulic system
and connected in association with the no
no wheel steering system and the tiller
up in the
cockpit so as captured by PL spotter New
York Aviation United's flight 8:30 on
Monday the 11th of March departing
Sydney he captured this failure of the
hydraulic system there you can just see
the hydraulic fluid missing out of the
right side landing gear right upon
initial
departure there's that fluid leaking out
right about in that same area we were
just talking about in the landing gear
so it's more than likely one of those
flexible lines and it's pretty common if
you're going to lose a hydraulic system
especially a center hydraulic system it
usually occurs when one of these
flexible lines fails that is attached to
the landing gear and this flexxable line
has to undergo a lot of flexing and
motion as the gear is retracted and
extended and these hydraulic lines do
have a life limit on them and they're
they're dated and banded and so you know
when to replace them according to date
but sometimes they fail before they
their time is expired to replace them so
that's a relatively small hydraulic line
in a large hydraulic system maybe some
of you maintainers can tell us exactly
the center system Reservoir quantity
here but it's going to take a while for
this system to leak down to the point
before the pilots even get a warning of
either Center system quantity low or
Center system pressure low it could be
that perhaps somebody on the ground
notified the crew of the aircraft that
they noticed something leaking out of
the right main landing gear of the
aircraft on departure a quick review of
the redundancy of the Boeing Tri 7
hydraulic system you've got three
separate hydraulic
systems any one of these can power all
of the primary flight controls of the
aircraft any one single system as each
of the primary flight controls are
connected to each of the hydraulic
systems each hydraulic system has
several sources of power the left
hydraulic system has the left engine
driven hydraulic pump and an electric
demand pump the right hydraulic system
has the same thing the right engine
driven hydraulic pump and the right
demand pump the center system has two
large pneumatic pumps using bleed air
from the system to power and they are
demand pumps so they come on when
they're needed and it also has two
electric pumps as well to back that up
so a series of four pumps to power the
center system hydraulic system any one
of which can power the the entire system
but when these gear when the gear and
flaps are in motion it does require a
large volume of hydraulic fluid and
there's also the backup of the ram a
turbine the rat which can provide some
Center hydraulic system trapped fluid to
the primary flight controls in the event
of a either a loss of both engines or B
a loss of both main AC electrical
systems or or see a loss of all three
hydraulic systems again this fluid is
trapped in the center hydraulic system
so that in the event of a leak like this
from the landing gear this fluid will be
trapped separate from that system so
here on flight rate r24 looks like the
crew took off about 130 a.m. Zulu and
headed out about 40 minutes or so before
turning back and coming in land again
this is a labor intensive emergency but
it's not a Time constrained emergency so
you've got all the Time in the World to
sort this out especially when you have
enough fuel to fly all the way from
Sydney to San Francisco and you've got a
bunch of checklists to cover once you
get into the loss of Center system
pressure or quantity checklist it's
going to direct you into how are you now
going to lower the landing gear and the
flaps you're going to have to use the
alternate landing gear extension and
checklist and the alternate flap
extension and checklist the alternate
gear extension on the Boeing Tri 7 uses
a DC operated motor I assume off of the
battery or hot battery bus to unlock the
up loocks to the doors and the landing
gear and allow the landing gear to
freefall the flaps have an electrical
alternate extension system which
bypasses the hydraulic system altogether
but is a very slow system to lower the
flaps so you got to allow for a lot of
time to very slow slowly lower the flaps
also you're going to be getting into
your emergency landing checklist you got
to have go around considerations now
that your gear and flaps are kind of
stuck in that position what are you
going to do in the event of a go round
well you're going to be using a flaps 20
Landing you're going to be landing with
considerably less flaps than you
normally would flaps 20 the same thing
you would do for a single engine Landing
again for go round
considerations in a normal Greaser
Landing in the Boeing trip 7 and this is
why I love this airplane so much the
gear is tilted up like this so you can
just roll those bottom two wheels onto
the runway and then the gear will slowly
tilt forward and then each of the six
wheels will contact the the runway
individually not all at once and so it
just makes for buttery smooth Landings
and an excellent suspension in the oo
struts of the Boeing Triple
7 getting that ground effect
and just roll it on like that just like
butter note also the automatic spoilers
deploying as soon as the weight on the
wheel switch senses weight on the wheels
the auto spoilers
deploy now in this picture from New York
Aviation of the emergency return of
United
Airlines the experienced Triple 7 guy
will know right away that's Center
system hydraulic system failure note the
doors are still down in the open
position normally the doors close behind
the landing gear once it's
extended indicating that they had use
alternate gear extension gravity to get
the gear down and also the landing gear
is not tilted for landing the Tilt
system does not work on emergency gear
extension it just gravity drops the gear
down into the position that it was when
it was
retracted and as we watch this unfold
flaps 20 Landing
boom all six wheels on each bogey hit at
once causing a bit of a Lurch and then
the spoilers need to be manually
deployed so the pilot manually deploys
the spoilers after
landing instead of them automatically
popping out right as soon as the weight
on the wheels is sensed boom normally
they would pop out right there he gets
the nose wheel he's got the aircraft
under control okay let's deploy the
spoilers and come out to a roll out to a
complete and uneventful stop the thrust
reverses of course still work because
they're work operating off the
individual hydraulic systems left and
right and the main landing gear doors
have plenty of clearance to clear the
runway in the open condition during this
Landing wheel brakes Auto brakes and
Anis skid are still operating normally
as they are all operated off of the
right hydraulic system
right here regarding the redundancy of
the braking system on the Boeing trip 7
normal brakes are on the right system
alternate brakes and Reserve brakes are
on the center system and then there is a
accumulator for a fourth way to get this
aircraft stopped plus you have these two
isolation valves to help trap that fluid
for alternate and Reserve brakes over 2
hours later after the aircraft landed
looks like there was still some
hydraulic fluid leaking out of this line
and hitting the hot brakes over here but
the ARF took care of that no problem and
all the passengers deplan the aircraft
back at the gate uneventfully so good
job of the flight crew of United's
flight 8:30 out of Sydney back on Monday
doing one of the most labor intensive
emergency procedures that you can handle
in one of these aircraft but this is
exactly what we train for constantly in
the simulators the checklists are there
the training is there good job thank you
so much for your support of this channel
especially the folks over on patreon
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try and keep up as I try to keep up with
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