Don't Forget To Chock Those Wheels

[Robbie Stuart]

From www.landings.com

Landings: News: Aviation News by Pacific Flyer


unchocked wheels

A brake-metering-valve failure caused a B-1B Lancer to collide with two aircraft rescue firefighting vehicles March 7 in Guam causing $5.8 million in damage, plus no one bothered to put chocks on the wheels.

That s according to an Air Combat Command accident investigation board.

The board determined the aircraft began to roll forward after engine shutdown at Andersen Air Force Base, Guam. Malfunction of the right-hand brake-metering valve caused depletion of the associated brake-system accumulators, rendering the aircraft s brake systems inoperative when the engines shut down.

There were no injuries but lots of red faces. The B-1B is assigned to the 28th Bomb Wing at Ellsworth AFB, S.D.

Contributing factors to the mishap included a slight taxiway declination, failure of the aircraft to be chocked in a timely manner and the inability of the firefighting vehicles to successfully clear the path of the rolling B-1B. The in-flight loss of the No. 3 hydraulic system due to improper swage operations (whatever that may be) and post-task inspection caused the initial in-flight emergency that necessitated landing at Andersen AFB, so it was also cited as a substantially contributing factor.

In other words, if they hadn t had an emergency, they wouldn t have had to land and because they had to land and someone didn t put chocks on the wheels, it rolled into two firefighting trucks. You know some Airman is going to get the blame for this.

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I hate it when that happens. Glad no body got hurt. Ive seen people do some crazy stuff trying to get an aircraft stopped once they start rolling.
Robbie

[skymstr02]

The in-flight loss of the No. 3 hydraulic system due to improper swage operations (whatever that may be)

The hydraulic lines were not fabricated correctly.

[Bill Walker]

To be specific: swaging is the process of deforming a portion of a hydraulic fitting to form a tight seal on the end of a hydraulic hose or rigid tube. If you don't do this correctly, and don't inspect it to be sure it was done correctly, the fitting can leak or even blow right off the line. This can happen the first time you pressurize the line, or (worst case) some random time after the swaging is performed.

Given the tight fit inside a modern aircraft like the B-1, replacement of hydraulic lines can often involve swaging in place, after a replaced or repaired line is threaded through the rest of the aircraft systems and structure. Don't know about this one, but I have seen several failures like this where the swaging was done in the dark, at the end of a long shift, by a tech standing on his head to reach the thing.

[RickH]

5.8 million cause he blew a hose !

[chaser]

5.8 million cause he blew a hose !

because the airplane wasn't chocked.....basic procedure not being followed.

[Ken]

Although verifying chocks after shutdown is a normal procedure, at the airline and in the USAF, when an airplane is ground-egressed after an emergency, chocks are not hard-and-fast procedure. In the C-130, we typically ask our Loadmaster to chock the nose gear, time/situation/safety permitting .... but the first step of the egress procedure is "parking brake-set" and it stays set while the crew runs away. The only caveat that comes to mind is for hot brakes where the pilot may choose to set brakes on only one set of main gear (by using one pedal).

Maybe crash/fire has a procedure to supply chocks? In any event, I can see how this would happen and maybe the procedures should be re-thought. That said, the books can't cover every conceivable emergency; there will always be "new" emergencies to contend with - that's where dollars invested in a crew's systems knowledge can possibly save the day. The only way to achieve 100% safety is to park the fleet. Then again, the number of paper cuts would rise ...

[gary1954]

"Anything that can go wrong will go wrong at the worst possible moment"
Murphy's Law

[RSpivey]

http://www.af.mil/shared/media/photodb/photos/080325-F-3817W-202.jpg

Always chock em

[mustangdriver]

An accident is always a chain of events.

[kenlyco]

[TonyM]

kenlyco,

Do you know the circumstances on that one?

Don't look like the chocks would have helped out there.

TonyM

[kenlyco]

A freind of mine that works for Timco sent me those.I think they were doing a full runup and they were looking at the gauges and not what was going on outside,don't quote me on that though. Ther is probly something on the Net.

[krlang]

An accident is always a chain of events.

He could have broke that chain if he didnt choke when chocking?

[dhfan]

The Airbus was brand-new and doing full-power run-ups. It was due for delivery very soon, the following day according to some reports. Exactly what happened doesn't appear to have been released but it seems they had all four engines at max power. The brakes had no chance...

[warbird1]

The Airbus was brand-new and doing full-power run-ups. It was due for delivery very soon, the following day according to some reports. Exactly what happened doesn't appear to have been released but it seems they had all four engines at max power. The brakes had no chance...

Here is what happened, as relayed to me via e-mail:


"The brand spanking new Airbus 340-600, one of the largest passenger airplane
ever built, sat in its hangar inToulouse, France without a single hour of
airtime. Enter the Arab flight crew of Abu Dhabi Aircraft Technologies
(ADAT) to conduct pre-delivery tests on the ground, such as engine
runups, prior to delivery to Etihad Airways in Abu Dhabi.

The ADAT crew taxied the A340-600 to the run-up area. Then they took all
four engines to takeoff power with a virtually empty aircraft. Not
having read the run-up manuals, they had no clue just how light an empty
A340-600 really is.

The takeoff warning horn was blaring away in the cockpit because they
had all 4 engines at full power. The aircraft computers thought they were
trying to takeoff but it had not been configured properly (flaps/slats, etc.)

Then one of the ADAT crew decided to pull the circuit breaker on the
Ground Proximity Sensor to silence the alarm. This fools the aircraft into
thinking it is in the air. The computers automatically released all the
brakes and set the aircraft rocketing forward. The ADAT crew had no idea
that this is a safety feature so that pilots can't land with the brakes
on.
Not one member of the seven-man Arab crew was smart enough to throttle
back the engines from their max power setting, so the $200 million brand-new
aircraft crashed into a blast barrier, totaling it. The extent of
injuries to the crew is unknown, for there has been a news blackout in the major
media in France and elsewhere. Coverage of the story was deemed
insulting to Moslem Arabs. Finally, the photos are starting to leak out. Airbus
$200 million aircraft meets retaining wall and the wall wins...."