Leaving all engines running at the gate

snowy squirrel wrote:

John wrote:

Recently at SJU I saw an IB A340-600 arrive from Madrid that left all
four engines running during the 2 hours that it was at the gate before
continuing to Santo Domingo.

If you could see the engines turning, it means that they were shut off and
just slowly turning due to wind.

It would be very hard for maintenance personel to get near the aircraft with
all 4 engines running. And I suspect extremely hazardous (if not illegal) to
refuel while engines are running.

It is far more likely that what you saw were just engines turning slowly due
to wind.

There are situations where engines on one side are left running in extreme
cold arctic conditions, and all passenger, cargo, fuel is handled from the
other side. This is to ensure that at least one engine is available to
generate sufficient power to restart the second engine.

Nope, those four fans were running at a pretty good clip. No wind
involved there. Besides, with the size of those things, it would take
a hurricane to keep them turning for two hours.

"John" wrote in message


Besides, with the size of those things, it would take
a hurricane to keep them turning for two hours.

Have you ever turned a turbine engine?

--
John T
http://tknowlogy.com/TknoFlyer
http://www.pocketgear.com/products_s...veloperid=4415
____________________

"John T" wrote in message ws.com...
"John" wrote in message


Besides, with the size of those things, it would take
a hurricane to keep them turning for two hours.

Have you ever turned a turbine engine?

Yep, the wind easily turns the bypass fans. When I had a friend flying
for UPS, we climbed up into the intake of a 767. You could easily
grab the blades and spin them around at a pretty good clip. We scared
the hell out of the load master who saw the thing start to turn with vigor
and thought the engines were being start on him.

"John" wrote in message

Nope, those four fans were running at a pretty good clip. No wind
involved there. Besides, with the size of those things, it would take
a hurricane to keep them turning for two hours.

Rotor sections are *extremely* finely balanced, else they would vibrate the
engine right off the wing at operational speeds. What this means is that
the blade wheels will turn freely with very little force applied. A light
breeze will suffice, no hurricane required. In my experience, more often
than not you'll see these things turning (at least with large fan engines)
if there's any breeze exposure at all.


Regards,

John Gaquin
B727, B747

John wrote:



Nope, those four fans were running at a pretty good clip. No wind
involved there. Besides, with the size of those things, it would take
a hurricane to keep them turning for two hours.

It takes very little wind to turn the blades.

If you could see the blades turning then the engines coudn't be running.

Karl

"John" wrote in message
...
snowy squirrel wrote:

John wrote:

Recently at SJU I saw an IB A340-600 arrive from Madrid that left all
four engines running during the 2 hours that it was at the gate before
continuing to Santo Domingo.

If you could see the engines turning, it means that they were shut off
and
just slowly turning due to wind.

It would be very hard for maintenance personel to get near the aircraft
with
all 4 engines running. And I suspect extremely hazardous (if not illegal)
to
refuel while engines are running.

It is far more likely that what you saw were just engines turning slowly
due
to wind.

There are situations where engines on one side are left running in
extreme
cold arctic conditions, and all passenger, cargo, fuel is handled from
the
other side. This is to ensure that at least one engine is available to
generate sufficient power to restart the second engine.

Nope, those four fans were running at a pretty good clip. No wind
involved there. Besides, with the size of those things, it would take
a hurricane to keep them turning for two hours.


Was the rotating beacon on? If not the engines were most likely
windmilling.

It would be to dangerous to leave one engine running at the gate. Let
alone four. Too many people and equipment in the area. Turbo fan engines
have a tendency of sucking anything that gets to close. Paper or a plastic
bag or plastic wrap that is use to wrap cargo. That's including people
too. There is just to much crape around the gate just waiting to get suck
in. It doesn't take much to damage one of those fan blades. At 20-30,000
dollars per fan blade (For a RB-211. American Airlines 757 ). I don't
think they will leave them running unless they want to be changing fan
blades more often on the A340.


aptim A&P

"John" wrote in message Nope, those four fans were running at a pretty
good clip. No wind
involved there. Besides, with the size of those things, it would take
a hurricane to keep them turning for two hours.

Iberia usually parks at gate 27 where the prevailing wind blows up the
tailpipes. A 4 knot wind is sufficient for spinning a fan disk. If you could
see the blades, the engines weren't running.

D.