julesmusician
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747 Gliding On No Engines - New Incident

Sat Jan 14, 2006 7:49 pm

Following the incident over London where a 747 was running with very little engine power there have been recommendations that all pilots should be aware of their no power gliding profile of their aircraft - is this every done in simulators or if this did happen is it always down to a pilot's skill?

Incident is here:

http://www.aaib.gov.uk/cms_resources/N481EV%201-06.pdf

J
African Civil Aviation Commission president "You don't want to fly out as a passenger and come back as cargo."
 
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HAWK21M
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RE: 747 Gliding On No Engines - New Incident

Sat Jan 14, 2006 8:46 pm

The commander carried out the descent using the autopilot in the vertical speed mode during which he became aware that the thrust levers were positioned in the “number six position”

What are the Thrust lever positions on a B747.

The crew discussed the anomaly of the forward thrust lever position and low engine power indications and recorded the engine EPRs as: ‘#1 eng 0.704, #2eng 1.124, #3eng 1.206 and #4eng 1.149’

Can EPR read less than 1.What stage are the EPR probes located on a B747

regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
ReidYYZ
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RE: 747 Gliding On No Engines - New Incident

Sat Jan 14, 2006 9:05 pm

Quoting HAWK21M (Reply 1):
Can EPR read less than 1

Yes, at idle, on descent when the air is entering faster than the engine can push it out the ass end.

Quoting HAWK21M (Reply 1):
What stage are the EPR probes located on a B747

Depends which model engines.
 
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HAWK21M
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RE: 747 Gliding On No Engines - New Incident

Sat Jan 14, 2006 10:17 pm

Quoting ReidYYZ (Reply 2):
Yes, at idle, on descent when the air is entering faster than the engine can push it out the ass end.

Wouldn't that be momentary.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
fr8mech
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RE: 747 Gliding On No Engines - New Incident

Sat Jan 14, 2006 10:48 pm

The EPR will less than 1.00 on descent.

The PT2 probe is located on the outboard side of the pylon. Left side for #1 & #2, right side for #3 & #4.

I've worked on the classics quite a bit, I believe I even worked N481EV, back in the day, and I've never heard of the '#6 throttle position'. He may have been referring to the index markings on the pedestal which are used by maintenance to mark throttle positions. 6 would have the throttle standing straight up, but nowhere near their max travel of about 11 or 12 (as I recall).

Interesting, according to the FDR graphic, the engines were stuck around the 1.15 - 1.21 range. This the 'bleed-shift' range (on the ground). As I recall, a JT9-7(x) that won't make power, but still has an increasing EGT, has not had 'bleed-shift'.

Bleed-shift is controlled on the engine independently of the other engines, except that one of th bleed controllers looks at air/ground logic. I just don;t remeber enough about chapter 75 on the JT9 to work it through my head any further.
When seconds count...the police are minutes away.
 
PhilSquares
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RE: 747 Gliding On No Engines - New Incident

Sun Jan 15, 2006 12:46 am

The number 6 position is just the thrust lever markings on the throttle quadrant. They're used for rigging.

As a technique, I avoid using V/S because you can get slow very easy. In the older JT-9 engines, if you got slow it really took a good airflow through the fan to make sure the engine would accelerate. As Fr8Mech pointed out, there is a bleed shift issue and the older engines really suffer from those problems.
Fly fast, live slow
 
KJFK31L
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RE: 747 Gliding On No Engines - New Incident

Sun Jan 15, 2006 2:23 am

The report cited that the aircraft engines have a bleed air issue when the 747 is operating "light". It also indicates that the way to rectify such an issue is to power up the engine (to position 6). After 10 seconds the valve will reset itself and normal flight can be resumed.

Is this a common problem for 747-200 cargo aircraft operating with small cargo loads?

Matt
If it's not Boeing, I'm not going.
 
PhilSquares
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RE: 747 Gliding On No Engines - New Incident

Sun Jan 15, 2006 5:14 am

Quoting KJFK31L (Reply 6):
Is this a common problem for 747-200 cargo aircraft operating with small cargo loads?

It's a common problem for all older 747-200s with PW powerplants. Another way to bypass the problem is to turn on the engine anti-ice.
Fly fast, live slow
 
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HAWK21M
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RE: 747 Gliding On No Engines - New Incident

Sun Jan 15, 2006 10:55 pm

Quoting PhilSquares (Reply 5):
The number 6 position is just the thrust lever markings on the throttle quadrant. They're used for rigging.

Any Pics on the Throttle Quadrant showing the Marks.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
fr8mech
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RE: 747 Gliding On No Engines - New Incident

Mon Jan 16, 2006 12:57 am

Quoting HAWK21M (Reply 8):
Any Pics on the Throttle Quadrant showing the Marks.

Mel,

It's just a scale on the throttle quandrant. There is a prominent mark at 3.7, which is the part-power rig point. This is the point where the cable system, from the pylon, down to the JFC is rigged.


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HAWK21M
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RE: 747 Gliding On No Engines - New Incident

Mon Jan 16, 2006 2:21 am

Thanks for the Pic.  Smile
regds
MEL
I may not win often, but I damn well never lose!!! ;)

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