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B752 Fqis Process Reliability  
User currently offlineHAWK21M From India, joined Jan 2001, 31679 posts, RR: 56
Posted (8 years 3 months 2 weeks 4 days 5 hours ago) and read 1835 times:

How Reliable is the FQIS Processor on the B752.
Any Memories of needing to Override the Fuelling valves.
regds
MEL

[Edited 2006-05-17 19:38:51]


Think of the brighter side!
15 replies: All unread, jump to last
 
User currently offlineAtlamt From United States of America, joined Sep 2001, 240 posts, RR: 3
Reply 1, posted (8 years 3 months 2 weeks 4 days 4 hours ago) and read 1821 times:

The fueling system itself is pretty reliable. The indication system is another story. We get fuel qty bite messages on a regular basis. Most of the time when you bite the box it verifies no faults are present. Reset the box and go flying.

We have gone to a new style of processor and it has helped but didn't completely fix the problem.



Fwd to MCO and Placard
User currently offlineTristarsteve From Sweden, joined Nov 2005, 4001 posts, RR: 34
Reply 2, posted (8 years 3 months 2 weeks 4 days 4 hours ago) and read 1819 times:

FGIS Bite maint messages are quite common, but the system itself is very reliable. One feature of the B757 is that when you dial up 6000kg on the preselect, it stops with 6000kg in the tank. I think it is the only aircraft I work on which is so precis. Note that the older B757s (pre about 1998) refuel very slowly. It can take 20 mins to get to full wings ( about 13200kg), but about the same time to get to full tanks!.
I can only remember once doing a manual override of a refuel valve in 20 years. Even with a gauge failure the valves still open using the refuel panel switches.
One tip, if no fuel goes in it can be the overfill system at fault. Try pressing the overfill reset. If the fuel flows, then stops again when you let go then you can keep the button pushed in with a Shell water detector metal container. Get one from the refueller and bend it slightly and you cab wedge the button in. Saves your fingers. This happens about 4 times a year.


User currently offlineFr8mech From United States of America, joined Sep 2005, 5400 posts, RR: 14
Reply 3, posted (8 years 3 months 2 weeks 4 days 4 hours ago) and read 1814 times:

I've opened plenty of fuel valves using the manual override feature. Simple and quick. Try to remember, it goes much easier with pressure off the manifold.

Fuel Qty Bite messages are rather common, Fuel Qty Channel much less so.



When seconds count...the police are minutes away.
User currently offlineHAWK21M From India, joined Jan 2001, 31679 posts, RR: 56
Reply 4, posted (8 years 3 months 2 weeks 3 days 11 hours ago) and read 1774 times:

Quoting Tristarsteve (Reply 2):
One tip, if no fuel goes in it can be the overfill system at fault. Try pressing the overfill reset. If the fuel flows, then stops again when you let go then you can keep the button pushed in with a Shell water detector metal container. Get one from the refueller and bend it slightly and you cab wedge the button in. Saves your fingers. This happens about 4 times a year.

What was the Snag Rectification.
Replaced Overfill Sensor.
regds
MEL



Think of the brighter side!
User currently offlineTristarSteve From Sweden, joined Nov 2005, 4001 posts, RR: 34
Reply 5, posted (8 years 3 months 2 weeks 3 days 6 hours ago) and read 1755 times:

Quoting HAWK21M (Reply 4):
What was the Snag Rectification.
Replaced Overfill Sensor.

Usually the FQIS computor at fault.


User currently offlineHAWK21M From India, joined Jan 2001, 31679 posts, RR: 56
Reply 6, posted (8 years 3 months 2 weeks 2 days 14 hours ago) and read 1729 times:

Quoting TristarSteve (Reply 5):
Usually the FQIS computor at fault.

Is the FQIS Processor snag prone.
regds
MEL



Think of the brighter side!
User currently offlineDl757md From United States of America, joined May 2004, 1562 posts, RR: 16
Reply 7, posted (8 years 3 months 2 weeks 2 days 12 hours ago) and read 1723 times:

Quoting HAWK21M (Reply 4):
What was the Snag Rectification.
Replaced Overfill Sensor.

The first thing you want to do is see if you get any fuel out of the surge tank sump drains. I've gotten as much as a gallon out of them and it fixes the problem. In my experience this has been the cause about 30% of the time.

DL757Md



757 Most beautiful airliner in the sky!
User currently offlineBuzz From United States of America, joined Nov 1999, 697 posts, RR: 21
Reply 8, posted (8 years 3 months 2 weeks 2 days 11 hours ago) and read 1718 times:

Hi again Hawk21M, Buzz here. I've seen a lot of single channel messages for densitometer problems. But the 757 fuel qty system just keeps chugging along.

I haven't had the problems the other guys have run into, once in a while hear of it happening.
g'nite


User currently offlineFr8Mech From United States of America, joined Sep 2005, 5400 posts, RR: 14
Reply 9, posted (8 years 3 months 2 weeks 2 days 11 hours ago) and read 1717 times:

Quoting HAWK21M (Reply 6):
Is the FQIS Processor snag prone.

No, people just like to shoot the messenger. Drain the fuel out of the tank and move along. Occasionally a bad sensor, I also see to recall a relay we've replaced before.

A chronic problem was the D1, D2, D3 messages on the FQIS processor. Basically telling you the densitometer was bad. Used to be radioactive, don't think it is anymore. Problem seems to have gone away also.



When seconds count...the police are minutes away.
User currently offlineA/c train From United Kingdom, joined Jun 2001, 501 posts, RR: 4
Reply 10, posted (8 years 3 months 2 weeks 1 day 4 hours ago) and read 1682 times:

lost power completely to the refuel panel once and had to open refuel valves manually

User currently offlineFr8Mech From United States of America, joined Sep 2005, 5400 posts, RR: 14
Reply 11, posted (8 years 3 months 2 weeks 1 day 3 hours ago) and read 1678 times:

Here's a quick tidbit of information:

When the fuel panel door is opened, some people will slam it open in order to go passed the detents. This slamming may cause damamge to the bulbs installed on the door. If the bulb filiment shorts, not breaks and opens, but shorts to the base, it may cause the FQIS processor to fail. Seen it, lived it, learned a big lesson from it.



When seconds count...the police are minutes away.
User currently offlineHAWK21M From India, joined Jan 2001, 31679 posts, RR: 56
Reply 12, posted (8 years 3 months 2 weeks 13 hours ago) and read 1661 times:

Quoting Fr8Mech (Reply 9):
Basically telling you the densitometer was bad. Used to be radioactive, don't think it is anymore. Problem seems to have gone away also

There are two Manufacturers of the Densitometers used on the B752.Of which one is considered Radioactive.

Quoting A/c train (Reply 10):
lost power completely to the refuel panel once and had to open refuel valves manually

What was the rectification finally.

regds
MEL



Think of the brighter side!
User currently offlineA/c train From United Kingdom, joined Jun 2001, 501 posts, RR: 4
Reply 13, posted (8 years 3 months 2 weeks 11 hours ago) and read 1660 times:

Hi HAWK, well the night shift found a damaged wire going to the refuel panel, that loom that runs stupidly close to the slat drive shafts, carried out the repair and the refuel panel functioned satis, does anyone else think that wiring loom behined the refuel panel runs a little close? has it been SB'd out of the problem?

User currently offlineFr8Mech From United States of America, joined Sep 2005, 5400 posts, RR: 14
Reply 14, posted (8 years 3 months 2 weeks 10 hours ago) and read 1654 times:

Quoting HAWK21M (Reply 12):
Of which one is considered Radioactive

I don't think either are emmiters anymore.



When seconds count...the police are minutes away.
User currently offlineHAWK21M From India, joined Jan 2001, 31679 posts, RR: 56
Reply 15, posted (8 years 3 months 1 week 6 days 18 hours ago) and read 1630 times:

Quoting Fr8Mech (Reply 14):
I don't think either are emmiters anymore.

What caused the change.
regds
MEL



Think of the brighter side!
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