QF888 Fuel Leak- Final Report

[flyinghorseman]

https://www.atsb.gov.au/publications/investigation_reports/2021/aair/ao-2021-043

[Occy]

The thread title is a little misleading mainly because there was no “fuel leak”.

Executive summary…. A lot of words to say “the crossfeed valve was open when it should’ve been closed.”

[framer]

It shows two things I reckon,
1/ The saying about the old Captain who noticed the engine failure and slid his seat back and started cleaning his glasses still holds water. The time pressure is often ‘perceived’ not real.
2/ Fuel imbalances in the 737 can be confusing. In the classroom they seem straight forward and then when the sim rolls around they are always more challenging than expected. I imagine in real life it is even more so.

[43Inches]

It shows two things I reckon,
1/ The saying about the old Captain who noticed the engine failure and slid his seat back and started cleaning his glasses still holds water. The time pressure is often ‘perceived’ not real.
2/ Fuel imbalances in the 737 can be confusing. In the classroom they seem straight forward and then when the sim rolls around they are always more challenging than expected. I imagine in real life it is even more so.

The Mildura incident for the VA aircraft also involved a fuel imbalance, which was also related to the crossfeed valve being open and the selection of pumps. So more than one recent occurrence where the complication of the checklist and procedures led to a significant imbalance.

[turbantime]

The Mildura incident for the VA aircraft also involved a fuel imbalance, which was also related to the crossfeed valve being open and the selection of pumps. So more than one recent occurrence where the complication of the checklist and procedures led to a significant imbalance.

That’s because the crew received low fuel level alerts. The checklist calls for opening the crossfeed valve once it is determined that no leak exists. The imbalance was the consequence of differences in fuel pump pressure outputs, which incidentally the sim cannot replicate.

[non_state_actor]

The Mildura incident for the VA aircraft also involved a fuel imbalance, which was also related to the crossfeed valve being open and the selection of pumps. So more than one recent occurrence where the complication of the checklist and procedures led to a significant imbalance.

Yeah nice try🙄

This QF incident had multiple screwups of published procedures including a checklist. If they had either followed the fuel transfer from the manual or just did the checklist properly they would have been fine.

[43Inches]

That’s because the crew received low fuel level alerts. The checklist calls for opening the crossfeed valve once it is determined that no leak exists. The imbalance was the consequence of differences in fuel pump pressure outputs, which incidentally the sim cannot replicate.

The fuel imbalance started before the first fuel low light came on. Most likely as the crew had opened the crossfeed valve, possibly in an effort to ensure both engines had fuel if they forgot. This was discussed by the ATSB in the final report, and they had the conclusion the crew was actioning low fuel and balance operation from memory and not using the QRH. That being said they didn't see an issue with it because of the workload at the time, and the fact that Boeing does not consider large imbalances as an issue, just a wear and tear consideration. So as they stated at the end, the open crossfeed led to the No 2 tank having only 18 kg of fuel at shutdown, however with the crossfeed open both engines would have received fuel from the other tank had it run out. So the crossfeed being left open did lead to a large imbalance, but it was safe to do so, but was avoidable had they waited until a low fuel light actually came on.

Yeah nice try🙄

This QF incident had multiple screwups of published procedures including a checklist. If they had either followed the fuel transfer from the manual or just did the checklist properly they would have been fine.

Not sure what the 'nice try' was about. The ATSB had a little swipe at the VA crew but then said they did nothing wrong, there is a whole page on the subject in the final report. I was showing that the ATSB pointed out the crew were actioning this checklist from memory without regard to the QRH, which is what led to the QF crew doing what they did. Any checklist that can result in a shutdown should be run carefully, unless time pressure is an issue, which it was not in QFs case. BTW the A330 evacuation at the terminal is another QF example of crew not actioning a checklist correctly for a failure, then there is at least the QLink Dash 8 brake fire incident as well. CASA probably should be asking QF group for a please explain on this sort of reoccurring non compliance. Do these companies keep the QRH down in the rear galley or somewhere hard to find? It seems not so quick reference if pilots are just memorizing it (poorly) and stuffing up.

[framer]

I would have liked the report to cover the ambient conditions for the departure so that it was obvious whether or not the ice had to be dealt with at all.
The conditions they did include ( fuel temp of -4 and 4.2T ) didn’t necessarily mean that the ice had to be removed. Basic METAR and ATIS info would have let us know exactly where the chain of events/ errors started.

[Transition Layer]

https://cimg7.ibsrv.net/gimg/pprune.org-vbulletin/1170x884/img_5320_d5d67a7b4cf62fd9e78068645b57c2d6ea5835e2.jpeg


Since when did Kalgoorlie have ARFF? Yet another inaccuracy in an ATSB report!


https://cimg0.ibsrv.net/gimg/pprune.org-vbulletin/1170x1716/img_5321_7e42a72a0c9c71f7bc28ecdec1f1f0faf4150376.jpeg

[wwel]

Wow, that's quite the sop deviation by the flight crew.

Reading the pilot experience section of the report, it appears that the First Officer had "around 1800hrs of total flying experience" and only held a CPL Licence.

I wonder if a more experienced First Officer who had previous experience flying narrow body jets for other airlines would have questioned the decision to blindly follow the engineers instructions rather than use their own checklist. Or would maybe have thought to scan the overhead panel after a maintenance procedure was completed to ensure that all the switches were where they should be. I know what kind of FO I would prefer in the cockpit in that situation.

Perhaps the decisions of the QF "Talent Acquisition" people in recent years are starting to bite the company on the arse. I can't say that I didn't see it coming. There are pilots with plenty of experience on narrow body aircraft with other airlines that have been getting turned away from QF, some without even an interview. Boggles the mind.

[SHVC]

The whole report reads inaccurate or, the PIC have a messed up time line. When did the fuel transfer actually start? When the captain returned to the flight deck or when the captain was still outside the crew don’t seem to know which is odd. If only the CVR was not overwritten. And I don’t know, for a checkie to not be able to identify a fuel leak by simply referancing FOD before take off from their fuel check, fuel loaded and fuel used is concerning also. All of this could have been avoided easily.

[framer]

for a checkie to not be able to identify a fuel leak by simply referencing FOD before take off from their fuel check, fuel loaded and fuel used is concerning also.
I’m not making comment on how this was handled one way or the other, but I do think that fuel imbalances and leak identification on the 737 is something that is more difficult than most people assume. I’m not sure why this is the case, I have experienced confusion when trying to determine if we have a leak and my takeaway is that the pilots have to be very very diligent and methodical in stepping through the checklists and that the (totaliser fuel + remaining fuel) calculation is rarely going to be perfect, two or three hundred kg’s is to be expected. I take a ‘there but for the grace of God…’ approach to it.
​​​​​​​Does anyone know if there was visible moisture/ precipitation at the field on the day?

[43Inches]

I’m not making comment on how this was handled one way or the other, but I do think that fuel imbalances and leak identification on the 737 is something that is more difficult than most people assume. I’m not sure why this is the case, I have experienced confusion when trying to determine if we have a leak and my takeaway is that the pilots have to be very very diligent and methodical in stepping through the checklists and that the (totaliser fuel + remaining fuel) calculation is rarely going to be perfect, two or three hundred kg’s is to be expected. I take a ‘there but for the grace of God…’ approach to it.
Does anyone know if there was visible moisture/ precipitation at the field on the day?

I'd have to agree there with that in regard to a number of aircraft types. I think you have to really take time to identify a fuel leak unless it's brutally obvious, like fuel streaming out of the wing. You need to know your fuel system inaccuracies before the event, then see repeated corrected imbalances or signs that a large imbalance is occurring. Just stopping flow from the tank may not show a leak in the system from the tank to engine, so the fuel could be leaking from a point between the tank and engine. Then there is the differences between totalizers and actual indications, vs a lot of factors that make it very difficult to detect a small leak.

If no obvious leak, correct the imbalance, even if it's not safety related it will affect efficiency of operation. Then if it goes out of balance again really look at the numbers and the trend, follow the QRH advice and so on.

​​​​​​​Reading the pilot experience section of the report, it appears that the First Officer had "around 1800hrs of total flying experience" and only held a CPL Licence.

I wonder if a more experienced First Officer who had previous experience flying narrow body jets for other airlines would have questioned the decision to blindly follow the engineers instructions rather than use their own checklist. Or would maybe have thought to scan the overhead panel after a maintenance procedure was completed to ensure that all the switches were where they should be. I know what kind of FO I would prefer in the cockpit in that situation.

Low time pilots if trained correctly are usually better at following SOPs, and therefor checklists, as they don't have experience as such to fall back on. If low timers are not following their failure management routines properly then that smells of systemic issues in training.

[SHVC]

I’m not making comment on how this was handled one way or the other, but I do think that fuel imbalances and leak identification on the 737 is something that is more difficult than most people assume. I’m not sure why this is the case, I have experienced confusion when trying to determine if we have a leak and my takeaway is that the pilots have to be very very diligent and methodical in stepping through the checklists and that the (totaliser fuel + remaining fuel) calculation is rarely going to be perfect, two or three hundred kg’s is to be expected. I take a ‘there but for the grace of God…’ approach to it.
Does anyone know if there was visible moisture/ precipitation at the field on the day?

My point was not to berate the crew. I believe there is a lot more questions than the handling of this, but I won’t get o to that. Was a 3% check carried out after refueling? The report doesn’t mention it, the captain doesn’t mention it! I find that weird not to be included in the report, I would be curious to how thick the CSFF was in late after noon in October in Perth seems the engineer made no attempt to ascertain the thickness!

I don’t fly the 737 I can assume there is a fuel system page? FOD on the MCDU or equivalent or FOD on flight plan as a minimum. Looking at what’s in the tanks looking at what has been used then referring to the fuel check after a 3% calculation after the refueling was complete for FOD this could have been easily avoided or rectified in the air using the checklist Numbers in the tanks will always be the same after fuel check on the ground. Unless there is an actual leak it won’t add up. Diligence with fuel management is one of the most important aspects of our job, just in this case it was not.

[Transition Layer]

Does anyone know if there was visible moisture/ precipitation at the field on the day?

Historical METAR data would suggest there were showers on and off all afternoon, temps in the mid teens.

https://cimg8.ibsrv.net/gimg/pprune.org-vbulletin/2000x840/img_0304_76b2ccb86bc33073e7c06475243011d053c69296.jpeg
​​​​​​​

[maggot]

My point was not to berate the crew. I believe there is a lot more questions than the handling of this, but I won’t get o to that. Was a 3% check carried out after refueling? The report doesn’t mention it, the captain doesn’t mention it! I find that weird not to be included in the report, I would be curious to how thick the CSFF was in late after noon in October in Perth seems the engineer made no attempt to ascertain the thickness!

I don’t fly the 737 I can assume there is a fuel system page? FOD on the MCDU or equivalent or FOD on flight plan as a minimum. Looking at what’s in the tanks looking at what has been used then referring to the fuel check after a 3% calculation after the refueling was complete for FOD this could have been easily avoided or rectified in the air using the checklist Numbers in the tanks will always be the same after fuel check on the ground. Unless there is an actual leak it won’t add up. Diligence with fuel management is one of the most important aspects of our job, just in this case it was not.
I don't fly the 737 but... 😂

Historical METAR data would suggest there were showers on and off all afternoon, temps in the mid teens.

https://cimg8.ibsrv.net/gimg/pprune.org-vbulletin/2000x840/img_0304_76b2ccb86bc33073e7c06475243011d053c69296.jpeg


A very fair case for 'getting onto' a transfer asap before the refuelling makes it more complicated. CSFF is a right pain on the old slug the engineers most often handle this rectification. If getting off a jet in a likely CSFF situation I'll let the ginger beer know and they'll look - hell, I've been told it's frosted as they plug in before. It's difficult to consider thickness as it can change after you look at it thus its conservative to do a transfer and get ahead of things.

​​​​​​​NNCs assume normal switching.

[maggot]

I’m not making comment on how this was handled one way or the other, but I do think that fuel imbalances and leak identification on the 737 is something that is more difficult than most people assume. I’m not sure why this is the case, I have experienced confusion when trying to determine if we have a leak and my takeaway is that the pilots have to be very very diligent and methodical in stepping through the checklists and that the (totaliser fuel + remaining fuel) calculation is rarely going to be perfect, two or three hundred kg’s is to be expected. I take a ‘there but for the grace of God…’ approach to it.
Does anyone know if there was visible moisture/ precipitation at the field on the day?
​​​​​​​Notably the occurrence was after CWT exhaustion, notorious for throwing the numbers out a few hundred too

[maggot]

Wow, that's quite the sop deviation by the flight crew.

Reading the pilot experience section of the report, it appears that the First Officer had "around 1800hrs of total flying experience" and only held a CPL Licence.

I wonder if a more experienced First Officer who had previous experience flying narrow body jets for other airlines would have questioned the decision to blindly follow the engineers instructions rather than use their own checklist. Or would maybe have thought to scan the overhead panel after a maintenance procedure was completed to ensure that all the switches were where they should be. I know what kind of FO I would prefer in the cockpit in that situation.

Perhaps the decisions of the QF "Talent Acquisition" people in recent years are starting to bite the company on the arse. I can't say that I didn't see it coming. There are pilots with plenty of experience on narrow body aircraft with other airlines that have been getting turned away from QF, some without even an interview. Boggles the mind.
Hmmmm does talent look at comprehension? You seem to be missing an important detail from the report in your damning assessment of the FO

[framer]

Thanks for the weather information Transition Layer.
The ice needed to be gone.
I generally like ATSB reports for the extra tech information in them but this one could have done with the very basics of weather information to help build a complete picture.
Thanks again.