Boeing 737-8FE vh-yie

[Bosi72]

https://www.atsb.gov.au/publications/investigation_reports/2021/aair/ao-2021-031/

>.... The autothrottle then also disengaged for reasons undetermined....

I think Boeing software needs some serious audit..

[drpixie]

When in doubt, fly the f**** aircraft - which the crew did, and all ended well.

[big buddah]

https://www.atsb.gov.au/publications/investigation_reports/2021/aair/ao-2021-031/

>.... The autothrottle then also disengaged for reasons undetermined....

I think Boeing software needs some serious audit..

Haven’t read the report but the highlights said a circuit breaker popped, so what’s the issue you have with the B737-800 software?
Looks like everyone did a good job.

[Bosi72]

Haven’t read the report...

Maybe read the report ?

[Shane Sanders]

Maybe read the report ?
The report that doesn't exist because it was discontinued?

[Lookleft]

A good scenario for Command candidates. I also wonder how this scenario would fit into the pilotless flight deck narrative.

[Bosi72]

Nobody questions crew actions.

If the issue cannot be replicated and the cause is undetermined, would you agree something (and more) has to be done other than "continue to monitor"?

Here is similar incident involving zs-sjd from 2 years ago. The cause was also undetermined, however the report provides more details.

https://www.google.com/url?sa=t&source=web&rct=j&url=http://caa.co.za/Accidents%2520and%2520Incidents%2520Reports/1281.pdf&ved=2ahUKEwiM9_Gq9pDzAhWyIbcAHZZiAGMQFnoECBcQAQ&usg=AOvVaw2m3n0ccdeVAEYjTLa31cnc

[Capt Fathom]

Bosi72. Next time you board an airliner, will it be a Boeing or an Airbus?

[Angle of Attack]

If you’ve ever flown 737 the bloody autopilot and auto throttle does disconnect at random times, that has probably been the way since the 1960’s, however in the NG it does seem to be somewhat less than the classic 737’s, I read this as nothing to do with software, there was a popped circuit breaker was there not?

[Bosi72]

..will it be a Boeing or an Airbus?
It will be whatever the airliner flies.

As a pilot (and software engineer), I would like to know what causes any intermittent and unresolved issues.
Circuit breaker is mostly the last safety in the chain of events and is rarely root cause of an issue.

Also, replacing the light that works(shine) doesn't make sense to me. The light that does not work is usually replaced, not the other way.

This post has nothing to do with politics, conspiracies, whatever. Simply suggesting Boeing to audit the software, meaning put extra logging which could provide more information and hopefully lead to resolution.

[TimmyTee]

Your experience with the inner workings of a 737 (or any commercial jet) is how many hours/years/flights as a professional punter Bosi72?

[galdian]

I'd just be interested to have confirmed that in addition to any NNC's a thorough scan of the CB panels was conducted.
Always been an "assumed will be completed" task within Non Normal ops but is not restated/reinforced after the general statement in the NNC introduction.

Especially once an additional crewmember was in the flightdeck you'd hope an initial/additional CB check would have been conducted, spotting any popped CB's always been a challenge on the 737.

Had a popped CB been found and a successful reset attempted that might have been the end of the story and a far more comfortable flight for the flightcrew completed.

[PPRuNeUser0184]

Sigh......PPRUNE used to be a forum for professionals.

[Buttscratcher]

Bit harsh there KZ.
Galdian has a point.
You’d have to feel like a bit of a dick if you handflew the thing for 4 hours because of a tripped CB. I don’t fly the maggot, but I’m guessing one CB wouldn’t have caused 2 APs and ATs to fail with no redundancy.
The report was somewhat vague in that respect.

[BuzzBox]

Had a popped CB been found and a successful reset attempted that might have been the end of the story and a far more comfortable flight for the flightcrew completed.

I appreciate the B737 is an 'antique' in many respects, but at the outfit where I flew (non-B737), resetting a tripped CB in flight was prohibited unless it was part of an FCOM procedure and the consequences of doing so were clearly understood. On some aircraft the systems protected by a CB may not be obvious and resetting a tripped CB might have unintended, serious consequences.

[The Banjo]

What Buzzbox said is very correct.
With what authorisation do you reset the circuit breaker in flight?? If it the reset is not covered in the reset table, abnormal checklist etc you don't touch it. CASA would deem a reset outside of this to be unauthorised maintenance and would do you slowly..

[galdian]

As now pretty much retired don't have the NNC in front of me, last I knew in the intro - and only in the intro - it discussed CB's.
Generally one reset of a tripped CB was permitted.
No reset of a fuel CB was permitted.
Cannot remember if fuel CB was part specific (eg FUEL PUMPS) or the fuel system in general.
Apologies if procedural changes in the last couple of years.
Cheers.

And be reasonable - BuzzBox was talking SOP about non-737 aircraft, maybe interesting but not relevant.
And "reset table"? Never heard of such a thing on 737. Comment was in reference to 737 SOP (maybe company SOP) I assume?

[big buddah]

I’m still trying to work out what the original poster wants. The aircraft had a A/P and auto throttle failure. TAWS works as it should, don’t sink. The crew followed the QRH continued flight to the destination advised non rvsm etc asked for a block. didn’t reset CB’s as not recommended by Boeing in this procedure.
Engineering resets and test ok
ATSB says good job to the crew.

Fo goes to the bar and tells the girls how amazing he is.

[PoppaJo]

I appreciate the B737 is an 'antique' in many respects, but at the outfit where I flew (non-B737), resetting a tripped CB in flight was prohibited unless it was part of an FCOM procedure and the consequences of doing so were clearly understood. On some aircraft the systems protected by a CB may not be obvious and resetting a tripped CB might have unintended, serious consequences.

Many don’t that’s the problem.

AirAsia 8501 is a report that should be read by all. Go playing around with CBs and it all falls apart pretty quick.

Interesting the CP let them continue. I can’t say mine would have, on the ground please let the engineers deal with it sort of comes to mind.

[BuzzBox]

As now pretty much retired don't have the NNC in front of me, last I knew in the intro - and only in the intro - it discussed CB's.
Generally one reset of a tripped CB was permitted.
No reset of a fuel CB was permitted.
Cannot remember if fuel CB was part specific (eg FUEL PUMPS) or the fuel system in general.
Apologies if procedural changes in the last couple of years.
Cheers.

And be reasonable - BuzzBox was talking SOP about non-737 aircraft, maybe interesting but not relevant.
And "reset table"? Never heard of such a thing on 737. Comment was in reference to 737 SOP (maybe company SOP) I assume?


The standard Boeing spiel says:
In flight, flight crew reset of a tripped circuit breaker is not recommended. However, a tripped circuit breaker may be reset once, after a short cooling period (approximately 2 minutes), if in the judgment of the Commander, the situation resulting from the circuit breaker trip has a significant adverse effect on safety.

However, our Ops Manual specifically prohibited the resetting of a tripped CB in-flight.

Airbus aircraft have a reset panel on the overhead panel with 'buttons' that can be used to reset various systems after consulting the QRH. Hence the 'reset table'.

[galdian]

BuzzBox
The Standard Boeing spiel or the Standard Boeing 737 spiel?

PoppaJoe
Since when is following SOP - IF this still remains the SOP for B737 - "playing around with CB's"? You discuss, if you see no adverse consequence you're allowed one reset attempt as per NNC (assuming not countermanded by any Company instructions).
Rather sweeping statement as well "touch a CB and the aircraft will crash everytime" inference. And I thought AirAsia operated Airbus not Boeing but who cares - all the same procedures apparently.

big buddah
"Didn't reset CB as not recommended by Boeing in this procedure..." could you please clarify the NNC item specifically mentioned CB's or just your interpretation of the CB notes in the NNC introduction?

As before if procedures have changed for the B737(NG in this case) I'm happy to stand corrected.

[BuzzBox]

BuzzBox
The Standard Boeing spiel or the Standard Boeing 737 spiel?

My understanding is that it's standard wording across all Boeing types. The quote was taken from a B777 QRH that's about two years old. A B737 QRH from about 10 years ago says the same thing. The B747 QRH is similar, but also prohibits the resetting of fuel pump CBs.

[galdian]

My understanding is that it's standard wording across all Boeing types. The quote was taken from a B777 QRH that's about two years old. A B737 QRH from about 10 years ago says the same thing. The B747 QRH is similar, but also prohibits the resetting of fuel pump CBs.

OK thanks, the 737 spiel also included prohibiting resetting of the fuel pump CB's, other than that one reset allowed; of course at Captain/Command decision but a reset is not prohibited.

[Potsie Weber]

Why did they enter RVSM airspace with inoperable autopilots?

[Capt Fathom]

Why did they enter RVSM airspace with inoperable autopilots?

Via an ATC Clearance?

[Potsie Weber]

Via an ATC Clearance?

According to the report, they notified ATC they could not meet RVSM requirements once in cruise, but the requirements for RVSM (automatic altitude hold system) must be met before entering RVSM airspace. They had the problem before they entered RVSM.

[Capt Fathom]

It's a very abbreviated report.....

The ATSB found that at all stages of the flight, the flight crew acted in accordance with operator’s and aircraft manufacturer’s procedures, and had considered and managed the risks associated with continuing the flight.

[Lookleft]

If you declare that you are non-RVSM it does not prevent you from operating in RVSM airspace, but ATC may not give you a clearance. As this event occurred this year I doubt that other traffic was going to be a problem especially as they were given a block clearance. had they been denied a clearance into RVSM airspace then I doubt that they would have had the fuel to go to Brisbane. I think that the way this was handled shows the results of years of CRM and TEM training. Positive outcome and it appears as though the crew have gone through the problem and mitigated the threats. The fact that the report has been discontinued suggests that the ATSB does not see the benefit of using resources where there is no safety benefit. Essentially the crew were faced with a technical issue, they handled it, the aeroplane was landed safely. End of story, the way the system is supposed to work.

[deja vu]

According to the report, they notified ATC they could not meet RVSM requirements once in cruise, but the requirements for RVSM (automatic altitude hold system) must be met before entering RVSM airspace. They had the problem before they entered RVSM.
RVSM really shouldn't apply in Australia, except maybe MEL-SYD_BNE at peak hours. So Potsie suggests they should have cancelled the flight because they may not meet the requirements of reduced separation operations in a country that is totally empty of aircraft?.They did exactly the right thing. Incidentally I have never heard of management or engineering encouraging a turn back regardless of the severity of the problem.

[galdian]

RVSM really shouldn't apply in Australia, except maybe MEL-SYD_BNE at peak hours. So Potsie suggests they should have cancelled the flight because they may not meet the requirements of reduced separation operations in a country that is totally empty of aircraft?.They did exactly the right thing. Incidentally I have never heard of management or engineering encouraging a turn back regardless of the severity of the problem.

Don't disagree but:
- the rules do exist
- the report itself said they only reported the inability "in the cruise" inferring they entered RVSM knowing they couldn't meet the requirements to enter RVSM airspace.

I expect they obtained clearances - or at least understanding from ATC - before passing FL290 and ATC said "yeah, f**k all traffic, we'll make it work".

Only Q then would be whether /under what circumstances ATC can vary "the law", an aircraft in distress once in RVSM airspace is different from an aircraft that knowingly enters that airspace without meeting the requirements.
Mention solely as my early days in Japan something standard in Oz - cancel 250kt below 10.000' - ATC could not authorise for normal operations as was "against the law".

[Capt Fathom]

Pelair operated their Westwinds non-rvsm for years. Most times they would get their requested level. Sometimes they would not.
It was up to ATC to either accept or reject the request.

[Potsie Weber]

RVSM really shouldn't apply in Australia, except maybe MEL-SYD_BNE at peak hours. So Potsie suggests they should have cancelled the flight because they may not meet the requirements of reduced separation operations in a country that is totally empty of aircraft?.They did exactly the right thing. Incidentally I have never heard of management or engineering encouraging a turn back regardless of the severity of the problem.

Not suggesting that at all. Only questioning whether they followed the RVSM rules. Simply advise ATC before FL290 that you are non RVSM and let ATC decide if there is traffic around that may restrict or delay operating non-RVSM in RVSM airspace. It’s not that hard.

[deja vu]

Not suggesting that at all. Only questioning whether they followed the RVSM rules. Simply advise ATC before FL290 that you are non RVSM and let ATC decide if there is traffic around that may restrict or delay operating non-RVSM in RVSM airspace. It’s not that hard.
Well yes in hindsight its all so clear. So at F/L180 AP A disengages, A/T also disengages, they select B AP soon after and then that disengages later, the Stab trim light comes on, they monitor the problem, they run checklists, they call engineering and management and finally accept they are not going to have an autopilot and requested a block altitude to complete their flight. True, the rules must be obeyed, maybe they prioritised their task, maybe it didn't occur to them that when entering RVSM they couldn't restore the autopilot, because they were fully occupied whatever, who knows.? The last thing they needed is pedantic criticism.

[neville_nobody]

According to the report, they notified ATC they could not meet RVSM requirements once in cruise, but the requirements for RVSM (automatic altitude hold system) must be met before entering RVSM airspace. They had the problem before they entered RVSM.

You should go work at CASA with an attitude like that. They told centre they were non-RVSM, if it wasn't going to work Centre would have just said 'clearance not available descend now' etc etc. They may have also been RVSM compliant on the way up but not at the cruise. Noone knows and it really doesn't matter. They flew the aeroplane and that is all that matters. Only in Australia would someone be worried that you may or may not have broken the AIP for a couple of minutes.