ATSB....Is this another dud report? Power Loss at night in NT

[Jabawocky]

http://www.atsb.gov.au/media/4027718...2092_final.pdf

Please correct me if I am wrong, but as I understand it, this aircraft had an engine failure, and the outcome was lucky and executed with some skill.

The report tells a story, but it fails to detail the one very serious reason that caused the incident.

We all read things hoping to take something away from it, when you read this there are some good reminders to keep in mind when flying at night in remote areas. But, there is something missing here.

The trusty Lycosaurus is a reliable animal, and we all recognise the greatest number of engine failures are usually a result of fuel being replaced with air!

So if my suspicions are correct, and I have good reason to think they are, this aircraft suffered from a loss of oil, due to not a leak, but consumption, perhaps not normal consumption but one at the extreme end of the "acceptable" range. The aircraft I believe had flown a lot of hours that day/night and nobody had replenished this one vital fluid. Perhaps not even at the beginning of the day? Who Knows? Nothing in the report about anything relating to this.

So if this suspicion is correct, why would the ATSB not pay any attention to the real cause of the failure. Poor Pilot/operator attention to detail.

The report makes not mention of the engine health, hours since OH/new, nothing of its maintenance records or daily uplift of oil in the recent past.

So, unless I am confusing this incident with something else, we have yet another very poor performance by the ATSB on a piston engine failure. Even if this flight is not the one I think it may be, the report is still very lacking in anything remotely like a report should be for an engine failure, and one typical of the entire GA fleet.

I am seriously thinking the Australian Government would get far better value for money, and spend less by closing CASA and ATSB (aviation related at least) and sub contract it all to the FAA/NTSB.

Yet another disgrace. Feel free to be critical of my thoughts and correct me if I am wrong about this incident.

For some reason this report "changed" location http://www.atsb.gov.au/media/4019056...2092_final.pdf here is the new one.

[blackhand]

So if my suspicions are correct, and I have good reason to think they are, this aircraft suffered from a loss of oil,

Looking at the big hole in the crankcase it was a massive and instantaneous oil loss. the report says it was a big end cap bolt failure. You are looking for and finding fault where none exists

[Old Fella]

Report. Dud or not?

The report certainly is short on detail in terms of EHSO for the powerplant, or any other info. It does however clearly show the damage suffered by the engine as a result of the Bigend Bearing Cap bolt failure. There was a period of about 35 minutes between the first observation of lower than normal oil pressure and where it had dropped sufficiently to prompt the crew to make a precautionary landing. Another 5 minutes elapsed before the "Low Oil Pressure" light illuminated. No mention anywhere about higher oil temp, which one would reasonably expect to see, if falling oil quantity was the root cause of the falling oil pressure.

On the other hand if the bigend bearing cap bolt was gradually stretching, which would increase the bearing to crank clearance, one could expect the oil pressure to slowly fall as the clearance increased. The eventual failure of the bolt would cause a complete loss of oil pressure. The degree of damage certainly indicates a sudden and unanticipated mechanical failure.

As Jabawocky said, we all hope to learn from these reports. The only real lesson in this report is that the PAL system will not always work as advertised.

[Creampuff]

C’mon Jaba, safety is being enhanced all across the nation by the knowledge that:

- “the failure was a result of a No. 6 connecting rod, big end cap bolt failure”, and

- “responding to an adverse situation promptly can result in a positive outcome”.

My pre-flight checklist will now include “Check No. 6 connecting rod big end cap bolt” (using x-ray vision).

My emergency checklist will now include “Response: Prompt”, just under Douglas Adams’ invaluable advice “Panic: Don’t”.

BH: How does 1920 to 2000 – some 50 minutes – constitute ‘massive and instantaneous oil loss’?

At about 1920 Central Standard Time (CST), when maintaining 7,500 ft above mean sea level (AMSL), the crew noticed that the engine oil pressure indication was slightly lower than normal.

The crew continued to monitor the oil pressure and, at about 1955, having noted the pressure dropping further, they began planning for a diversion to the Ti Tree aeroplane landing area (ALA). The instructor had flown into the ALA the previous week and reported using the pilot activated lighting (PAL) system without any issues. The crew relayed their intentions to air traffic control (ATC) via VH-XGN, a Cessna 310 cruising in the vicinity at a higher altitude.

At about 2000, the engine oil pressure light illuminated, necessitating an immediate landing.

Bolding added.

The engine then began to ‘run rough and subsequently stopped’.

[blackhand]

BH: How does 1920 to 2000 – some 50 minutes – constitute ‘massive and instantaneous oil loss’?

That would be because the oil level was OK, until the rod punched a hole through the case. Up till then the oil presure was decreasing as No. 6 journal clearance was increasing.

[Creampuff]

You may be correct.

If only the ATSB had put aside 10 minutes to ask and report on the pilot’s answers to the questions: What was the oil level when you dipped it? What was the oil temp indication during the period 1920 through to the decision to land? And, if an engine monitor was fitted to the aircraft: “What were the CHT and EGT indications during the period 1920 through to the decision to land? (The ATSB might even been able to download the lot (other than the oil level) from the engine monitor!)

Serious question, and purely hypothetically. Let’s say I take off in a fairly standard 6 cylinder, normally aspirated Lycoming or CMI engine, and with “just enough” oil, what are the symptoms and consequences as the oil falls below “just enough” and continues falling below the minimum (assuming we’ve enough fuel to keep flying until and beyond that point)?

[Jabawocky]

Come on guys... you are all better than this. Talk about Hook Line and Sinker.

Read my post again....read the report again.

Remember, I ampretty sure the reason for the oil pressure problem is known to several experts involved. Unless I have the wrong incited. But I am pretty sure I have not.

You are looking for and finding fault where none exists

No I am not. Where is the logical path that lead to that component failing. Was it a metallurgical fail? Was it lack of oil? If lack of oil pressure was it a pump failure? Was it an oil cooler leak....etc.

Think a bit further. Even If I am wrong about which Airvan had a failure like this and it was because it burned up all the oil in the sump, this report went nowhere near detailing what happened.

Old Fella

No mention anywhere about higher oil temp, which one would reasonably expect to see, if falling oil quantity was the root cause of the falling oil pressure.

Most of your post I can agree with, but this statement is an Old Wives Tale. This depends on a lot of things, and low oil level will not often show an increased temperature. It will eventually once the level gets really low start showing up as oil pressure issues.

blackhand

That would be because the oil level was OK, until the rod punched a hole through the case. Up till then the oil presure was decreasing as No. 6 journal clearance was increasing.

Or pehaps the more likely scenario of the oil pressure was fine until it started to drop due to insufficient oil, and then the oil pressure failed and a warning light said so. engine is still running but starved of oil. Then the big end bearing fails. After that of course the engine stops rotating, and thus no more bearings fail (even if they were about to) and given all the damage is at the top of the case, the oil remaining would still be in the sump.

But was there any??? I believe there was not and for a good reason. The ATSB have done nothing to give any credibility to this report, I doubt the engine went to a suitable engine shop, and the photo's supplied were clearly not taken with any forensic purpose in mind at all. If there were some, they did not publish them.

A joke of a report, even if my thought on the cause of the failure is very wrong.

[VH-XXX]

If nobody is hurt, they don't seem to care.

[blackhand]

Conrod bolts do not snap due to oil issues.
Its to do with manufacture or fitment.

Symptom of very low oil level
High oil temp
Prop hunting
You can think of more

[Back Pressure]

An aero engine blows up in flight, and the ATSB don't do any analysis whatsoever ? No safety implications at all ?

Why do a bloody investigation/report if the first place if they were going to come out with such garbage ?

[blackhand]

ATSB don't investigate everything

About this report Decisions regarding whether to
conduct an investigation, and the scope of an investigation, are based on many
factors, including the level of safety benefit likely to be obtained from an
investigation. For this occurrence, a limited-scope, fact-gathering
investigation was conducted in order to produce a short summary report, and
allow for greater industry awareness of potential safety issues and possible
safety actions.

[compressor stall]

Why is there the word "draft" at the footer of P1?

[Jabawocky]

It is meant to be a final report?

[Old Fella]

Old wives tales (not tails Jabba)

Jabba, Engines carry oil of sufficient quantity to not only lubricate the engine, but also to carry engine heat away via the oil cooler. I think my over fifty years in aviation, many hours as a Flight Engineer as well as a background in ground engineering in the engine trade taught me a fair bit. One of the lessons learned is that decreasing oil quantity leads to increased oil temperature which in turn leads to loss of oil pressure. No Old Wives Tale Jabba, just experience.

[Back Pressure]

blackhand, I am well aware that ATSB don't investigate every incident/accident, and I understand why, but in this case, we have an engine die in flight due to a failed big end cap bolt.

General questions:

Surely the ATSB would want to know why ? Did it fail due to overheat from lack of lubricant ? Or due to a manufacturing or material defect ? Wouldn't they examine all the end cap bolts from the engine to see if there may be a faulty batch ? Been heard of before (Lyco cranks). And if they actually did do this, then why was it not in the report ?

Another point: what "potential safety issues and possible safety actions" in this report are going to "allow for greater industry awareness" ? That you can land on a road in the outback ? That the PAL at Ti Tree is cactus ?? A NOTAM is surely the more appropriate and effective way of doing that.

Who here would expect a pat on the back from the boss if you had written such an uninformative and irrelevant report of any topic, let alone one such as this ??

And yes, "Draft" at bottom of p1. Professional or what

Jaba, seems to be a final report. Nothing except my previous sentence to indicate otherwise.

[Jabawocky]

Jabba, Engines carry oil of sufficient quantity to not only lubricate the engine, but also to carry engine heat away via the oil cooler. I think my over fifty years in aviation, many hours as a Flight Engineer as well as a background in ground engineering in the engine trade taught me a fair bit. One of the lessons learned is that decreasing oil quantity leads to increased oil temperature which in turn leads to loss of oil pressure. No Old Wives Tale Jabba, just experience.

What you are saying is correct in that oil carries away heat, no argument whatsoever. However depending on where the temp sensor is, and a whole heap of things, in an aero engine this supposition of a considerable and noticeable long term temperature indication id false. We have data files to show this. Only a small rise (not enough to trigger an alarm) and not for very long and just prior to failure. So please understand this, you may see a temp rise worthy of not, but chances are it is highly unlikely. If you only see a significant indictation in 1 in 100 events, what are you going to teach people?

Now back to this "work experience kid" report.

Back Pressure, yes indeed many more questions. I doubt this thread will uncover all of them.

I had a long discussion with my good friend and one of the few leading engine builders in Australia, and he once again was shocked and stunned. His ken eye within 2 minutes of reading the report focussed on the best technical evidence included. A phot showing that this is a narrow deck engine, not produced since 1975 or something like that. What was that doing in an Airvan?

How old was this engine, where did the parts come from and when was it assembled last?

Despite what blackhand has said, it is highly unlikely an faulty bolt, poorly torqued bolt or similar defect would have survived more than 20-50 hours, and the time it would take to go from beginning of failure to stopped in the sense of a bolt failure, would be far shorter than the time frame quoted. Without further evidence of the rest of the engine being inspected and photographed, the evidence so far does not add up at all.

So where did this engine come from? How did it become fitted to an Airvan, what was the real story of the oil status.

I am not the slight bit interested in persecution of the operator or anyone else. But there is much to be learned from when people almost died. The fact they did not is nothing short of very lucky. And to say that because nobody died it does not warrant the same level of investigation is criminal. Nobody died in the QF32 incident, why such a thorough report?

This is right up there with not recovering FDR/CVR's from the Westwind, the Mojave and Whyalla. I bet there are more buried away.

Be interesting to get another colleagues response to this. Standby for more!

[VH-XXX]

That ATSB picture is definitely not showing a first life factory fitted 540 from Gippy Aero that's for sure. They don't come in navy blue for starters.

[glen beard]

Not only is it not a factory engine,its an old style narrow deck 540 that was dis-continued years ago.(Look at the cyl hold-down nuts). one could only guess what history it had,but most probably out of old PA32-300 which used same engine.

Glen Beard

[Clearedtoreenter]

Well yes, one is certainly left with a feeling of 'is that it then? Engine just stopped due to a random failure of a bolt?'

Whether or not it is a bodgey old engine, (as seems possible) the public at least need to know how it got to be flying in that aircraft and it's overhaul history.

Surely it would not be too difficult to put that information together?

[prospector]

BH: How does 1920 to 2000 – some 50 minutes – constitute ‘massive and instantaneous oil loss’?

Maybe in the ten missing minutes funny things happened?