What Am I Looking At: 3 Questions in Oil Analysis

John Ross

What Am I Looking At: 3 Questions in Oil Analysis

I promise this is an article on oil analysis.

“Captain Ross,” the colonel yelled as he held up a freshly unearthed piece of metal. “What am I looking at?”

“Colonel, that’s part of the right rear strake,” I told him while adjusting my chemical warfare gear.

One hundred miles behind the Republican Guard during the Gulf War was not a place you could hurry to get your chem-gear on if you had to. Not for an Air Force officer, very unaccustomed to being this close to the enemy or to carrying an M-16.

“How do you know?” the colonel asked while examining an almost indistinguishable hunk of junk.

“Because,” I said, “I know every single part of this airplane.”

The airplane was a crashed Air Force asset, currently spread out over two miles of unforgiving wasteland that was now ours to investigate. We had about eight hours on the ground before the Navy Seals came back for us.

One hundred miles behind enemy lines, a lost aircraft, two miles of scattered and charred evidence, wearing full chem-gear, five Air Force officers (with guns), eight hours on the clock, and we had to figure out why this plane crashed.

No pressure.

We didn’t have a lot of equipment, but what we did have was incredible analytical skills. From that spot and piece of airframe, we could reconstruct exactly how the aircraft impacted the ground and came apart. An entire investigation was conducted, reported, and filed and advancements in aviation warfare were made because of the absolute recognition of what we were looking at. 

I don’t have many great war stories, and even fewer that I might use as a pseudo-segue into maintenance and reliability. But, I hope you’ll agree that being certain of what you are looking at can get you closer to a successful conclusion.

How certain are you of what you’re looking at?

Oil Analysis Results: Three Questions to Ask Yourself

I promised an article on oil analysis, but I wanted to introduce the aircraft story because I hope to use it, metaphorically, throughout this message. 

As a near-40-year practitioner of maintenance and reliability, let me cut to the chase. When looking at the results from an oil analysis, the three most important questions to ask yourself are:

  1. What is the condition of the oil?
  2. What is the condition of the additives?
  3. What is floating around in the oil?

I like to think that my ability to analyze evidence is as strong as anyone’s. As one might imagine, aircraft crash investigation training is intense. In a clean, antiseptic classroom, you learn how to forensically piece together “what happened”. One such laboratory recreation was simply the fuel door from an F-16. That’s it. Just the door. Nothing and no one else was ever recovered.

The intent of an official crash investigation is to discover what happened, and, more importantly, to find out how the Air Force can keep it from happening again. No punitive measures can be taken by law. Simply investigate and prevent.

Our oil analysis should pursue a similar path of investigative curiosity and preventive measures. ISO 14224 instructs that “leadership will determine what to measure, how to measure it, and what to do with that measure.” Considering that the lubrication process and systems are in fact “systems,” and perhaps the most important systems of all, wouldn’t it make sense that the leadership use this instruction to calculate the health and performance of the lubrication and its systems?

I think it does.

“Systems” is an important word, as is “performance”. One aspect necessary to conduct a crucial analysis is to understand the system and another important feature is to understand the needed and demonstrated equipment performance.

The Society for Maintenance and Reliability Professionals states in their globally recognized Body of Knowledge that “stakeholders that can influence performance and safety must have a complete process understanding.” This leaves little room to rationalize a substandard understanding of what it takes to make a system or process run efficiently and effectively.

It’s highly unlikely that if your gearbox shells out due to improper lubrication that the consequences will be grave. Imagine that gearbox strapped to a jet aircraft at 48,000 feet traveling at Mach 2. Or worse, as our incident aircraft, traveling 50 feet off the ground at Mach 1+. Not a lot of room for error.

Let’s break down those three important questions to ask yourself when you receive the results from your oil analysis.

Question One: What is the Condition of the Oil?

The results of an oil analysis review should indicate if the oil is up to the task and serviceable. Viscosity is the chief characteristic of a lubricant and the best indicator of the oil’s ability to perform its essential duties, which include:

  • Reducing friction.
  • Absorbing and reducing shock.

When an aircraft is involved in an incident, specifically a crash, all the servicing equipment used on that aircraft prior to launch is impounded for further review. This includes the fuel and lubrication equipment. Also, the investigating maintenance officer will conduct a thorough review of the aircraft records and interview those associated with the aircraft. The purpose is to determine if there is any evidence that the airworthiness of the aircraft was suspect.

Question Two: What is the Condition of the Additives?

Additives are introduced into the lubricant as a way to aid or enhance its inherent features, and an oil analysis should provide great insight into their condition. Common additives include:

  • Rust and corrosion inhibitors
  • Anti-wear
  • Viscosity improvers
  • Anti-foaming
  • Extreme pressure

When considering additives for lubrication purposes, it is vital to also look at the environment the system will be operating in. This means not only understanding the physical environment, but the conditions the additives will be subjected to, such as total hours of continuous operation and the starting and stopping frequencies. By investigating and analyzing the condition of the additives, we can gauge how our entire system is performing.

It’s difficult to imagine a smooth transition into a metaphor for aircraft incident investigations other than to point out that the operating context of the aircraft’s mission must be determined before you can actually conduct an effective evidence analysis. This helps in:

  • Creating alternative scenarios.
  • Determining what evidence might be found at a possible crash site.
  • Creating a plan to make a crash site safe for investigators.

These are just a few examples of things that have added to the complexity of an investigation:

  • Jet Assisted Take Off equipment (JATO)
  • Armaments – bombs and bullets (requires EOD-explosive ordinance disposal)
  • Countermeasures – chaff and flares (both can be extremely dangerous)
  • Dual cockpit configuration, but only one aviator on board, or any configuration of airmen – how many souls on board?
  • Ejection seats (very dangerous if the ejection wasn’t initiated)

We located a TOW Anti-tank missile launcher in the center of the major aircraft material in the incident mentioned at the beginning of this article. An anti-tank missile launcher?

Question Three: What is Floating Around in the Oil?

Evidence of metals or other such debris that is reported in oil analysis findings gives us great insight into what might be wearing or failing. Sludge in a gearbox might be a result of oxidation and could be evidence of the reduction of an antioxidant additive. There is a lot to learn from what’s floating around in the oil.

Below is a short list of where the wear can come from:

  • Aluminum– Pistons, bearings, pumps
  • Barium– Rust and oxidation inhibitor additives
  • Calcium– Detergent/dispersant additives
  • Copper– Bearings, bushings
  • Molybdenum– Excessive pressure additives
  • Iron– Gears
  • Silicon– Dust/dirt, defoamant additives
  • Tin– Journal bearings, bearing cages

There is a very direct comparison between this characteristic and an aircraft crash investigation. If you recall the story that started this article, I was able to quickly and accurately identify the piece of metal my commander had unearthed. I was able to do this, as I explained, because I knew everything there was to know about this airplane. In truth, I really did.

Do you recall the SMRP’s directive in their Body of Knowledge, which I also mentioned earlier? “Stakeholders …must have a complete process understanding.” Our investigation team was able to deduce, in very short order, the complexity of a crash site because we had a complete process understanding. On that team were:

  • commanders
  • pilot members
  • flight surgeons
  • weather officers
  • maintenance officers

Each of us was highly knowledgeable about the systems we were responsible for, to the point that a random piece of wreckage, no longer than four inches, could be positively identified. Not only did we have systems knowledge, we knew that there would be signs of distress, and we knew what to look for. For example:

  • Indicator pointers (needles) in a gauge will make an impression on the inside of a gauge’s glass to show their position upon impact.
  • Broken light bulbs that are on during impact will leave a light layer of soot inside the remaining glass.
  • If a jet engine is running upon impact, the compressor’s fans will be bent in the direction of rotation, and there will be dirt (or ground debris) throughout the engine.  

Just like the tell-tell signs of component wear found in oil analysis comes from what you find floating in the oil, the tell-tell signs of an aircraft crash investigation can be found by analyzing the evidence provided by the “little” things.


Sadly, our entire investigation was further thrust into the spotlight to determine an absolute root cause because of our uber-limited resources. At the time, this was a highly classified aircraft. Both pilots were lost in the accident, and the entire mission was conducted under classic radio silence. All we had was the evidence on the ground and the piecing of other forensic evidence.

This loss was catastrophic.

There was one tiny factor that could have altered the events of that day. I’m not at liberty to divulge this factor, but it would have been a turning point. A difference maker.

This is truly a poor transition, but I want to bring this point home. Each day we get another piece of the puzzle. If we are tracking and trending what will be “evidence” to an investigator, how much better and more focused are we going to be knowing that we could avert disaster?

Do we know our systems and processes well enough to recognize the significance of the insignificant?

Do we have a complete understanding of the process and systems?

Anything less than complete and comprehensive won’t get it done in the 21st Century.

I probably don’t know you. The fact is, I’d hate for us to meet for the first time while I’m sitting in your boardroom, looking at you and wondering if you knew what you were looking at?

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About the Author

John Ross, President of Maintenance Innovators has been a practitioner of maintenance and reliability for over three decades. A former Captain in t...