This maintenance controller learned a difficult lesson about the danger of making assumptions.
This is a story of honest errors, followed by delayed and dumb decisions. A story of mistakes and human error.
Enter, me, the highly qualified and experienced maintenance controller. I had never made a serious error in my 45‑year career as an engineer, including my time spent as a maintenance controller.
We all make mistakes, but this was a big one. In fact, it was a series of big ones.
Several years ago, I took over the maintenance control of a helicopter for a certificated operator. I reviewed the logbooks as part of inducting the aircraft, and all appeared to be in order.
There were, as almost always, many out-of-phase maintenance items, which needed action at various points in the future.
The major component items were listed in the logbook, but some “additional items”, which also required replacement, were not.
Why not? I don’t know, but that’s not the point – they still needed to be replaced.
Something wasn’t right here…
A few days later, we carried out a check on the machine and were completing the relevant log entries when an engineer noticed that a component, a hydraulic pump, was well overdue for overhaul. What’s worse, it was plainly entered in the components section of the logbook.
A review of the maintenance control spreadsheets on the computer told the story – the hydraulic pump was not in the spreadsheet at all!
This was a shock, indeed. How could this have been missed?
Bleedin’ obvious
The answer was simple. I’d been using a generic spreadsheet previously given to me by an associate. I believed it was appropriate to this type and model of machine, but the hydraulic pump in question wasn’t on there.
When I inducted the aircraft and entered the machine’s details into my pre-prepared spreadsheet, I failed to notice that I hadn’t entered the hydraulic pump, despite it being plainly listed in the logbooks.
I had totally missed the bleedin’ obvious.
It was a classic human error. All the information was there in front of me, but I was just filling out a form and not thinking clearly about each entry, and checking it off.
The domino effect
Having identified an issue with my tracking spreadsheet, I decided to review the logbooks and spreadsheet against the maintenance manual. It didn’t take long to discover more errors.
Next up was another expired component, which had been replaced at the correct interval previously, but was now being tracked against a calendar inspection, rather than calendar and hours in service.
Because of the tracking error, the component had been inspected and refitted with a full calendar period to run, then entered in the logbooks and spreadsheet – job done.
Now we had a second expired component!
Once again, I put this situation down to human error. To make things worse, two senior licensed engineers had reviewed the relevant instructions for continued airworthiness (ICA) and confirmed my initial thinking. The first engineer suggested a component had ‘life X’ based on incorrectly interpreted maintenance data. The second engineer listened to the reasoning, checked the same information with the first engineer’s guidance, and almost blindly accepted it as truth.
It’s easy for anyone to see what we expect to see, based on information and an opinion from a respected colleague.
It just kept getting worse
The saga continued and several less critical, but still important, items hadn’t been changed on time. This was because they hadn’t been listed individually in the logbooks, and I’d failed to detect this.
Now we had a neat and tidy spreadsheet on the computer, full of nasty little surprises.
How the hell did we get here?
What I’d usually do when inducting an aircraft as a maintenance controller, would be to audit the records against both the manufacturer and CAA requirements. I’d verify each item one by one, and over the years, I’ve found some equally monumental stuff-ups through this process.
This process, of course, comes at a cost to the client. The client has spent every cent and more buying the machine, and isn’t keen on spending more money on spreadsheets and auditing, especially when they’ve purchased a machine from a highly respected operator.
We see what we expect to see
In the case of this aircraft, three reviews of airworthiness (RAs) had been completed. Nobody had spotted the obvious overdue component, clearly entered in the logbooks.
Two of the RAs were done by the same person, probably using a similar spreadsheet as mine to check component times rather than the ICA. In this case, ‘component A’ was missing.
None of the other items were listed anywhere in the logbooks, so nothing raised a red flag there.
The final RA seemed to have been done by a different person, using the logbooks, who also failed to spot the ‘obvious’ error.
I went back and looked at the logbooks, trying to see why the error may have been missed. In my view, there’s no single clear reason.
The numbers were small in size and, to be fair, I still had to look twice for ‘component A’ to stand out from the others.
It was near the bottom of the page, and there was a list of components above it, all of which had time to run and were due at the same time.
Component A just seemed to blend in, despite it being due at a different time.
Unfortunately, all too often, we see what we expect to see. This is especially true when we’re checking our own work, or the work of someone who we hold in high regard.
How am I going to fix this?
What could I do? I freely admit that I felt a bit panicked, and shocked, by what had happened.
We’ve all experienced the hollow feeling when we realise we’ve made a big mistake. I felt responsible, and a failure. My biggest worry was, “How am I going to fix this monumental stuff-up?”
So I made a list of the items that needed changing and ordered them pronto. One item I found locally, and drove almost four hours to pick it up.
The right thing to do
My next problem was how to tell the aircraft owner. To be honest, I didn’t know what to say. Having always been proud of my reputation and professionalism, I was literally dumbstruck by the situation I’d found myself in.
I did a risk assessment in my mind. My thoughts were that we’d inspected one of the items which was overdue – that one was in absolutely mint condition, and I felt it had almost no prospect of failing.
The machine could operate without too much drama if the other component failed, and the other items presented a lesser risk, so I felt a little better.
In the moment this seemed like a sensible approach, but in hindsight it was a decision made under immense personal and professional pressure.
At that time, it didn’t occur to me that the safest option might be to ground the machine – obvious to you reading this story now.
But then, in the middle of another sleepless night thinking about it, I realised that was the first thing I should have done!
I’d managed to pull apart the whole dirty problem in my head, order parts to fix that problem, and decide that we’d do so as soon as those parts arrived.
So I grounded the machine, which I didn’t like doing. The owner was quite good about it though, which made me feel even worse. However, it was the right thing to do, albeit later than it really should have been.
Here’s what I know now
I fell for commercial pressure and decided not to induct the aircraft fully on arrival.
I justified this decision in my mind, because the machine came from a top operator with a good reputation.
I used a flawed maintenance tracking spreadsheet, which I didn’t check against the aircraft ICA. Had I done an audit on the machine (against the ICA and logbook) when it arrived, I would’ve very likely discovered the missing components.
If I’d done an audit against the ICA, I would’ve also discovered the calendar inspections versus the time-in-service issue. All the big stuff from the airworthiness limitations section was there, but the other items, which had an hours-based life, were not.
I should’ve individually listed the items that hadn’t been done, so they couldn’t slip through the net later. There was nothing wrong with what had been done, but the way it was recorded didn’t highlight those items due later.
Nobody is perfect
At the time of this incident, I felt like the guy looking back at me in the mirror was a genuine real-deal idiot.
Now, I know that nobody is immune to human error.
Have I seen this sort of thing before? Yes. So many times, I’ve lost count – it just hadn’t involved me before.
Learn from my story, double-check your own work, but also check the work of people who you think wouldn’t make a mistake.
We’re all more than capable of getting it wrong.
Footnote
Photo: CAA