SiteIt's the second Monday in August. The flat sorter has stopped on a fault code nobody on shift has seen before. There's one engineer on site who really knows that machine. They're on a sunbed in Spain, and they've been on holiday for exactly one day.
Someone suggests ringing them. Someone else says you can't. The shift manager rings anyway, and gets voicemail.
You'll know the machine. Every site has one. Old, a bit custom, modified over the years by the same person, with half the know-how in their head and the rest in a notebook in their locker.
What goes wrong here is planning, not the fault. Nobody planned for the one person being away, even though the holiday was booked in March.
Don't ring them on the beach
The temptation is to call them anyway. Sometimes they'll pick up and talk you through it. Most engineers would.
We'd avoid it. Annual leave is a legal right. Almost all workers get 5.6 weeks* of paid holiday a year (GOV.UK). A fortnight away is part of what keeps your best engineer working for you. Ring them every time the sorter coughs and they'll stop going away, or stop working for you.
There's a practical problem too. Fault-finding by phone, from memory, with someone who can't see the HMI, is slow. You might get lucky. You'll more likely lose two hours and still be stuck.
If you have to call, agree it with them before they go. One named person rings, only for a set list of machines, and only after the shift has tried the steps they left. That's a fair deal, made in advance. Calling them without that agreement is a favour you're spending.
Get through today
So the sorter is down and the one engineer is away. Here's the order we'd work in.
Start with what they left behind. Check the locker notebook, the shared drive and the CMMS history for that machine. Look for the last time this fault code came up. A short note like "reset the encoder on the induct" can save a morning.
Then check the backups. If the fault looks like a program or parameter problem, you need the latest PLC and drive backups, and you need to know they're the latest. Our post on PLC program backups covers what you'll wish you had.
Work the fault properly, without guessing. Even without a manual, drive fault codes and PLC inputs can be read. Our post on reading drive fault codes when the manual's gone sets out an order to work in.
Then make the call early. If the shift isn't getting closer after half an hour, bring in help. That could be the machine maker or an outside engineer who knows that type of kit. Send them the make, model, fault code, what's been tried and photos of the HMI before they set off.
Watch for the shortcut. With the expert away, people try things they wouldn't try with the expert stood there. Bridging out a sensor. Changing a drive parameter to "see what happens". HSE's code of practice for PUWER expects maintenance to be done "by people who are competent to do the work" (L22, paragraph 79). Where a machine carries specific risks, PUWER limits repairs to people "specifically designated" for that work, who have had adequate training for it (regulation 7). Being the only one on shift doesn't make someone competent on that machine.
The real fix is before the holiday
Holidays aren't a surprise. Most are booked weeks or months ahead. That gives you time.
Start by finding your one-name machines. List every machine on site and write next to it who can fix it on their own. Any machine with one name is a risk every time that person is off. Our post on a skills matrix for your maintenance team shows a simple way to set it out. And if that machine is one that can stop the whole site, it goes to the top of the list. We covered how to spot those in single points of failure.
Get the know-how out of their head. Before the holiday, give your expert a few paid hours to write down what they know. Not a full manual. One page per machine:
- the faults that come up most, and what usually fixes them
- the settings that matter, and where they're kept
- the modifications made over the years, and why
- the parts that wear, and where the spares are
- who to call outside, and their numbers
Keep it with the machine and on the shared drive. PUWER requires that people who use work equipment, and those who supervise them, have "adequate health and safety information and, where appropriate, written instructions" for it (regulation 8). A one-page sheet won't cover all of that, but it's a start you can build on.
Pair someone up. Over the next few months, put a second engineer with the expert on every planned job on that machine. Let the second person do the work while the expert watches. It's slower at first. It's a lot cheaper than a stopped sorter.
Plan the leave around the risk. You can plan holiday cover without blocking anyone's leave. If two people both know the machine, try not to have them off in the same fortnight. An employer can refuse a leave request with notice of at least as many days as the leave asked for, plus one day* (GOV.UK). That's a last resort. It's far better to plan the rota early, so nobody gets told no. Our post on next summer's holiday rota covers that.
Line up outside cover for the fortnight
Then there's the gap you can't close in time. The second engineer isn't ready yet, and the holiday starts on Saturday.
For that fortnight, line up an outside engineer who knows that kind of machine. Make sure they're actually on call for those dates, with a number that gets answered. Better still, get them on site for a shift before the holiday so they see the machine running. Walk them round it with your expert. Show them the isolation points, the HMI, the panel and the notebook. Our post on inducting a contract engineer sets out what to show them.
Count what that costs against one lost day on the machine. For most sites, one stopped shift on the sorter in peak costs more than a fortnight of cover.
What to do on Monday
- List every machine on site that only one person can fix on their own.
- Check the holiday chart for when each of those people is next off.
- Book a few paid hours for each of them to write a one-page sheet before they go.
- For any gap you can't close in time, line up an outside engineer who knows that kit.
* Holiday entitlement and notice periods correct as of 19 September 2026. Check GOV.UK's holiday entitlement pages for the latest. Paragraph numbers refer to L22, fourth edition (2014, amended 2018).