7.30 pm at Zurich Airport: the large SWISS hangar is still empty. Only the markings on the floor indicate where aircraft will be parked a few hours later. Meanwhile, preparations for the night are under way in the offices adjoining the hangar. One after another, employees arrive. The language spoken is mostly English, coloured by accents from across Europe. 

In the middle of it all is Stephan Allenspach. The 48-year-old has spent his entire career in aviation. “I completed my apprenticeship as a aircraft mechanik with Swissair 33 years ago,” he says.

Today, Stephan works as Head of Production Management in aircraft maintenance at SWISS. He has also been working night shifts for the past 16 years. This means five days working from 7.30 pm until 5.30 am, followed by five days off before the next block of night shifts begins. 

On this Thursday evening, we find ourselves halfway through one of these rotations. Stephan and his colleagues are sitting in the office discussing the upcoming night. “By 9.30 pm, the mechanics will have arrived. By then, the planning for the night has to be finalised.” 

8.00 pm: Planning the night ahead 

The schedule includes every aircraft requiring work from the mechanics. On one aircraft, for example, the emergency slide needs to be replaced. Not because it has been deployed, but for safety reasons. Every component inside an aircraft has a different service life. Once the manufacturer’s specified limit has been reached, the part is replaced. Another aircraft needs to be cleaned and disinfected, while a third requires a new coffee machine on board. 

“On average, our mechanics work on between one and three aircraft per night shift,” Stephan explains. But before work can begin in the hangar, the planning has to be completed. That is why, at 8.00 pm, the Head of Production Management heads to the Short Term Planning department. The team prepares the shift schedule for all aircraft making a technical stop in Zurich. Different priorities are assigned, as not every task has to be completed within the next 24 hours. “Safety is always our main focus,” says Stephan. Shortly after the meeting with Short Term Planning, the next briefing with the mechanics’ management team is already under way. 

Among the topics discussed is which aircraft will be worked on inside the hangar and which will remain outside. “There is a great deal of strategy behind these decisions as well,” explains Allenspach. Depending on aircraft size, a full hangar can accommodate between four and nine aircraft. Aircraft returning to operation in the early morning hours must not be blocked by others that will remain in the hangar throughout the day. 

“During the night shift, it sometimes happens that an aircraft lands in Zurich at 11.00 pm and is scheduled to depart again early the next morning.” This naturally creates a level of prioritisation for the mechanics, but once again, safety always comes first. If the required work cannot be completed during the night shift, the aircraft will not be released back into service. 

But who decides on maintenance intervals? “There are different ways this is determined. As standard procedure, all of our aircraft undergo regular inspections. In addition, aircraft manufacturers provide specifications indicating when a component has to be inspected, maintained or replaced.” Added to this are the regular reports, known as ‘incomings’, submitted by the cockpit and cabin crew. “We also have what are known as ‘findings’ from our mechanics. These are issues they notice during their inspections.” 

9.30 pm: The mechanics take over 

Shortly before 9.30 pm, the plan for the night shift is finalised. The mechanics are waiting in the large break room. Each night shift, 60 employees work for SWISS, alternating in two groups. The atmosphere among them is relaxed, with jokes and laughter filling the room. But as soon as the briefing for the night shift begins, everyone is fully focused. 

The mechanics are informed which aircraft they will be working on, in which positions and what their tasks are. They also receive this overview in the form of a worksheet. “That way, everyone also knows what the person next to them is working on.” 

After the meeting, the hangar gradually comes to life. The large doors leading to the apron open and the mechanics collect the required materials, tools and procedural documentation. These have already been prepared in boxes beforehand, a step that speeds up the workflow and provides an additional layer of control. 

One after another, the aircraft are towed into the hangar. The majestic machines stand atop small aircraft tugs, guided into position by the employees on the ground. 

“During the night shift, there are no distractions and productivity is high,” says Stephan. At the same time, he acknowledges that this working model is not suitable for everyone. “Your body has to adapt to the rhythm.” Five nights on, five days off. It is also a model that can appeal to people living abroad. “Whenever we advertise vacancies, we receive applications from across Europe.” 

11.00 pm: Voices from the night shift 

One person who has been commuting between countries for SWISS for the past 20 years is Jean. He says he has always been fascinated by aviation. “Thanks to my working hours, dealing with traffic is much easier for me.” A colleague who has also worked for SWISS for many years agrees: “When I travel to work by public transport in the evening, the trains are empty.” Another advantage, he says, is the five days off. 

At the same time, night work comes with a great deal of responsibility, the mechanic continues. “In our job, we always have to be confident in our work and able to assess ourselves properly.” However, he says the system is well designed, with double inspections and additional safety procedures in place. 

Mechanic Sergio particularly values this responsibility. “The aircraft arriving here during the night often have to depart again the following morning. That means my colleagues and I can take care of the entire handling process from A to Z.” Knowing that he is part of a system responsible for passenger safety motivates him. “Many people fly with us every day. What I do here has to be precise.” 

Sergio has been with SWISS since his apprenticeship. After qualifying six years ago, he moved to the night shift. The reversed routine does not bother him. “While I’m working, I usually do not even notice that it’s night-time. I’m so focused that I do not get tired.” 

Nor is there any sign of tiredness among the other mechanics. Despite the highly concentrated work on the large aircraft, there is still time in between for a joke and a quick laugh. 

1.00 am: A one-hour break during the night 

Before the team takes a one-hour break sometime between 1.00 am and 3.00 am, another meeting takes place to assess the progress of the work. An important briefing for Stephan Allenspach and his team follows at 4.30 am with the operational department. One by one, the aircraft leave the hangar again, only to return to service a short time later. 

7.30 am: When Zurich wakes up 

At 7.30 am, as the city begins to wake, the mechanics’ night shift comes to an end. The large hangar stands empty again, albeit only briefly before the day shift takes over. Stephan Allenspach also finishes his work. Within a few hours, the aircraft will once again be taking to the skies. Stephan describes the feeling of standing in the empty hangar after many hours of work as “magical”. Asked whether that sense of magic has faded after decades in aviation, Stephan replies with a smile: “Never.”