It was one of the biggest crises in the airport's history, leading to 1,000 cancelled flights and disruption for 140,000 passengers, as a drone sighting caused Gatwick to shut down for 36 hours. The financial cost was substantial - closure for just one day costs around £50m.
The incident, which began on 19 December, was also a huge challenge for the 12-strong in-house comms team (agency help was limited to drafting a statement from the CEO), making front-page news for three consecutive days.
Griffiths posed the question of whether it's ever possible to be ready for such a crisis.
"I think unfortunately the answer is 'yes' and 'no'," she told the Crisis Communications conference.
"There are definitely some things you can do to help yourself and make things easier. But you've got to have the mentality that you're not going to know everything in advance of a crisis."
There was "no plan on drones", for example. "This wasn't something I had a library of. We had to think in the moment.
"What we did have is a really strong, clearly defined crisis process at the airport itself and also within our team about what our roles and responsibilities were."
PRWeeks outline some crisis comms lessons from the incident below:
Get the first 30 minutes right
For Griffiths, the first thing is to get your facts straight - ask yourself what you know for sure. "There's a ridiculous amount of data and information you could share, but it's coming from all different sources, it's hard to verify. Everyone is trying to fix the problem of the drone on the runway; they don't care about your 20 questions about data."
The second is to prioritise digital channels, in this case, using Twitter as the first point of communication.
"It's [about] passengers first, then we start working on our media statements. I would also be putting a call into our key stakeholders to let them know something's going on, [saying] 'please be out there and sharing any lines'."
We’re very much a #Twitter first organisation - before the press statement, media interviews, everything else. It’s passengers first. Let them know in first 30 mins that you’re aware of situation and will keep them updated: Heather Griffiths @Gatwick_Airport #prwcrisis #drones pic.twitter.com/D3kYmoDpdn— Jemima Gibbons ?? (@JemimaG) June 26, 2019
Coordinate with stakeholders
The incident involved many other stakeholders, including airlines, government organisations, and police and security services.
"Making sure you have a role in your team clearly dedicated to keeping those people updated, and for them to feed you information so you can quickly know what to expect... is really essential for us," said Griffiths.
"I think in [the drones incident] that worked really well because it meant we were able to know all the things they were going to say, know if they said something they shouldn't have - which is really important as well - and know what Chris Grayling, the transport minister, was going to come out and do and when he was going to do it. That was really important for us to help manage our response."
She makes another crucial point: "We don't have the view at Gatwick that we should throw our partners under the bus. I don't think it particularly benefits anyone.
"We very much had a sense of the media wanting to play out that narrative and getting us to talk about how ‘the Government weren’t doing enough or the police didn’t do a good job’?"
Go in early
There was a debate about whether to co-ordinate media interviews from the very early part of the crisis unfolding. "When do you go, because it could all be over in an hour and you all look a bit silly. But we felt that the fact the press had come straight down to the airport... we should get in front of it and give them a spokesperson at that point and use the media to get messages to passengers.
"I think the media really appreciated that," she added. "We were honest and upfront. We didn't have all the answers, we couldn't tell them who was flying the drone around - we still can't. But I think they appreciate the fact we made the effort to speak to them early on.
"We also actively encouraged other stakeholders to speak early, and not be scared by the fact they didn't have all the information." (Below is Gatwick chief operating officer Chris Woodroofe in one of his many media interviews)
Work on media logistics
Griffiths said one person was on hand to manage all the requests for interviews, saying it can get "really messy" co-ordinating responses in such a time. "It's the sort of thing that can trip you up when you're really busy."
Having someone looking after the 'press pen' - located just outside the main terminal - also proved beneficial. "Using them as a bit of a sense check on things, and asking them what they were hearing, was really useful for us to inform our decision-making".
A WhatsApp group was set up for the media in the press pen to update them on, for example, new statements or announcements from other stakeholders. "That sense of knowing we were thinking about [the journalists], knowing we were thinking about their timelines, meant there was empathy."
Media were directed to the press pen initially, away from passengers, to "stop them roaming around, which you can only do to a certain extent".
They later started to take broadcast media into the terminal. "After 20 hours they're going to get fed up and go into the terminal anyway, so you might as well try and manage it," Griffiths said. It also gave an opportunity to show how the terminal is beginning to be "under control and managed".
"Just think about the story visually, as well as your corporate position," she advised.
Watch internal comms
Griffiths also stressed the importance of internal comms professionals making sure those airport staff who were talking to passengers knew what kind of messages to put across.
Be wary of staff burnout
While it may be tempting to have the entire comms team involved from the beginning of a crisis, Griffiths emphasised the need to hold some back.
In the past, the whole team has gone straight to the airport as soon as the crisis began. "As we know, 12 hours later, everyone's still at their desks, everyone's completely burnt out and it's a bit of a car crash. We made sure we held people back and someone had a rota of shifts." The team also made sure rooms were available at the airport's hotels. "That just helps sustain us a little bit."
Griffiths added: "The wellbeing of your team is so important, especially during a crisis that goes on for a long time. Simply asking people how they're doing during a crisis, making sure someone is going to get the sandwiches the coffees and the water..."
The approach applies post-crisis, too. Griffiths said it was important to ask comms staff how they felt, what could have been improved, if it made them feel uncomfortable - and even which parts they enjoyed.
Work out all potential stakeholder contacts
Griffiths said working with new stakeholders in the drone crisis was "a challenge for us". "I never had any contact with the MoD (Ministry of Defence)," she said, and urged comms professionals to think about who beyond their normal contacts may need to be engaged in a crisis. "If we'd known who to contact in the press teams, it would have been so helpful."
'You can't do everything'
Griffiths said: "You get to the stage where media calls go unanswered, or people need to take time out to have a briefing so they're aware of the latest information, and other stuff doesn't get done in those 10 minutes. So be it. You can't do everything."
Expect the unexpected
News stories identifying the alleged perpetrators, later released by police without charge, made front-page news on several newspapers.
"This could have been all-consuming for our team," said Griffiths. "We were getting so many calls about it. If you're ever doing crisis simulations, what is that leftfield grenade that could be thrown at you and be really destructive and how do you mange that?"
She said Gatwick had terrorism training with the unexpected twist that the terrorist is an employee of the airport.
Careful with post-crisis tone
In a case of unfortunate timing, the £2.9bn sale of Gatwick to Vinci SA was announced two days after the drone crisis hit. The narrative around the sale was "toned down", Griffiths said, with some communications rewritten with the drone incident in mind.
Messages were toned down more generally in the period after the drone. "We felt it was really inappropriate to bang on about how people can get a great offer in our shops at the airport when 140,000 people had their journeys ruined."
There was a "slow ramp up of messages" in January for a new 15-year plan for the airport. The "tonnes" of interview requests about the drone attack were turned down, however. "We refused everything on the basis that we were assessing all the information from all the different sources. I think people were fairly understanding for a while."
BBC News and Panorama were given access in March, "because we felt they were going to go ahead anyway, so why not get your voice out there and get an accurate story into those news pieces?"
There was also a desire to move the debate "away from Gatwick and into the wider question around drone management, security at airports and infrastructure, and push the narrative that way".