The Hyundai pairing were sitting in fourth head into stage five, the final test of Friday morning’s loop, when drama struck.
Lappi ploughed into trees lining the gravel road after misjudging a right-hander. The impact caused significant damage to the i20 N and it is unlikely the car can be repaired to return on Saturday.
Both driver and co-driver emerged from the crash relatively unscathed. Lappi suffered a swollen ankle in the crash, while co-driver Ferm was transferred to hospital for a precautionary X-ray on his ribs.
Asked about the frustration of retiring from his home WRC round, 2017 Finland winner Lappi said: “Okay, over here it feels bad [to retire] but the first sentence from my mouth when I saw Janne was that ‘it is good that we are alive’ because it was really scary when I saw the trees.
“I’m okay. My ankle is swollen a bit, but it is not broken. Janne is now in hospital having an X-ray for his ribs, no drama, just for precaution.”
Lappi explained that an optimistic pacenote had caused the error that led to the crash and confirmed that the wet conditions were not a factor in the incident.
“It was just a pacenote error, [it was] too optimistic for the right-hander. The angle was wrong,” he added.
“On the left before, I lost the rear a little bit so I didn’t really have a good line in terms of that. But I had no chance to do the right, so we went straight out.”
Lappi had been struggling to match the pace of the Toyotas prior to the crash and had no answers for the pace deficit.
“I felt comfortable but the speed was not what I wanted,” he said. “It felt we were doing everything right and we were close to the limit.
“On the first stages I tried to be smart and not push too much and the times were not there. In stage four, I pushed really hard and I had some moments there and still the time was not really there.
“The Toyotas were just too fast. I didn’t come here to fight for the third position. I have no answers I thought we were at a good level but it seems like we are behind.”
Lappi was one of four Rally1 retirements on Friday after M-Sport duo Ott Tanak and Pierre-Louis Loubet exited the rally on stage three, before Toyota's Kalle Rovanpera rolled out of the lead on stage eight.