AirAsia Caterham's incident packed start to its debut Moto2 season continued at Austin, when both riders took down other competitors within the opening two laps.

Riders Johann Zarco and Josh Herrin had previously been brought down in an incident on the first lap at the Qatar season-opener, Zarco remounting to finish 23rd.

Hopes of a fresh start in Texas then ended at the first turn, when home rookie Herrin caused a multi-rider pile-up.

"Going into turn one I made a dumb mistake; I didn't really think about my position on the track and was way too far on the inside. It's something that shouldn't happen and I'm just sorry to the guys that I hit," said the American Superbike champion.

Herrin rejoined the race but later fell for a second and final time.

"I managed to remount and tried as hard as I could to get back up towards the front as much as I could. I started to get into a rhythm and managed to get up to P21 but I was just pushing too much and ended up tucking the front.

"I'm really disappointed as I felt like in the race I could have made something happen. I need to try and get a better grid position. This time it's nobody's fault but mine and I'm so sorry for my team who all worked incredibly hard."

Team-mate Zarco looked set for a podium challenge after leading Friday practice and qualifying second on the grid.

But it counted for nothing when he took both himself and Julian Simon down with a mistimed pass on lap two of the race. Unlike in Qatar, Zarco was not able to continue.

"With these very slow corners there is always some confusion and that's why on the first corner I lost many positions, but this wasn't a big problem because then I was quite comfortable to overtake riders," said the Frenchman.

"Then in one braking point I tried to overtake one rider and I saw that I was already on the limit. I tried to save it my movement cutting the line but then I touched Simon and that was really bad.

"After such a good weekend it's so disappointing; I made a mistake and I'm really sorry to the team."

Team manager and former grand prix rider Johan Stigefelt stated: "We worked so hard all over the weekend and especially for Johann, I was looking forward to this race because I knew he could fight for the podium positions today.

"Josh crashed on the first lap and I think he just needs to take it step by step and start learning how this championship works. Starting from Friday at Argentina will begin with a new strategy for him and see if that works better."

The 'Caterham Suter' machines feature a Suter chassis with aerodynamic changes inspired by Caterham's F1 experience.