FILE PHOTO: Aengus Kelly, CEO and Executive Director of AerCap, speaks at the 2016 International Air Transport Association (IATA) Annual General Meeting (AGM) and World Air Transport Summit in Dublin, Ireland June 1, 2016. REUTERS/Clodagh Kilcoyne

DUBLIN (Reuters) - Owners of Boeing's BA.N grounded 737 MAX jet must keep cool heads and avoid offering panic discounts on sale or lease prices to avoid undermining its long-term value, the head of one of the world's largest aircraft lessors Aercap AER.N said on Monday.

"Discipline and keeping a cool head is vital because if people panic and lease the airplane or sell the airplane at knock-down rates for an extended period of time, it will be harder for the residual value of that asset to recover," Aercap's AER.N Aengus Kelly told the Airline Economics aviation finance conference in Dublin.

Aercap has 100 Boeing 737 MAX jets on order.

“The brand is not in a great place right now and what we need to do is recover that brand operationally and then ... be absolutely disciplined when it comes to placing the aircraft,” Kelly said.

(This story has been refiled to fix typographical error in headline)