Narrative:

[We had a] two engine fire switch lights illuminated in cruise at FL400. Ran the memory items; then the check list and advised ATC we needed the closest airport. ZZZ was decided. Two aircraft flying close advised there was no indication of fire or flames. A company aircraft advised they would contact company for us advising them of our intentions. We declared an emergency and asked for the trucks. I continued to fly and the other captain ran the checklists. We landed on runway 31 without incident. The firemen inspected the aircraft. We deplaned and worked on a recovery flight for our passengers.

Related reports:

Google
 

Original NASA ASRS Text

Title: A CE560XL flight crew declared and emergency and diverted to the nearest suitable airport upon receipt of fire warnings for both engines. Upon landing determined the warnings were apparently invalid.

Narrative: [We had a] two engine fire switch lights illuminated in cruise at FL400. Ran the memory items; then the check list and advised ATC we needed the closest airport. ZZZ was decided. Two aircraft flying close advised there was no indication of fire or flames. A company aircraft advised they would contact company for us advising them of our intentions. We declared an emergency and asked for the trucks. I continued to fly and the other Captain ran the checklists. We landed on Runway 31 without incident. The firemen inspected the aircraft. We deplaned and worked on a recovery flight for our passengers.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.