Narrative:

Our falcon 2000EX easy encountered what appeared to be severe wake turbulence while approaching los angeles international airport (lax).after an uneventful climb; we settled into normal cruise at FL350 and mach 0.82. Eventually; ATC instructed us to maintain mach 0.79. We were subsequently cleared to descend via the IRNMN2 arrival; and were advised to maintain a transition speed of 270 KIAS. We used the VNAV feature of our primus epic easy autoflight system to accomplish the descent and adhere to the published crossing restrictions; and the system performed flawlessly. As we descended through FL260; the airplane began a roll to the right. The pilot flying (PF) disconnected the autopilot and counteracted the roll with aileron input; which he indicated [it] offered considerable resistance. As the wings leveled; the aircraft snapped abruptly to the left; resulting in a bank angle of approximately 30 degrees. The PF again applied aileron pressure to counteract the roll; and eventually leveled the wings. The entire event lasted only a few seconds. After ascertaining that the encounter had ended; the PF stabilized the aircraft and re-engaged the autopilot. I immediately advised los angeles center of our severe turbulence encounter; and the controller inquired whether we believed it was wake turbulence. After a brief discussion with the PF; we concluded that it did in fact appear to be wake turbulence; and I indicated our belief to the controller. He advised us that there was a boeing 777 ahead of us. We then identified the subject aircraft on our TCAS system; which appeared to be about 10 nautical miles ahead of us; and over 4;000 feet below us.the controller inquired whether anyone was injured. Thankfully; our passengers were both seated with their seat belts fastened; and neither they nor the aircraft sustained any injury.to mitigate the chances of another encounter during the remainder of the arrival; we decided to re-program the FMS to cross 'at' the highest allowable altitudes at the remaining fixes; which might help keep us above the boeing's flight path. No further wake turbulence was encountered; and we landed uneventfully.later in the day; I initiated a phone conversation with los angeles center about the incident. The center operations manager reviewed the radar data; and advised me that the boeing was initially at FL370 (2;000 feet above our cruise altitude) and was vectored across our flight path 14.1nm ahead of us while descending. He also advised me that the minimum required separation was 10nm; but that he had personally heard of wake turbulence encounters occurring with up to 20nm of separation. He filed a report on the incident; and advised us to submit a report as well.in retrospect; neither the PF nor myself could have possibly foreseen; nor taken any action to prevent; this incident. Our humble recommendation would be to increase the required separation of lighter aircraft behind heavy jets from 10nm to at least 20nm.

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Original NASA ASRS Text

Title: Falcon 2000 First Officer reported encountering 'severe' wake turbulence approaching LAX at FL260 14 miles in trail of a B777.

Narrative: Our Falcon 2000EX EASy encountered what appeared to be severe wake turbulence while approaching Los Angeles International Airport (LAX).After an uneventful climb; we settled into normal cruise at FL350 and Mach 0.82. Eventually; ATC instructed us to maintain Mach 0.79. We were subsequently cleared to descend via the IRNMN2 Arrival; and were advised to maintain a transition speed of 270 KIAS. We used the VNAV feature of our Primus Epic EASy autoflight system to accomplish the descent and adhere to the published crossing restrictions; and the system performed flawlessly. As we descended through FL260; the airplane began a roll to the right. The Pilot Flying (PF) disconnected the autopilot and counteracted the roll with aileron input; which he indicated [it] offered considerable resistance. As the wings leveled; the aircraft snapped abruptly to the left; resulting in a bank angle of approximately 30 degrees. The PF again applied aileron pressure to counteract the roll; and eventually leveled the wings. The entire event lasted only a few seconds. After ascertaining that the encounter had ended; the PF stabilized the aircraft and re-engaged the autopilot. I immediately advised Los Angeles Center of our severe turbulence encounter; and the Controller inquired whether we believed it was wake turbulence. After a brief discussion with the PF; we concluded that it did in fact appear to be wake turbulence; and I indicated our belief to the Controller. He advised us that there was a Boeing 777 ahead of us. We then identified the subject aircraft on our TCAS system; which appeared to be about 10 nautical miles ahead of us; and over 4;000 feet below us.The Controller inquired whether anyone was injured. Thankfully; our passengers were both seated with their seat belts fastened; and neither they nor the aircraft sustained any injury.To mitigate the chances of another encounter during the remainder of the arrival; we decided to re-program the FMS to cross 'at' the highest allowable altitudes at the remaining fixes; which might help keep us above the Boeing's flight path. No further wake turbulence was encountered; and we landed uneventfully.Later in the day; I initiated a phone conversation with Los Angeles Center about the incident. The Center Operations Manager reviewed the radar data; and advised me that the Boeing was initially at FL370 (2;000 feet above our cruise altitude) and was vectored across our flight path 14.1nm ahead of us while descending. He also advised me that the minimum required separation was 10nm; but that he had personally heard of wake turbulence encounters occurring with up to 20nm of separation. He filed a report on the incident; and advised us to submit a report as well.In retrospect; neither the PF nor myself could have possibly foreseen; nor taken any action to prevent; this incident. Our humble recommendation would be to increase the required separation of lighter aircraft behind heavy jets from 10nm to at least 20nm.

Data retrieved from NASA's ASRS site 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.