Narrative:

Had been cruising at FL370 and was issued a descent to FL290. While in descent at mach .77 and around 31;000 feet; experienced significant wake turbulence roll (approximately 45 degrees aob along with aircraft 'roll authority' warning) due to boeing 767 aircraft 8-10 miles ahead of us. I contacted ATC and told them that we needed more separation and they allowed us to slow. When I had the chance; I made announcement to passengers explaining that it was unexpected and isolated wake turbulence that should not happen again. Later near 10;000 feet; I started to get into wake turbulence again; so I queried ATC as to was it same aircraft and stated we needed more separation. Boston approach stated that they had just implemented new reduced separation criteria for B-767 aircraft which were now considered a lower category heavy aircraft (I believe 're-certified as class C' was terminology used or something close to that). Not sure what the ATC separation standard was at altitude; but I am very thankful we were already descending or it likely would have been an emergency descent. Down low with approach control; the new 3.5 miles of separation minimum behind 'heavy; low and slow' B-767 (previously was 5 mile minimum per my query to controller) was not sufficient. The FAA should further address safety issues associated with reduced wake turbulence separation. Been flying close to [xx] years and this was an eye opener at altitude.

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Original NASA ASRS Text

Title: Air carrier Captain reported encountering wake turbulence descending into BOS in trail of a heavy B767; and expressed concern about an apparent recent change to ATC procedures allowing reduced separation to heavy B767 aircraft.

Narrative: Had been cruising at FL370 and was issued a descent to FL290. While in descent at Mach .77 and around 31;000 feet; experienced significant wake turbulence roll (approximately 45 degrees AOB along with aircraft 'roll authority' warning) due to Boeing 767 aircraft 8-10 miles ahead of us. I contacted ATC and told them that we needed more separation and they allowed us to slow. When I had the chance; I made announcement to passengers explaining that it was unexpected and isolated wake turbulence that should not happen again. Later near 10;000 feet; I started to get into wake turbulence again; so I queried ATC as to was it same aircraft and stated we needed more separation. Boston Approach stated that they had just implemented new reduced separation criteria for B-767 aircraft which were now considered a lower category heavy aircraft (I believe 'Re-certified as Class C' was terminology used or something close to that). Not sure what the ATC separation standard was at altitude; but I am very thankful we were already descending or it likely would have been an emergency descent. Down low with approach control; the new 3.5 miles of separation minimum behind 'heavy; low and slow' B-767 (previously was 5 mile minimum per my query to Controller) was not sufficient. The FAA should further address safety issues associated with reduced wake turbulence separation. Been flying close to [XX] years and this was an eye opener at altitude.

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.