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An A320 experiences a temporary loss of aircraft control from wake turbulence when climbing to the same flight level as a B747 10 mi ahead. WX was mostly clear and there was no evidence of a condensation trail. Reporter had asked for climb to avoid clouds since their engine anti-ice was inoperative.
| Attributes | |
| ACN | 412503 |
| Time | |
| Date | 199808 |
| Day | Sat |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | atc facility : yyj |
| State Reference | BC |
| Altitude | msl bound lower : 28700 msl bound upper : 29000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zse |
| Operator | common carrier : air carrier |
| Make Model Name | A320 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other Other |
| Flight Phase | climbout : intermediate altitude cruise other |
| Route In Use | enroute airway : j589 |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | common carrier : air carrier |
| Make Model Name | B747 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 80 flight time total : 12000 flight time type : 20 |
| ASRS Report | 412503 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : instrument pilot : commercial |
| Events | |
| Anomaly | aircraft equipment problem : less severe inflight encounter other other anomaly |
| Independent Detector | other flight crewa |
| Resolutory Action | controller : issued new clearance flight crew : regained aircraft control flight crew : exited adverse environment |
| Consequence | Other |
| Supplementary | |
| Air Traffic Incident | other |
Narrative:
Dispatched with engine anti-ice inoperative due to bleed valve lock-out. Also limited to FL310. Destination and en route forecasts ok for this flight. Initial climb to FL270 due to B747 at FL290. Clouds encountered abeam sea VORTAC requiring anti-ice. Climbed to FL290, B747 10 NM ahead. Upon reaching FL290, encountered light chop associated with jet wash then a rapid right 30 degree bank followed by left 30 degree bank. Autoplt disengaged and unusual attitude recovery procedure used to regain aircraft control. Immediate descent to FL270 initiated. Wake turbulence stopped at FL287. Cruise winds 280 degrees at 10 kits. ATC controllers informed. No crew members nor passenger injured. Never before experienced wake turbulence at cruise altitude and at 10 NM spacing. Callback conversation with reporter revealed the following information: the PIC, PF, was surprised at this unexpected encounter. He had always exercised caution when behind B747-757 type aircraft during approach and landing but had never had this occur at the higher altitudes. He had not thought of asking for an offset to the upwind side of the B747 but will in the future. A TA was not given and it appeared to the reporter that ATC did not expect that there would be any wake turbulence in that area of climb. Reporter felt that ATC should be more educated in those procedures that would assist flcs to avoid problematic vortex areas.
Original NASA ASRS Text
Title: AN A320 EXPERIENCES A TEMPORARY LOSS OF ACFT CTL FROM WAKE TURB WHEN CLBING TO THE SAME FLT LEVEL AS A B747 10 MI AHEAD. WX WAS MOSTLY CLR AND THERE WAS NO EVIDENCE OF A CONDENSATION TRAIL. RPTR HAD ASKED FOR CLB TO AVOID CLOUDS SINCE THEIR ENG ANTI-ICE WAS INOP.
Narrative: DISPATCHED WITH ENG ANTI-ICE INOP DUE TO BLEED VALVE LOCK-OUT. ALSO LIMITED TO FL310. DEST AND ENRTE FORECASTS OK FOR THIS FLT. INITIAL CLB TO FL270 DUE TO B747 AT FL290. CLOUDS ENCOUNTERED ABEAM SEA VORTAC REQUIRING ANTI-ICE. CLBED TO FL290, B747 10 NM AHEAD. UPON REACHING FL290, ENCOUNTERED LIGHT CHOP ASSOCIATED WITH JET WASH THEN A RAPID R 30 DEG BANK FOLLOWED BY L 30 DEG BANK. AUTOPLT DISENGAGED AND UNUSUAL ATTITUDE RECOVERY PROC USED TO REGAIN ACFT CTL. IMMEDIATE DSCNT TO FL270 INITIATED. WAKE TURB STOPPED AT FL287. CRUISE WINDS 280 DEGS AT 10 KITS. ATC CTLRS INFORMED. NO CREW MEMBERS NOR PAX INJURED. NEVER BEFORE EXPERIENCED WAKE TURB AT CRUISE ALT AND AT 10 NM SPACING. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE PIC, PF, WAS SURPRISED AT THIS UNEXPECTED ENCOUNTER. HE HAD ALWAYS EXERCISED CAUTION WHEN BEHIND B747-757 TYPE ACFT DURING APCH AND LNDG BUT HAD NEVER HAD THIS OCCUR AT THE HIGHER ALTS. HE HAD NOT THOUGHT OF ASKING FOR AN OFFSET TO THE UPWIND SIDE OF THE B747 BUT WILL IN THE FUTURE. A TA WAS NOT GIVEN AND IT APPEARED TO THE RPTR THAT ATC DID NOT EXPECT THAT THERE WOULD BE ANY WAKE TURB IN THAT AREA OF CLB. RPTR FELT THAT ATC SHOULD BE MORE EDUCATED IN THOSE PROCS THAT WOULD ASSIST FLCS TO AVOID PROBLEMATIC VORTEX AREAS.
Data retrieved from NASA's ASRS site as of July 2007 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.