Narrative:

At the time of the incident; I had just completed a climb to approximately 10500 ft MSL and was exiting the thermal. I observed the approaching jet already close to me and near/at my altitude. Wings level; it was on course to pass just east of my position. My heading was already wbound exiting the thermal. I accelerated (dove) to maximize separation and minimize the risk of wake turbulence. Traffic is a regular characteristic of this area and surveillance/avoidance is thus a priority. Normally; a thermal inversion caps hang glider operations at approximately 5000 ft MSL. Under these conditions; chief concerns are from descending; sbound traffic: commercial aircraft; inbound to bur airport; descending across the ridgeline at 4000-5000 ft approximately 2 NM east of the incident location; and GA aircraft; inbound to whiteman; bur and vny airports; descending through the pacoima dam pass at 2500-4500 ft approximately 4 NM ese of the incident location. Scan attention; although spread up/down and in all directions; can be prioritized upon these familiar traffic patterns. Descending traffic is comparatively easy to spot against a backgnd of sky; rather than ground. And; both commercial and GA pilots are aware of hang glider operations in the area and heighten their own scans; as well. However; the day's unusual WX conditions changed this typical balance of traffic concerns. Absent an inversion; thermal climbs to more than 10000 ft MSL were possible. These climbs added a different traffic mix; including GA operations through/above the newhall pass; jet traffic climbing out of van nuys; and cruise traffic along V165. Attention had to be spread among climbing; descending; and cruise traffic on all headings. Having left lift; I was descending. The jet was thus initially below me and difficult to detect against the urban backgnd to the south of my position. Despite heightened awareness; I did not spot it until it was already close to my position. And I would suspect that the jet's pilot may not have been expecting hang glider traffic at +10000 ft. Evasive action was possible and was taken. However; the goal must be to reduce the risk of a similar close encounter in the future. The simple and obvious answer is that I must and shall continue to improve my traffic scan skills; especially in terms of detecting climbing (or slightly-lower-altitude) traffic against an urban/terrain backgnd. However; I also plan to investigate the feasibility of mounting a portable collision alert device and/or a transponder on my hang glider. Such a device would be especially useful on days when WX conditions permit operations to higher-than-normal altitudes and further away from our normal practice area. Callback conversation with reporter revealed the following information: the reporter stated that this location is popular for hang gliding activity. A launch sight is nearby; and a suitable landing area is available. The altitude attained in this report was unusual. When conditions prevail to allow higher altitudes to be achieved; an attempt is normally made with the local FSS to issue a NOTAM. Such was not the case in this instance.

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Original NASA ASRS Text

Title: HANG GLIDER PLT WAS INVOLVED IN NMAC WITH A CORPORATE JET WHILE GLIDING ABOVE 10000 FT IN THE LOS ANGELES BASIN.

Narrative: AT THE TIME OF THE INCIDENT; I HAD JUST COMPLETED A CLB TO APPROX 10500 FT MSL AND WAS EXITING THE THERMAL. I OBSERVED THE APCHING JET ALREADY CLOSE TO ME AND NEAR/AT MY ALT. WINGS LEVEL; IT WAS ON COURSE TO PASS JUST E OF MY POS. MY HDG WAS ALREADY WBOUND EXITING THE THERMAL. I ACCELERATED (DOVE) TO MAXIMIZE SEPARATION AND MINIMIZE THE RISK OF WAKE TURB. TFC IS A REGULAR CHARACTERISTIC OF THIS AREA AND SURVEILLANCE/AVOIDANCE IS THUS A PRIORITY. NORMALLY; A THERMAL INVERSION CAPS HANG GLIDER OPS AT APPROX 5000 FT MSL. UNDER THESE CONDITIONS; CHIEF CONCERNS ARE FROM DSNDING; SBOUND TFC: COMMERCIAL ACFT; INBOUND TO BUR ARPT; DSNDING ACROSS THE RIDGELINE AT 4000-5000 FT APPROX 2 NM E OF THE INCIDENT LOCATION; AND GA ACFT; INBOUND TO WHITEMAN; BUR AND VNY ARPTS; DSNDING THROUGH THE PACOIMA DAM PASS AT 2500-4500 FT APPROX 4 NM ESE OF THE INCIDENT LOCATION. SCAN ATTN; ALTHOUGH SPREAD UP/DOWN AND IN ALL DIRECTIONS; CAN BE PRIORITIZED UPON THESE FAMILIAR TFC PATTERNS. DSNDING TFC IS COMPARATIVELY EASY TO SPOT AGAINST A BACKGND OF SKY; RATHER THAN GND. AND; BOTH COMMERCIAL AND GA PLTS ARE AWARE OF HANG GLIDER OPS IN THE AREA AND HEIGHTEN THEIR OWN SCANS; AS WELL. HOWEVER; THE DAY'S UNUSUAL WX CONDITIONS CHANGED THIS TYPICAL BAL OF TFC CONCERNS. ABSENT AN INVERSION; THERMAL CLBS TO MORE THAN 10000 FT MSL WERE POSSIBLE. THESE CLBS ADDED A DIFFERENT TFC MIX; INCLUDING GA OPS THROUGH/ABOVE THE NEWHALL PASS; JET TFC CLBING OUT OF VAN NUYS; AND CRUISE TFC ALONG V165. ATTN HAD TO BE SPREAD AMONG CLBING; DSNDING; AND CRUISE TFC ON ALL HDGS. HAVING LEFT LIFT; I WAS DSNDING. THE JET WAS THUS INITIALLY BELOW ME AND DIFFICULT TO DETECT AGAINST THE URBAN BACKGND TO THE S OF MY POS. DESPITE HEIGHTENED AWARENESS; I DID NOT SPOT IT UNTIL IT WAS ALREADY CLOSE TO MY POS. AND I WOULD SUSPECT THAT THE JET'S PLT MAY NOT HAVE BEEN EXPECTING HANG GLIDER TFC AT +10000 FT. EVASIVE ACTION WAS POSSIBLE AND WAS TAKEN. HOWEVER; THE GOAL MUST BE TO REDUCE THE RISK OF A SIMILAR CLOSE ENCOUNTER IN THE FUTURE. THE SIMPLE AND OBVIOUS ANSWER IS THAT I MUST AND SHALL CONTINUE TO IMPROVE MY TFC SCAN SKILLS; ESPECIALLY IN TERMS OF DETECTING CLBING (OR SLIGHTLY-LOWER-ALT) TFC AGAINST AN URBAN/TERRAIN BACKGND. HOWEVER; I ALSO PLAN TO INVESTIGATE THE FEASIBILITY OF MOUNTING A PORTABLE COLLISION ALERT DEVICE AND/OR A XPONDER ON MY HANG GLIDER. SUCH A DEVICE WOULD BE ESPECIALLY USEFUL ON DAYS WHEN WX CONDITIONS PERMIT OPS TO HIGHER-THAN-NORMAL ALTS AND FURTHER AWAY FROM OUR NORMAL PRACTICE AREA. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE REPORTER STATED THAT THIS LOCATION IS POPULAR FOR HANG GLIDING ACTIVITY. A LAUNCH SIGHT IS NEARBY; AND A SUITABLE LANDING AREA IS AVAILABLE. THE ALT ATTAINED IN THIS REPORT WAS UNUSUAL. WHEN CONDITIONS PREVAIL TO ALLOW HIGHER ALTS TO BE ACHIEVED; AN ATTEMPT IS NORMALLY MADE WITH THE LOCAL FSS TO ISSUE A NOTAM. SUCH WAS NOT THE CASE IN THIS INSTANCE.

Data retrieved from NASA's ASRS site as of May 2009 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.