Narrative:

I was at 11000 ft on an IFR clearance in very turbulent; gusty; and windy WX. I would estimate that we were in light to medium chop. The aircraft was difficult to control and maintain altitude as there were periods of rising and descending air. The airspeed was varying from 10-20 KTS due to the wind gusts that were causing the turbulence. One min we would be in rising air causing me to push the nose down to prevent getting tossed above my assigned altitude. I relaxed the nose down pressure when the airspeed got near the maneuvering speed (va). When went into sink I raised the nose and added power in an attempt to maintain altitude. When the airspeed got to 10 KTS above the stall speed; I decreased the pitch to maintain airspeed. Despite all attempts; there were times when the lift and sink overcame the corrective actions and caused the aircraft to soar up or down beyond the assigned altitude. Center called a debonair at 12 O'clock position and 5 mi. Neither myself nor the person in the right seat ever saw the other aircraft. About 10 mins later; center called and gave me a phone number to call. Upon landing; I complied and explained the problems we were having. The person at center said they had lost separation but there was no deviation. They just wanted to know what happened. I am at a loss to recommend a way to avoid such an incident ever happening in the future. A C172 is a light aircraft. The rising air currents over the desert on a warm day can easily overpwr the small engine and light airframe that make up the aircraft. My airspeed varied from 65-105 KTS in very turbulent air. To go slower or faster would have set me up for a stall or exceeding va in turbulent conditions; neither option did I want to occur. The only thing I can think of is that if I am in rising air; any aircraft above or below me is in the same column of air. Depending on the size and weight of the aircraft would indicate how much they would be effective. Perhaps in turbulent air such as we experienced center could move aircraft left or right in order for the radar returns on their scopes to show a separation if the aircraft are not in sight.

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Original NASA ASRS Text

Title: C172 PLT HAS TROUBLE MAINTAINING ALT IN TURBULENT WX.

Narrative: I WAS AT 11000 FT ON AN IFR CLRNC IN VERY TURBULENT; GUSTY; AND WINDY WX. I WOULD ESTIMATE THAT WE WERE IN LIGHT TO MEDIUM CHOP. THE ACFT WAS DIFFICULT TO CTL AND MAINTAIN ALT AS THERE WERE PERIODS OF RISING AND DSNDING AIR. THE AIRSPD WAS VARYING FROM 10-20 KTS DUE TO THE WIND GUSTS THAT WERE CAUSING THE TURB. ONE MIN WE WOULD BE IN RISING AIR CAUSING ME TO PUSH THE NOSE DOWN TO PREVENT GETTING TOSSED ABOVE MY ASSIGNED ALT. I RELAXED THE NOSE DOWN PRESSURE WHEN THE AIRSPD GOT NEAR THE MANEUVERING SPD (VA). WHEN WENT INTO SINK I RAISED THE NOSE AND ADDED PWR IN AN ATTEMPT TO MAINTAIN ALT. WHEN THE AIRSPD GOT TO 10 KTS ABOVE THE STALL SPD; I DECREASED THE PITCH TO MAINTAIN AIRSPD. DESPITE ALL ATTEMPTS; THERE WERE TIMES WHEN THE LIFT AND SINK OVERCAME THE CORRECTIVE ACTIONS AND CAUSED THE ACFT TO SOAR UP OR DOWN BEYOND THE ASSIGNED ALT. CTR CALLED A DEBONAIR AT 12 O'CLOCK POS AND 5 MI. NEITHER MYSELF NOR THE PERSON IN THE R SEAT EVER SAW THE OTHER ACFT. ABOUT 10 MINS LATER; CTR CALLED AND GAVE ME A PHONE NUMBER TO CALL. UPON LNDG; I COMPLIED AND EXPLAINED THE PROBS WE WERE HAVING. THE PERSON AT CTR SAID THEY HAD LOST SEPARATION BUT THERE WAS NO DEV. THEY JUST WANTED TO KNOW WHAT HAPPENED. I AM AT A LOSS TO RECOMMEND A WAY TO AVOID SUCH AN INCIDENT EVER HAPPENING IN THE FUTURE. A C172 IS A LIGHT ACFT. THE RISING AIR CURRENTS OVER THE DESERT ON A WARM DAY CAN EASILY OVERPWR THE SMALL ENG AND LIGHT AIRFRAME THAT MAKE UP THE ACFT. MY AIRSPD VARIED FROM 65-105 KTS IN VERY TURBULENT AIR. TO GO SLOWER OR FASTER WOULD HAVE SET ME UP FOR A STALL OR EXCEEDING VA IN TURBULENT CONDITIONS; NEITHER OPTION DID I WANT TO OCCUR. THE ONLY THING I CAN THINK OF IS THAT IF I AM IN RISING AIR; ANY ACFT ABOVE OR BELOW ME IS IN THE SAME COLUMN OF AIR. DEPENDING ON THE SIZE AND WT OF THE ACFT WOULD INDICATE HOW MUCH THEY WOULD BE EFFECTIVE. PERHAPS IN TURBULENT AIR SUCH AS WE EXPERIENCED CTR COULD MOVE ACFT L OR R IN ORDER FOR THE RADAR RETURNS ON THEIR SCOPES TO SHOW A SEPARATION IF THE ACFT ARE NOT IN SIGHT.

Data retrieved from NASA's ASRS site as of January 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.