ILLNESS REDUCES PERFORMANCE LEADING TO DSNDING BELOW GS DANGEROUSLY.

Narrative

I WAS APCHING GEG ON THE ILS RWY 3 APCH. WHILE ON THE FINAL APCH I DSNDED BELOW THE GS UNINTENTIONALLY APPROX 2-3 MI FROM THE RWY THRESHOLD. I COULD SEE THE GND BELOW BUT DID NOT HAVE THE RWY IN SIGHT. I WAS NOTIFIED BY TWR THAT RADAR INDICATED A LOW ALT WARNING. I THEN NOTICED THAT I HAD FLOWN A FULL SCALE DEFLECTION BELOW THE GS. I MADE A CORRECTION WITH PITCH AND PWR TO REGAIN THE GS; BUT IN THE PROCESS DRIFTED TO NEAR A FULL SCALE DEFLECTION TO THE L OF THE LOC BY THE TIME I SAW THE RWY NEAR THE THRESHOLD. I WAS APPROX 200 FT TO THE L OF THE RWY NEAR THE THRESHOLD. I WAS ABLE TO CORRECT FOR THIS AND LANDED LONG ON THE RWY WITHOUT FURTHER DIFFICULTY. EVENTS LEADING TO THE PROB: ON THE DAY OF THE OCCURRENCE; I HAD ALREADY BEEN SUFFERING 2 DAYS FROM WHAT I THOUGHT WAS A MILD COLD. THAT MORNING; PRIOR TO THE FLT; I FELT REASONABLY WELL AND HAD TAKEN ONLY 2 ASPIRIN. I HAD NOT BEEN USING ANY DECONGESTANT; ANTIHISTAMINE OR ANY OTHER MEDICATION. I FELT STRONG AND DID NOT SEE ANY NEED TO POSTPONE THE FLT. HOWEVER; WHEN THE WORKLOAD BEGAN TO INCREASE AS I APCHED THE FINAL APCH FIX; I BEGAN HAVING DIFFICULTY KEEPING UP WITH THE AIRPLANE (A PRESSURIZED SMT). THE PWR AND AIRSPD WERE TOO HIGH WHILE XING THE FAF. WHILE TRYING TO CORRECT THIS; I WAS DISTRACTED FROM MY INST SCANNING AND EVENTS WERE HAPPENING RAPIDLY. I FOUND MYSELF TRYING TO CATCH UP WITH THE AIRPLANE. WHEN NOTIFIED BY TWR THAT I WAS TOO LOW; I HAD THE GND IN SIGHT AND WAS A FEW HUNDRED FT ABOVE THE GND. I THEREFORE DID NOT FEEL ANY IMMINENT DANGER AND DECIDED TO RECAPTURE THE GS AND PROCEED WITH THE APCH. BY THE MIDDLE OF THAT AFTERNOON; I BEGAN TO FEEL MUCH MORE ILL AND HAD DEVELOPED THE FLU WITH A LOW GRADE FEVER. I BELIEVE THAT THE ILLNESS HAD EFFECTED MY JUDGEMENT AND REACTION TIME DURING THAT FLT. NORMALLY I WOULD HAVE DONE A MISSED APCH UNDER SUCH CIRCUMSTANCES AND WOULD HAVE BEEN BETTER PREPARED FOR THE SECOND ATTEMPT AT THE APCH. FORTUNATELY I WAS ABLE TO LAND UNEVENTFULLY; BUT THE THOUGHT OF WHAT COULD HAVE HAPPENED STILL HAUNTS ME. THE MORAL: DON'T FLY IF YOU ARE SICK!