Corporate pilot descends below assigned altitude.

Attributes
ACN	213194
Time
Date	199206
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : psk
State Reference	VA
Altitude	msl bound lower : 13400 msl bound upper : 14000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : corporate
Make Model Name	Small Transport, Low Wing, 2 Turboprop Eng
Flight Phase	cruise other
Route In Use	enroute airway : zdc
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : atp
Experience	flight time last 90 days : 34 flight time total : 7885 flight time type : 3600
ASRS Report	213194
Person 2
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	other controllera
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

In cruise flight 90 northeast of psk while resetting RNAV and enjoying solo leg of trip, center called for altitude check. I replied I was at 13400. I was assigned 14000. Center advised no clearance given. I acknowledged. I was offered a descent clearance but opted to return to 14000. Center 127.92 advised of gravity of situation. I was aware of it. Problem developed when I reset the RNAV system and was comparing them. I placed a pack of crackers on the console. The crackers bumped the altitude hold button on the autoplt and while I enjoyed the outside view, the aircraft slowly descended. The only excuse was faulty xchk on my part and attention outside of cockpit. When 1 function is deleted, there are no bells or flashing lights as with autoplt disengage. Aircraft not equipped with alerter. WX was cavu from 8000 up, with a scattered layer at 8. After 2 weeks of rainy WX, I let my attention wander during a cavu leg. When IFR, fly it (IFR). No conflicts with traffic. Controller almost as upset with me as I was. Since I was the only one in the aircraft, it had to be my fault. Only mitigating factor was this was only third trip as single pilot in over a yr, got lazy. Some fatigue or stress due to pending job change. After I regained my composure, I asked the controller if there would be any problems from this. He replied not from his end. The incident was very disturbing to me, long after it was over, even though there was no conflict. I thought I was too professional to ring a bell (300 ft) let alone 600 ft. Pro's work during and relax after the flight, not during.

Original NASA ASRS Text

Title: CORPORATE PLT DSNDS BELOW ASSIGNED ALT.

Narrative: IN CRUISE FLT 90 NE OF PSK WHILE RESETTING RNAV AND ENJOYING SOLO LEG OF TRIP, CTR CALLED FOR ALT CHK. I REPLIED I WAS AT 13400. I WAS ASSIGNED 14000. CTR ADVISED NO CLRNC GIVEN. I ACKNOWLEDGED. I WAS OFFERED A DSCNT CLRNC BUT OPTED TO RETURN TO 14000. CTR 127.92 ADVISED OF GRAVITY OF SITUATION. I WAS AWARE OF IT. PROBLEM DEVELOPED WHEN I RESET THE RNAV SYS AND WAS COMPARING THEM. I PLACED A PACK OF CRACKERS ON THE CONSOLE. THE CRACKERS BUMPED THE ALT HOLD BUTTON ON THE AUTOPLT AND WHILE I ENJOYED THE OUTSIDE VIEW, THE ACFT SLOWLY DSNDED. THE ONLY EXCUSE WAS FAULTY XCHK ON MY PART AND ATTN OUTSIDE OF COCKPIT. WHEN 1 FUNCTION IS DELETED, THERE ARE NO BELLS OR FLASHING LIGHTS AS WITH AUTOPLT DISENGAGE. ACFT NOT EQUIPPED WITH ALERTER. WX WAS CAVU FROM 8000 UP, WITH A SCATTERED LAYER AT 8. AFTER 2 WKS OF RAINY WX, I LET MY ATTN WANDER DURING A CAVU LEG. WHEN IFR, FLY IT (IFR). NO CONFLICTS WITH TFC. CTLR ALMOST AS UPSET WITH ME AS I WAS. SINCE I WAS THE ONLY ONE IN THE ACFT, IT HAD TO BE MY FAULT. ONLY MITIGATING FACTOR WAS THIS WAS ONLY THIRD TRIP AS SINGLE PLT IN OVER A YR, GOT LAZY. SOME FATIGUE OR STRESS DUE TO PENDING JOB CHANGE. AFTER I REGAINED MY COMPOSURE, I ASKED THE CTLR IF THERE WOULD BE ANY PROBLEMS FROM THIS. HE REPLIED NOT FROM HIS END. THE INCIDENT WAS VERY DISTURBING TO ME, LONG AFTER IT WAS OVER, EVEN THOUGH THERE WAS NO CONFLICT. I THOUGHT I WAS TOO PROFESSIONAL TO RING A BELL (300 FT) LET ALONE 600 FT. PRO'S WORK DURING AND RELAX AFTER THE FLT, NOT DURING.

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.