Pilot deviation from assigned altitude. Altitude deviation altitude excursion.

Attributes
ACN	228127
Time
Date	199212
Day	Mon
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : bxk airport : phx
State Reference	AZ
Altitude	msl bound lower : 5000 msl bound upper : 5000
Environment
Flight Conditions	Mixed
Light	Night
Aircraft 1
Controlling Facilities	artcc : zab tracon : phx
Operator	common carrier : air taxi
Make Model Name	Small Transport, Low Wing, 2 Recip Eng
Flight Phase	cruise other other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air taxi
Function	flight crew : single pilot
Qualification	pilot : atp pilot : cfi
Experience	flight time last 90 days : 60 flight time total : 6800 flight time type : 30
ASRS Report	228127
Person 2
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : critical altitude deviation : excursion from assigned altitude inflight encounter : weather inflight encounter other non adherence : clearance non adherence : far
Independent Detector	other flight crewa
Resolutory Action	other
Consequence	other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

I was in cruise flight at 9000 ft, en route from blh to phx. The left front windshield was shattered by an unknown object. I informed ZAB of the situation and asked for a lower altitude and vectors to the nearest airport. I was issued 6000 ft, then later 5000 ft. I was told that 5000 ft was the lowest I could go on the airway. At 5000 ft I was still IMC. I was being vectored to buckeye municipal airport (bxk). When over the airport I was still IMC and unable to locate it. There is no IFR approach to bxk airport. Since I was unable to locate bxk I opted to continue towards phx with the hope of locating another airport. I was handed off to phx approach. Phx approach advised me that the WX at phx was deteriorating. At the same time, I spotted an airport at my 3 O'clock. Phx told me it was bxk. I told them I intended to land there and began my descent. I was never cleared out of 5000 ft and I had never actually declared an emergency. Being so eager to get on the ground I left an assigned altitude without a clearance and without the benefits provided by the PIC's authority to deviate from the rules in an emergency situation.

Original NASA ASRS Text

Title: PLTDEV FROM ASSIGNED ALT. ALTDEV ALT EXCURSION.

Narrative: I WAS IN CRUISE FLT AT 9000 FT, ENRTE FROM BLH TO PHX. THE L FRONT WINDSHIELD WAS SHATTERED BY AN UNKNOWN OBJECT. I INFORMED ZAB OF THE SITUATION AND ASKED FOR A LOWER ALT AND VECTORS TO THE NEAREST ARPT. I WAS ISSUED 6000 FT, THEN LATER 5000 FT. I WAS TOLD THAT 5000 FT WAS THE LOWEST I COULD GO ON THE AIRWAY. AT 5000 FT I WAS STILL IMC. I WAS BEING VECTORED TO BUCKEYE MUNICIPAL ARPT (BXK). WHEN OVER THE ARPT I WAS STILL IMC AND UNABLE TO LOCATE IT. THERE IS NO IFR APCH TO BXK ARPT. SINCE I WAS UNABLE TO LOCATE BXK I OPTED TO CONTINUE TOWARDS PHX WITH THE HOPE OF LOCATING ANOTHER ARPT. I WAS HANDED OFF TO PHX APCH. PHX APCH ADVISED ME THAT THE WX AT PHX WAS DETERIORATING. AT THE SAME TIME, I SPOTTED AN ARPT AT MY 3 O'CLOCK. PHX TOLD ME IT WAS BXK. I TOLD THEM I INTENDED TO LAND THERE AND BEGAN MY DSCNT. I WAS NEVER CLRED OUT OF 5000 FT AND I HAD NEVER ACTUALLY DECLARED AN EMER. BEING SO EAGER TO GET ON THE GND I LEFT AN ASSIGNED ALT WITHOUT A CLRNC AND WITHOUT THE BENEFITS PROVIDED BY THE PIC'S AUTHORITY TO DEVIATE FROM THE RULES IN AN EMER SITUATION.

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.