Altitude deviation altitude excursion in a cftt in designated mountainous terrain.

Attributes
ACN	228740
Time
Date	199212
Day	Tue
Local Time Of Day	0001 To 0600
Place
Locale Reference	airport : slc
State Reference	UT
Altitude	msl bound lower : 5800 msl bound upper : 6100
Environment
Flight Conditions	Marginal
Light	Night
Aircraft 1
Controlling Facilities	tracon : slc
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	descent : approach
Route In Use	approach : straight in
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 140 flight time total : 7000 flight time type : 140
ASRS Report	228740
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance non adherence : published procedure other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course flight crew : became reoriented
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

After being cleared for ILS 16R at salt lake city I initiated my descent early out of GS intercept altitude. There is a step down fix at 11.5 DME and at that point I started down thinking I was going down to 6100 ft (GS intercept altitude) however I was already at 6100 ft MSL. I descended down to 5800 ft before realizing my mistake. As I started down I asked my first officer for the GS intercept altitude but he got busy switching over to tower. I started looking at my approach chart and noticed that I was already below where I needed to be. I immediately initiated a climb back up to 6100 ft. I think it is an extreme coincidence that neither my first or so caught this mistake immediately. I briefed the approach during the descent and it is required that the so record the GS intercept altitude and monitor the approach to insure that it is flown properly. I attribute this mistake to extreme fatigue. All 3 of us had been up most of the night and were extremely sleepy. I consider this mistake very serious due to the closeness of the ground in this case. I plan to, in the future bring myself to a much higher level of alertness in this phase of flight.

Original NASA ASRS Text

Title: ALTDEV ALT EXCURSION IN A CFTT IN DESIGNATED MOUNTAINOUS TERRAIN.

Narrative: AFTER BEING CLRED FOR ILS 16R AT SALT LAKE CITY I INITIATED MY DSCNT EARLY OUT OF GS INTERCEPT ALT. THERE IS A STEP DOWN FIX AT 11.5 DME AND AT THAT POINT I STARTED DOWN THINKING I WAS GOING DOWN TO 6100 FT (GS INTERCEPT ALT) HOWEVER I WAS ALREADY AT 6100 FT MSL. I DSNDED DOWN TO 5800 FT BEFORE REALIZING MY MISTAKE. AS I STARTED DOWN I ASKED MY FO FOR THE GS INTERCEPT ALT BUT HE GOT BUSY SWITCHING OVER TO TWR. I STARTED LOOKING AT MY APCH CHART AND NOTICED THAT I WAS ALREADY BELOW WHERE I NEEDED TO BE. I IMMEDIATELY INITIATED A CLB BACK UP TO 6100 FT. I THINK IT IS AN EXTREME COINCIDENCE THAT NEITHER MY FIRST OR SO CAUGHT THIS MISTAKE IMMEDIATELY. I BRIEFED THE APCH DURING THE DSCNT AND IT IS REQUIRED THAT THE SO RECORD THE GS INTERCEPT ALT AND MONITOR THE APCH TO INSURE THAT IT IS FLOWN PROPERLY. I ATTRIBUTE THIS MISTAKE TO EXTREME FATIGUE. ALL 3 OF US HAD BEEN UP MOST OF THE NIGHT AND WERE EXTREMELY SLEEPY. I CONSIDER THIS MISTAKE VERY SERIOUS DUE TO THE CLOSENESS OF THE GND IN THIS CASE. I PLAN TO, IN THE FUTURE BRING MYSELF TO A MUCH HIGHER LEVEL OF ALERTNESS IN THIS PHASE OF FLT.

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.