<< >> NASA ASRS Report 530568, November 2001

C414 pilot descended below minimum charted altitude because he attempted to use a GPS to identify the descent intersection.

Attributes
ACN	530568
Time
Date	200111
Day	Mon
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : isp.airport
State Reference	NY
Altitude	msl bound lower : 1500 msl bound upper : 2000
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : n90.tracon tower : zzz.tower
Operator	general aviation : personal
Make Model Name	Chancellor 414A & C414
Operating Under FAR Part	Part 91
Flight Phase	descent : approach
Route In Use	arrival : on vectors
Flight Plan	IFR
Person 1
Affiliation	other
Function	flight crew : captain oversight : pic
Qualification	pilot : cfi pilot : instrument pilot : multi engine pilot : commercial
Experience	flight time last 90 days : 24 flight time total : 990 flight time type : 110
ASRS Report	530568
Person 2
Affiliation	other
Function	flight crew : first officer
Events
Anomaly	altitude deviation : excursion from assigned altitude inflight encounter : weather inflight encounter other non adherence : clearance non adherence : far non adherence : published procedure other anomaly other
Independent Detector	other controllera
Resolutory Action	controller : issued alert flight crew : returned to assigned altitude none taken : detected after the fact
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I was being vectored for the ILS runway 24 approach at islip airport. The #1 CDI would not pull a flag so I flew the localizer on the #2 CDI. I had to use the GPS to indent coram intersection. The vector appeared to put us well inside coram where once establish the altitude is 1500 ft MSL. The controller cleared us for the approach and said maintain 2000 ft till established. Without verifying I was truly inside coram, I descended to 1500 ft. The controller issued a low altitude alert. I checked the GPS and realized I was 1/2 mi outside coram. I pulled up to 2000 ft. The mistake was assuming I was inside the coram fix and not checking the GPS.

Related reports:

• A320 flight crew reported the FMS descended below one of the...
• Small aircraft pilot descended below cleared altitude due DM...
• A B737 crew descended below 5;000 ft prior to calls intersec...
• An air taxi first officer reported that the crew descended b...
• An air carrier B757-200 descended 400 ft below the 4000 ft c...
• An air carrier mdt jet on the minks 1 arrival received a TCA...

	Enter your search terms Submit search form
	Web www.37000feet.com

Original NASA ASRS Text

Title: C414 PLT DSNDED BELOW MINIMUM CHARTED ALT BECAUSE HE ATTEMPTED TO USE A GPS TO IDENT THE DSCNT INTXN.

Narrative: I WAS BEING VECTORED FOR THE ILS RWY 24 APCH AT ISLIP ARPT. THE #1 CDI WOULD NOT PULL A FLAG SO I FLEW THE LOC ON THE #2 CDI. I HAD TO USE THE GPS TO INDENT CORAM INTXN. THE VECTOR APPEARED TO PUT US WELL INSIDE CORAM WHERE ONCE ESTABLISH THE ALT IS 1500 FT MSL. THE CTLR CLRED US FOR THE APCH AND SAID MAINTAIN 2000 FT TILL ESTABLISHED. WITHOUT VERIFYING I WAS TRULY INSIDE CORAM, I DSNDED TO 1500 FT. THE CTLR ISSUED A LOW ALT ALERT. I CHKED THE GPS AND REALIZED I WAS 1/2 MI OUTSIDE CORAM. I PULLED UP TO 2000 FT. THE MISTAKE WAS ASSUMING I WAS INSIDE THE CORAM FIX AND NOT CHKING THE GPS.

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.