Pilot of cpr small transport aircraft descended below approach procedure prescribed altitude resulti...

Attributes
ACN	227107
Time
Date	199211
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : 3ck
State Reference	IL
Altitude	msl bound lower : 1400 msl bound upper : 2300
Environment
Flight Conditions	IMC
Light	Dusk
Aircraft 1
Controlling Facilities	tracon : ord artcc : zau
Operator	general aviation : corporate
Make Model Name	Small Transport, Low Wing, 2 Recip Eng
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : cfi pilot : atp
Experience	flight time last 90 days : 150 flight time total : 7000 flight time type : 1050
ASRS Report	227107
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : published procedure other spatial deviation
Independent Detector	atc equipment other atc equipment : unspecified other controllera
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I was ready to go home this afternoon when a company that operates an small transport aircraft and an small transport aircraft called me to ask if could fly a trip to fort dodge, ia, for them that evening in their small transport?! Their pilot was on vacation. I had flown earlier and was tired, but I reluctantly accepted. I had not flown this particular aircraft model before but I have many hours in type. I currently fly aircraft model models and although I have many hours in the 'B' model, I hadn't flown one in many yrs. I took off for 3CK to pick up my passenger. I was cleared for the VOR 26 approach to the airport. I was inbound when approach called me and said they showed me below mins. I immediately initiated a climb and told approach I was doing so, back to 2300 ft. I was down to 1400 ft when he called! I checked the kns-80 DME and immediately saw my problem. I had the kns-80 in the RNAV mode when I thought it was in the VOR mode! I had started my descent to MDA 11.0 DME out from the airport, not from the VOR like I had assumed! This caused me to start my descent 5.6 mi too early! I completed the approach with no further problems but I felt awful. I know that unfamiliarity with this aircraft had caused me to divert my attention from setting up the approach properly! Additionally I was fatigued and should not have taken this trip! As you can see from the following letter, my troubles were not over yet! In the future, if I'm tired and not up to flying, I will decline any trips that come my way! Additionally, I do not intend to fly unfamiliar aircraft in lousy IFR WX. Callback conversation with reporter revealed the following information: reporter stated that he learned to not hurry to fly unfamiliar aircraft in WX conditions and believes that ATC saved his life by their intervention. He further stated that 'the following letter' reference was referring to another ASRS report acn 227108 wherein he deviated from altitude due to accidentally 'kicking off' the autoplt.

Original NASA ASRS Text

Title: PLT OF CPR SMT ACFT DSNDED BELOW APCH PROC PRESCRIBED ALT RESULTING IN ATC ADVISING THAT THE ACFT WAS BELOW MINS.

Narrative: I WAS READY TO GO HOME THIS AFTERNOON WHEN A COMPANY THAT OPERATES AN SMT ACFT AND AN SMT ACFT CALLED ME TO ASK IF COULD FLY A TRIP TO FORT DODGE, IA, FOR THEM THAT EVENING IN THEIR SMT?! THEIR PLT WAS ON VACATION. I HAD FLOWN EARLIER AND WAS TIRED, BUT I RELUCTANTLY ACCEPTED. I HAD NOT FLOWN THIS PARTICULAR ACFT MODEL BEFORE BUT I HAVE MANY HRS IN TYPE. I CURRENTLY FLY ACFT MODEL MODELS AND ALTHOUGH I HAVE MANY HRS IN THE 'B' MODEL, I HADN'T FLOWN ONE IN MANY YRS. I TOOK OFF FOR 3CK TO PICK UP MY PAX. I WAS CLRED FOR THE VOR 26 APCH TO THE ARPT. I WAS INBOUND WHEN APCH CALLED ME AND SAID THEY SHOWED ME BELOW MINS. I IMMEDIATELY INITIATED A CLB AND TOLD APCH I WAS DOING SO, BACK TO 2300 FT. I WAS DOWN TO 1400 FT WHEN HE CALLED! I CHKED THE KNS-80 DME AND IMMEDIATELY SAW MY PROBLEM. I HAD THE KNS-80 IN THE RNAV MODE WHEN I THOUGHT IT WAS IN THE VOR MODE! I HAD STARTED MY DSCNT TO MDA 11.0 DME OUT FROM THE ARPT, NOT FROM THE VOR LIKE I HAD ASSUMED! THIS CAUSED ME TO START MY DSCNT 5.6 MI TOO EARLY! I COMPLETED THE APCH WITH NO FURTHER PROBLEMS BUT I FELT AWFUL. I KNOW THAT UNFAMILIARITY WITH THIS ACFT HAD CAUSED ME TO DIVERT MY ATTN FROM SETTING UP THE APCH PROPERLY! ADDITIONALLY I WAS FATIGUED AND SHOULD NOT HAVE TAKEN THIS TRIP! AS YOU CAN SEE FROM THE FOLLOWING LETTER, MY TROUBLES WERE NOT OVER YET! IN THE FUTURE, IF I'M TIRED AND NOT UP TO FLYING, I WILL DECLINE ANY TRIPS THAT COME MY WAY! ADDITIONALLY, I DO NOT INTEND TO FLY UNFAMILIAR ACFT IN LOUSY IFR WX. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT HE LEARNED TO NOT HURRY TO FLY UNFAMILIAR ACFT IN WX CONDITIONS AND BELIEVES THAT ATC SAVED HIS LIFE BY THEIR INTERVENTION. HE FURTHER STATED THAT 'THE FOLLOWING LETTER' REF WAS REFERRING TO ANOTHER ASRS RPT ACN 227108 WHEREIN HE DEVIATED FROM ALT DUE TO ACCIDENTALLY 'KICKING OFF' THE AUTOPLT.

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.

Pilot of cpr small transport aircraft descended below approach procedure prescribed altitude resulting in ATC advising that the aircraft was below mins.