What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
Aircraft N1704U fifteen minutes out of bet on flight to klg in cruise at 1000 feet. Engine made very loud whine noise and started losing power. PIC called bet on company frequency (130.70) to report situation. PIC set up for landing on small pond (5.5 miles north of Akiachak) with engine producing some power. While on downwind engine lost all power and PIC realized he would not make it to the pond so he found high tundra. PIC kept flaps up to make it to clearer area. Left side of horizontal stabilizer struck small trees and nose wheel fork broke on impact with tundra. Engine case cracked at #2 journal when crankshaft broke. No fire. ELT did not activate, PIC and passengers said inpact forces were low. PIC and passengers evacuated aircraft until PIC determined it was safe to return for shelter. PIC and 2 passengers uninjured. Flight following in bet received PIC distress messages and initiated recovery per manual procedures.
Amendment- 6/7/2013- received tear-down report from Continental motors:
Yute dom originally thought the crankshaft was broke but the tear-down report is different:
Examiner signature: phillip grice
Date: may 15, 2013
Date engine model engine serial no. aircraft registration page 5-15-2013 IO520DCF 175037 N1704U
General information:
Examination engine received
Date may 15, 2013
Facility Continental motors inc. rga # 250415
Mobile, Alabama
Address 2039 broad street 36615
From alaskan aircraft engines
Ntsb/faa tagged yes
Box sealed yes
Engine information:
Make Continental motors inc.
Model IO520DCF
Serial no. 175037
Engine position single
Total time 3085.7
Time soh 1329.7 10/12/2011
Build date 08-26-1981
In service date not reported
Removal date 03-12-2013
Aircraft / accident information
Aircraft make Cessna
Aircraft model 207
Aircraft serial no. 20700304
Registration no. N1704U (information from engine log book)
Accident date March 26,2013
Accident location Akiachak AK.
Significant logbook information:
Only installation and removal entries in logbook.
Report summary: the number one piston eci part number AEC648045/Z was fractured at the piston pin bore, releasing the number one rod and piston pin assembly at the small end. The unsupported number one rod and piston pin assembly caused extreme mechanical damage to the rear section of the crankcase and camshaft. The number one rod released from the crankshaft, exhibited extreme mechanical damage and was found in the oil sump. There were no signs of lubrication distress. Portions of the eci piston skirt were recovered from the oil sump and inspected in the cmi lab.
The number one cylinder, piston, rod, and sump contents were retained in bonded storage until the NTSB iic determines disposition of the engine and the parts.
Amended section 21 c thru f of this report to identify number 1 piston.
Operator will amend SDR report.
As the FAA filed it
AIRCRAFT N1704U FIFTEEN MINUTES OUT OF BET ON FLIGHT TO KLG IN CRUISE AT 1000 FEET. ENGINE MADE VERY LOUD WHINE NOISE AND STARTED LOSING POWER. PIC CALLED BET ON COMPANY FREQUENCY (130.70) TO REPORT SITUATION. PIC SET UP FOR LANDING ON SMALL POND (5.5 MILES NORTH OF AKIACHAK) WITH ENGINE PRODUCING SOME POWER. WHILE ON DOWNWIND ENGINE LOST ALL POWER AND PIC REALIZED HE WOULD NOT MAKE IT TO THE POND SO HE FOUND HIGH TUNDRA. PIC KEPT FLAPS UP TO MAKE IT TO CLEARER AREA. LEFT SIDE OF HORIZONTAL STABILIZER STRUCK SMALL TREES AND NOSE WHEEL FORK BROKE ON IMPACT WITH TUNDRA. ENGINE CASE CRACKED AT #2 JOURNAL WHEN CRANKSHAFT BROKE. NO FIRE. ELT DID NOT ACTIVATE, PIC AND PASSENGERS SAID INPACT FORCES WERE LOW. PIC AND PASSENGERS EVACUATED AIRCRAFT UNTIL PIC DETERMINED IT WAS SAFE TO RETURN FOR SHELTER. PIC AND 2 PASSENGERS UNINJURED. FLIGHT FOLLOWING IN BET RECEIVED PIC DISTRESS MESSAGES AND INITIATED RECOVERY PER MANUAL PROCEDURES.
AMENDMENT- 6/7/2013- RECEIVED TEAR-DOWN REPORT FROM CONTINENTAL MOTORS:
YUTE DOM ORIGINALLY THOUGHT THE CRANKSHAFT WAS BROKE BUT THE TEAR-DOWN REPORT IS DIFFERENT:
EXAMINER SIGNATURE: PHILLIP GRICE
DATE: MAY 15, 2013
DATE ENGINE MODEL ENGINE SERIAL NO. AIRCRAFT REGISTRATION PAGE 5-15-2013 IO520DCF 175037 N1704U
GENERAL INFORMATION:
EXAMINATION ENGINE RECEIVED
DATE MAY 15, 2013
FACILITY CONTINENTAL MOTORS INC. RGA # 250415
MOBILE, ALABAMA
ADDRESS 2039 BROAD STREET 36615
FROM ALASKAN AIRCRAFT ENGINES
NTSB/FAA TAGGED YES
BOX SEALED YES
ENGINE INFORMATION:
MAKE CONTINENTAL MOTORS INC.
MODEL IO520DCF
SERIAL NO. 175037
ENGINE POSITION SINGLE
TOTAL TIME 3085.7
TIME SOH 1329.7 10/12/2011
BUILD DATE 08-26-1981
IN SERVICE DATE NOT REPORTED
REMOVAL DATE 03-12-2013
AIRCRAFT / ACCIDENT INFORMATION
AIRCRAFT MAKE CESSNA
AIRCRAFT MODEL 207
AIRCRAFT SERIAL NO. 20700304
REGISTRATION NO. N1704U (INFORMATION FROM ENGINE LOG BOOK)
ACCIDENT DATE MARCH 26,2013
ACCIDENT LOCATION AKIACHAK AK.
SIGNIFICANT LOGBOOK INFORMATION:
ONLY INSTALLATION AND REMOVAL ENTRIES IN LOGBOOK.
REPORT SUMMARY: THE NUMBER ONE PISTON ECI PART NUMBER AEC648045/Z WAS FRACTURED AT THE PISTON PIN BORE, RELEASING THE NUMBER ONE ROD AND PISTON PIN ASSEMBLY AT THE SMALL END. THE UNSUPPORTED NUMBER ONE ROD AND PISTON PIN ASSEMBLY CAUSED EXTREME MECHANICAL DAMAGE TO THE REAR SECTION OF THE CRANKCASE AND CAMSHAFT. THE NUMBER ONE ROD RELEASED FROM THE CRANKSHAFT, EXHIBITED EXTREME MECHANICAL DAMAGE AND WAS FOUND IN THE OIL SUMP. THERE WERE NO SIGNS OF LUBRICATION DISTRESS. PORTIONS OF THE ECI PISTON SKIRT WERE RECOVERED FROM THE OIL SUMP AND INSPECTED IN THE CMI LAB.
THE NUMBER ONE CYLINDER, PISTON, ROD, AND SUMP CONTENTS WERE RETAINED IN BONDED STORAGE UNTIL THE NTSB IIC DETERMINES DISPOSITION OF THE ENGINE AND THE PARTS.
AMENDED SECTION 21 C THRU F OF THIS REPORT TO IDENTIFY NUMBER 1 PISTON.
OPERATOR WILL AMEND SDR REPORT.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.
Other reports on N1704U · 3
Matched to the same aircraft by N-number and date.