MIA94IA040

NTSB incident investigation · Israel Aircraft Industries 1124 · Melbourne, FL · December 19, 1993

Incident · No injuriesIncident investigationFinal report
Date
December 19, 1993, 00:15 local (05:15 UTC)
Place
Melbourne, FL
Injuries
9 uninjured
Damage
Minor damage
Phase of flight
Enroute
Aircraft
N74JMIsrael Aircraft Industries 1124
Weather
Instrument (IMC) · Night/dark
Status
Completed · report September 13, 1994
Report
Approved by Office Director
FAA report
19931219051299I
Case key
37438

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the incident.

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Probable cause

Was inadequate quality control by the engine manufacturer which resulted in failure of the second stage low pressure turbine disk due to a machining anomaly and reduced fatigue strength due to sub standard heat treat processing.

Sequence of events

NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.

Loss of engine powerCruise
Inadequate quality controlManufacturerCause
Turbine assembly,turbine wheel - previous damageCause
Turbine assembly,turbine wheel - fatigueCause
Turbine assembly,turbine wheel - failure,totalCause

Analysis

The flight experienced an uncontained failure of the number two engine while in cruise flight. An uneventful landing was made. Examination of the number two engine indicated the second stage low pressure turbine disk experienced separation of a small segment near the disk rim. Metallurgical examination indicated the separation was due to a machining anomaly and reduced fatigue life due to sub standard heat treat of the disk material.

Factual narrative

On December 19, 1993, about 0015 eastern standard time, a Israel Aircraft Industries 1124, N74JM, registered to Turnberry Charters, Inc., experienced an uncontained failure of the no. 2 engine while in cruise flight near Melbourne, Florida, while on a 14 CFR Part 91 corporate flight. Visual meteorological conditions prevailed at the time and an instrument flight rules flight plan was filed. The aircraft received minor damage and the two pilots and seven passengers were not injured. The flight originated at Daytona Beach, Florida, on December 19, 1993, about 0000.

The first officer stated that shortly after they leveled at 29,000 feet and set cruise engine power they felt severe vibration and heard unusual noises. They observed the no. 2 engine had lost power. They shut down the no. 2 engine and diverted to Orlando, Florida.

Postlanding examination of the aircraft by an FAA inspector indicated the no. 2 engine had sustained damage in the turbine section and that a component had exited the engine through the turbine case, engine cowling, and tail pipe. The third stage low pressure turbine wheel (LPT-3)was recovered from inside the roof of a house in Melbourne, Florida.

Examination of the no. 2 was conducted at Allied Signal Engines, Phoenix, Arizona. Examination revealed "the second stage low pressure turbine wheel (LPT-2) experienced a separation of a small segment of the disk near the rim. The separation resulted in rotational unbalance of the low pressure turbine rotating group and expulsion of the LPT-3 wheel overboard. Metallurgical analysis of the LPT revealed the rim separation of the 2nd LPT to be primary with all other damage secondary. The 2nd LPT separated due to a machining anomaly in a blade slot in combination with sub standard heat treat process resulting in reduced fatigue life." See attached Allied Signal Engines report.

Aircraft

Registration
N74JM
Reported as
Israel Aircraft Industries 1124
Category
Airplane
Serial number
WW-1124A
Airframe hours
3,723
Engine
Garrett TFE-731-3-1G, 3,700 lbs thrust, turbo fan
Damage
Minor damage
Flight
Executive/Corporate · Part 91
Registered owner
Turnberry Charters, Inc.
Airworthiness certificate
Standard, Normal
Last inspection
AAIP · October 18, 1993 · 37 hours before
Departed
DAB · Daytona Beach, FL
Destination
FLL · Fort Lauderdale, FL
Flight plan
IFR

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
36
Certificate
Airline transport
Airplane ratings
Multi-engine land, Single-engine sea, Single-engine land
Instrument ratings
Airplane
Medical
Class 1, Valid Medical--no waivers/lim.
Seat
Left
Flight hours
4,500 total · 2,400 in this make and model · 3,325 as pilot in command

Weather

Conditions
Instrument (IMC) · Night/dark
Wind
290° at 5 knots
Visibility
0.5 statute miles
Temperature
55 °F, dew point 55 °F
Altimeter
30.00 inHg
Observed at
MLB, 3 nm away

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.