FTW95IA013

NTSB incident investigation · Gates Learjet 35A · San Antonio, TX · October 11, 1994

Incident · No injuriesIncident investigationFinal report
Date
October 10, 1994, 19:00 local (Oct 11, 1994, 00:00 UTC)
Place
San Antonio, TX
Injuries
2 uninjured
Damage
Minor damage
Phase of flight
Enroute
Aircraft
N46TJGates Learjet 35A
Weather
Visual (VMC) · Day
Status
Completed · report May 16, 1995
Report
Approved by Office Director
FAA report
19941010040859I
Case key
19257

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

The uncontained failure of the turbine wheel. A factor was the resultant loss of hydraulic power.

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 power(total) - mech failure/malfClimb
Turbine assembly,turbine wheel - disintegratedCause
Reason for occurrence undetermined
Hydraulic system,line - cut/severedFactor
Loss of control - on ground/waterLanding - roll
Directional control - not possiblePilot in command
OverrunLanding - roll

Analysis

During a climb through FL200, the crew heard a noise, followed by the loss of power from the right engine and a yaw. They secured the right engine and continued on to their destination. An inspection of the right engine revealed that the number 3 turbine wheel had failed and that the failure was uncontained. The failure also severed the hydraulic lines in the equipment bay and separated the bay door. The pieces of the turbine wheel were not recovered. During the landing roll the crew exited on a taxiway but did not have sufficient control to stay on the taxiway. The airplane came to rest in the grass.

Factual narrative

On October 10, 1994, approximately 1900 central daylight time, a Gates Learjet Corp. 35A, N46TJ, received minor damage during an uncontained engine failure climb. The airplane, owned by a Mexican corporation and flown by two commercial pilots, was on a cross country positioning flight. An IFR flight plan was filed and in effect and visual meteorological conditions prevailed. Neither pilot was injured.

In their written report the crew reported that they were en route from Laredo, Texas, to Dallas, Texas, and climbing through FL200, when they "heard a noise, right engine suddenly stopped, and the airplane began to yaw." They secured the right engine, executed the emergency check list, and requested to divert to San Antonio. During the descent, the crew noticed they had no hydraulic pressure and that activation of the hydraulic pump did not restore pressure. During the ensuing landing, the crew was "unable to stay on the taxiway and came to a stop a few yards beyond the taxiway in the grass."

Initial examination revealed that the right engine cowling had punctures from the inside out. After the cowling was removed there was physical evidence that the number 3 turbine wheel had experienced a failure and that the failure was uncontained. Pieces of the turbine wheel had also penetrated the fuselage in the area of the equipment bay. The pieces entering the equipment bay also severed the hydraulic lines and separated the bay door.

All pieces of the number 3 turbine wheel were lost following the uncontained failure resulting in no metallurgical testing being performed.

Aircraft

Registration
N46TJ
Reported as
Gates Learjet 35A
Category
Airplane
Serial number
077
Engine
Garrett TFE-731-2, 3,500 lbs thrust, turbo fan
Damage
Minor damage
Flight
Positioning · Part 91
Registered owner
Aeroservicos Demex, S.A.
Airworthiness certificate
Standard, Transport
Departed
LRD · Laredo, TX
Destination
DAL · Dallas, TX
Flight plan
IFR

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
47
Certificate
Commercial
Airplane ratings
Multi-engine land
Instrument ratings
Airplane
Medical
Class 2, Valid Medical--w/ waivers/lim
Seat
Left
Flight hours
5,504 total · 208 in this make and model · 5,000 as pilot in command · 160 in the last 90 days · 60 in the last 30 days · 3 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
30° at 8 knots
Visibility
10 statute miles
Lowest ceiling
None
Temperature
72 °F, dew point 39 °F
Altimeter
30.00 inHg
Observed at
SAT, 60 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.