DEN06IA056

NTSB incident investigation · Swearingen SA226TC · Denver, CO · April 5, 2006

Incident · No injuriesIncident investigationFinal report
Date
April 5, 2006, 06:23 local (12:23 UTC)
Place
Denver, CO
Injuries
1 uninjured
Damage
No damage
Phase of flight
Initial climb
Aircraft
N770SSwearingen SA226TC
Weather
Visual (VMC) · Dawn
Status
Completed · report August 29, 2006
Report
Approved by Office Director
Parties
Federal Aviation Administration
Case key
63460

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

On this page

Probable cause

the failure of the elevator down cable due to an improperly routed cable by unknown maintenance personnel. A contributing factor was the improper inspection of the elevator cable by the operator's maintenance personnel.

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.

Airframe/component/system failure/malfunctionTakeoff - initial climb
Maintenance,installation - improperOther maintenance personnelCause
Maintenance,inspection - improperCompany maintenance personnelFactor
Flt control syst,elevator control cable/rod - failure,totalCause
Precautionary landing - performedPilot in command

Analysis

Prior to departure, the pilot completed the pre-takeoff checklist, which included checking the flight controls. While at 80-85 knots during the takeoff roll, the pilot "noticed pitch seemed very light. At rotation speed, [pilot] pulled back on yoke and aircraft left ground. At this point, yoke came back all the way back and aircraft began to quickly pitch upward." The pilot reported that moving the yoke forward had no effect and it felt disconnected from the elevators. The pilot quickly began to trim nose down and reduced power to stop excessive nose up pitch. After gaining marginal control of the aircraft, the pilot advised air traffic control he had a "flight control problem" and requested a return for landing. During the downwind leg to runway 17L, the pilot "experimented with various configurations...to determine the method of approach and landing." The pilot executed a gradual descent to the runway and landed uneventfully. Examination of the airplane by company maintenance personnel revealed that "the elevator down cable was improperly routed at the pulley in the vertical stab, just below the elevator bell crank. This caused the cable to wear against a guide until the cable failed." The aircraft underwent an inspection 10 days prior to the incident. According to the inspection checklist, the elevator cables and related components were inspected with no anomalies noted. Upon discovery of the improper routed cable, the operator checked the other 18 aircraft in their fleet. No discrepanices were found.

Factual narrative

On April 5, 2006, at 0623 mountain daylight time, a Swearingen SA226TC twin-engine turboprop airplane, N770S, operated as Key Lime 515, sustained an in-flight failure of an elevator control cable during initial climb from the Denver International Airport, Denver, Colorado. The airplane was registered to EDB Air, Inc., Wilsonville, Oregon, and operated by Key Lime Air, Inc., Englewood, Colorado. Visual meteorological conditions prevailed at the time of the incident. The unscheduled domestic cargo flight was being operated under the provisions of Title 14 Code of Federal Regulations Part 135 under an instrument flight rules flight plan. The airline transport pilot, who was the sole occupant, was not injured. The flight was originating at the time of the incident and was en route to Dodge City, Kansas.

According to a statement provided by the pilot, prior to departure he completed the pre-takeoff checklist, which included checking the flight controls. While at 80-85 knots during the takeoff roll, the pilot "noticed pitch seemed very light. At rotation speed, [pilot] pulled back on yoke and aircraft left ground. At this point, yoke came back all the way back and aircraft began to quickly pitch upward." The pilot reported that moving the yoke forward had no effect and it felt disconnected from the elevators. The pilot quickly began to trim nose down and reduced power to stop excessive nose up pitch. After gaining marginal control of the aircraft, the pilot advised air traffic control he had a "flight control problem" and requested a return for landing.

During the downwind leg to runway 17L, the pilot "experimented with various configurations...to determine the method of approach and landing." The pilot executed a gradual descent to the runway and landed uneventfully.

Examination of the airplane by company maintenance personnel revealed that "the elevator down cable was improperly routed at the pulley in the vertical stab, just below the elevator bell crank. This caused the cable to wear against a guide until the cable failed." Upon discovery of the improper routed cable, the operator checked the other 18 aircraft in their fleet. No discrepancies were found.

According to the aircraft maintenance records, the elevator cable was installed by another operator on February 4, 1998, as required by Airworthiness Directive 87-02-02. Key Lime Air, Inc. maintained the aircraft under a manufacturer approved continuous airworthiness inspection program. On March 24, 2006, the aircraft underwent a "Letter Check E" inspection. According to the inspection checklist, the elevator cables and related components were inspected with no anomalies noted.

Aircraft

Registration
N770S
Reported as
Swearingen SA226TC
Category
Airplane
Serial number
TC-248
Airframe hours
32,479
Engine
Garrett TPE-331-10UA, 715 hp, turbo prop
Damage
No damage
Flight
Part 135
Registered owner
Key Lime Air
Airworthiness certificate
Standard, Normal
Last inspection
Continuous airworthiness · March 1, 2006
Departed
DEN · Denver, CO
Destination
DDC · Dodge City, KS
Flight plan
IFR
Airport
DEN · Denver Intl

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
38
Injuries
None
Certificate
Airline transport
Airplane ratings
Single-engine land, Multi-engine land
Instrument ratings
Airplane
Medical
Class 2, Without waivers/limitations
Last flight review
November 1, 2005
Seat
Left
Flight hours
201 in the last 90 days · 82 in the last 30 days

Weather

Conditions
Visual (VMC) · Dawn
Wind
210° at 12 knots, gusting 18
Visibility
10 statute miles
Lowest ceiling
None
Temperature
77 °F, dew point 21 °F
Altimeter
29.67 inHg
Observed at
DEN