MIA03LA181

NTSB accident investigation · Schweizer 269C-1 · Homestead, FL · September 11, 2003

Accident · Minor injuriesLimited investigationFinal report
Date
September 11, 2003, 14:45 local (18:45 UTC)
Place
Homestead, FL
Injuries
2 minor
Damage
Substantial damage
Phase of flight
Landing
Aircraft
N6147QSchweizer 269C-1
Weather
Visual (VMC) · Day
Status
Completed · report August 3, 2006
Report
Approved by Office Director
Parties
Schweizer Aircraft Corporation, FAA Flight Standards District Office
FAA report
20030911023439A
Case key
57948

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

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Probable cause

the inadequate 100-hour inspection of the helicopter by other maintenance personnel who failed to discover that the landing gear dampers had low pressure, which resulted in ground resonance and subsequent substantial damage during a run-on landing.

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.

Miscellaneous/otherLanding
Landing gear,main gear shock absorbing strut - low pressure
Maintenance,100-hour inspection - inadequateOther maintenance personnelCause
Run on landing - performedPilot in command(cfi)
Ground resonance - encounteredPilot in command(cfi)

Analysis

The certified flight instructor (CFI) stated that after departure the flight proceeded to the Homestead General Airport where he advised the student that the lesson would continue with "running landing" and "running take off" training from the previous day. The flight continued in the traffic pattern for runway 36, and when on short final approach to the runway at 5 feet above ground level, the helicopter was at 25 knots indicated airspeed. The helicopter contacted the runway with the skids parallel to the runway centerline, and the CFI allowed the helicopter to continue sliding. The CFI advised the student that the lesson would conclude with a "running takeoff", and upon lifting off the runway at an indicated airspeed of 35 knots, he noticed a vibration from the main rotor system. He noticed the rpm was decreasing and touched down again on the runway, at which time the helicopter began to "shake violently." He realized the flight had encountered ground resonance, and noticed that there was insufficient main rotor rpm to lift off the ground to stabilize the vibrating rotor blade system. He lowered the collective but felt a force when he attempted to reduce throttle input; he felt the force was the student pilot applying throttle input. At that point he was contacted in the head, lost consciousness, which he regained in the hospital. The student pilot advised a Federal Aviation Administration (FAA) inspector that when the flight was approximately 30 feet above ground level prior to performing a running landing, the CFI took the controls from him. The flight continued and while sliding on the runway, the CFI started screaming and froze on the controls. He (student pilot) then braced for impact. Following recovery of the helicopter, the landing gear and main rotor dampers were removed for further examination at the manufacturer's facility with FAA oversight. Examination of the main rotor blade dampers revealed all three exhibited damage associated from lead lag motions encountered in ground resonance. Examination of the four landing gear dampers which had been installed when the helicopter was manufactured revealed all tested out of limits for charge pressure (low). The helicopter was last inspected in accordance with a 100-Hour inspection on August 11, 2003; the helicopter had accumulated 87.9 hours since the inspection at the time of the accident. Review of the 100-Hour inspection guide revealed the landing gear dampers are required to be inspected for operation and condition, and for damper extension with a full fuel tank. Review of Section 12 of the Basic Handbook of Maintenance Instructions manual indicates the landing gear dampers will experience a decrease in pressure with subsequent use of the helicopter, and they should be extension checked during a 100-Hour inspection, or every six months, whichever occurs first. According to a memorandum from the Director of Flight Training to all flight instructors dated August 25, 2003, with respect to the Dominican Republic Flight Training Program, running landings were prohibited to be demonstrated and practiced until a new order was given.

Factual narrative

On September 11, 2003, about 1445 eastern daylight time, a Schweizer 269C-1, N6147Q, registered to Caribbean Helicopter Leasing, Inc., operated by Helicenter International Academy, was substantially damaged during a run-on landing at the Homestead General Aviation Airport, Homestead, Florida. Visual meteorological conditions prevailed at the time and no flight plan was filed for the 14 CFR Part 91 instructional flight from the Kendall-Tamiami Executive Airport, Miami, Florida, to the Homestead General Aviation Airport, Homestead, Florida. The certified flight instructor (CFI) and student sustained minor injuries. The flight originated at 1430, from the Kendall-Tamiami Executive Airport.

The CFI stated that after departure the flight proceeded to the Homestead General Airport where he advised the student that the lesson would continue with "running landing" and "running take off" training from the previous day. The flight continued in the traffic pattern for runway 36, and when on short final approach to the runway at 5 feet above ground level, the helicopter was at 25 knots indicated airspeed. The helicopter contacted the runway with the skids parallel to the runway centerline, and the CFI allowed the helicopter to continue sliding. The CFI advised the student that the lesson would conclude with a "running takeoff", and upon lifting off the runway at an indicated airspeed of 35 knots, he noticed a vibration from the main rotor system. He noticed the rpm was decreasing and touched down again on the runway, at which time the helicopter began to "shake violently." He realized the flight had encountered ground resonance, and noticed that there was insufficient main rotor rpm to lift off the ground to stabilize the vibrating rotor blade system. He lowered the collective but felt a force when he attempted to reduce throttle input; he felt the force was the student pilot applying throttle input. At that point he was contacted in the head, lost consciousness, which he regained in the hospital.

The student pilot advised a Federal Aviation Administration (FAA) inspector that when the flight was approximately 30 feet above ground level prior to performing a running landing, the CFI took the controls from him. The flight continued and while sliding on the runway, the CFI started screaming and froze on the controls. He (student pilot) then braced for impact.

Following recovery of the helicopter, the landing gear and main rotor dampers were removed for further examination at the manufacturer's facility with FAA oversight. Examination of the main rotor blade dampers revealed all three exhibited damage associated from lead lag motions encountered in ground resonance. Examination of the four landing gear dampers which had been installed when the helicopter was manufactured revealed all tested out of limits for charge pressure (low).

The helicopter was last inspected in accordance with a 100-Hour inspection on August 11, 2003; the helicopter had accumulated 87.9 hours since the inspection at the time of the accident. Review of the 100-Hour inspection guide revealed the landing gear dampers are required to be inspected for operation and condition, and for damper extension with a full fuel tank. Review of Section 12 of the Basic Handbook of Maintenance Instructions manual indicates the landing gear dampers will experience a decrease in pressure with subsequent use of the helicopter, and they should be extension checked during a 100-Hour inspection, or every 6 months, whichever occurs first.

According to a memorandum from the Director of Flight Training to all flight instructors dated August 25, 2003, with respect to the Dominican Republic Flight Training Program, running landings were prohibited to be demonstrated and practiced until a new order was given.

The helicopter minus the retained main rotor and landing gear dampers was released to the president and CEO of the owner of the helicopter on November 18, 2003. The retained main rotor and landing gear dampers were released to the president and CEO of the owner of the helicopter on March 23, 2004.

Aircraft

Registration
N6147Q
Reported as
Schweizer 269C-1
Category
Helicopter
Serial number
0068
Airframe hours
3,150.5
Engine
Lycoming HO-360-C1A, 180 horsepower, reciprocating
Damage
Substantial damage
Flight
Instructional · Part 91
Operator
Helicenter International Academy
Registered owner
Caribbean Helicopter Leasing, Inc.
Airworthiness certificate
Standard, Normal
Last inspection
100 hour · August 11, 2003 · 87.9 hours before
Departed
KTMB · Miami, FL
Destination
X51 · Homestead, FL
Airport
X51 · Homestead General Aviation, runway 36, 4,000 × 100 ft, asphalt

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 · 2

As NTSB recorded them. NTSB leaves out names.

Role
Flight instructor
Age
32
Injuries
Minor
Certificates
Commercial, Flight instructor
Medical
Class 2, Valid Medical--w/ waivers/lim
Last flight review
August 5, 2003
Seat
Left
Flight hours
218 total · 25 in this make and model · 25 in the last 90 days · 25 in the last 30 days · 4 in the last 24 hours
Role
Student pilot
Age
20
Injuries
Minor
Certificate
Student
Medical
Class 3, Valid Medical--no waivers/lim.
Seat
Right
Flight hours
17 total · 17 in this make and model · 17 in the last 90 days · 17 in the last 30 days · 1 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
Variable at 5 knots
Visibility
10 statute miles
Lowest ceiling
None
Temperature
91 °F, dew point 73 °F
Altimeter
29.93 inHg
Observed at
KTMB

FAA reports on this event · 1

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