National Transportation Safety Board
Aviation Accident Final Report

 

 

Location:

Mead, CO

Accident Number:

DEN02LA103

Date & Time:

09/08/2002, 0930 MDT

Registration:

N551SA

Aircraft:

Adler SA-1

Aircraft Damage:

Destroyed

Defining Event:

 

Injuries:

1 Fatal

Flight Conducted Under:

Part 91: General Aviation - Personal

Analysis

Witnesses observed "a rotor or a wing" separate from the gyroplane, and the gyroplane then descended and impacted terrain. 

According to the deputy's report, a rotor blade was found about 150 feet north of the point of impact, and other debris was strewn to the southwest. The co-builder of the accident gyroplane, who was also a close friend of the pilot, contacted three gyroplane experts: the designer of the SA-1 Dominator and President of Rotor Flight Dynamics; a gyroplane aerodynamist; and the designer of another gyroplane.  They examined the wreckage and compiled both a factual and analytical report. The following is based on the factual portion of the report. The separated rotor blade was bowed upward and had fractured about 2 feet from the tip. The fracture was consistent with positive overload. There was orange paint and primer transfer marks on the top and upper leading edge (the tail cone was painted orange). The attached rotor blade was also bent upward. The propeller blades exhibited no strike marks. The rotor head and hub bar were intact. The hub bar, normally bent 2.5 degrees upward, was bent approximately 10 degrees upward. The roll pillow blocks bore evidence of hammering and were mushroomed. The pitch stops were similarly damaged. In the analytical portion of the report, the necessity of maintaining blade loading at all times in order to maintain main rotor blade rotation was noted. The fracture on the separated main rotor blade was in "a purely upward bending moment which could only have occurred if the blade rpm had dramatically slowed...If totally unloaded, the blade rpm can deteriorate as fast as 120 rpm/sec." Normal rotor blade rpm is 320 to 400 rpm. If rotor blade rpm were allowed to drop, increasing the velocity of air moving through the rotor system, severe blade "flapping" would result as evidenced by the pounding and mushrooming of the roll pillow blocks and bending of the hub bar on the rotor head. A toxicological test revealed 2.024 (ug/mL, ug/g) paroxetine in the blood and liver. The drug is an antidepressant and contraindicated for flight.  The pilot's personal physician prescribed the drug for the treatment of fibromyalgia, a condition manifested by muscle soreness. Adverse effects of the drug include drowsiness, muscle weakness, agitation, and tremors.

 

Probable Cause and Findings

The National Transportation Safety Board determines the probable cause(s) of this accident to be:
the pilot's failure to maintain main rotor rpm, resulting in blade flapping, subsequent blade contact with the airframe, and loss of control.

Findings

 

Occurrence #1: LOSS OF CONTROL - IN FLIGHT
Phase of Operation: MANEUVERING

Findings
1. (C) ROTOR RPM - NOT MAINTAINED - PILOT IN COMMAND
2. USE OF INAPPROPRIATE MEDICATION/DRUG - PILOT IN COMMAND
3. (C) ROTOR SYSTEM,MAIN ROTOR - OSCILLATION
----------

Occurrence #2: IN FLIGHT COLLISION WITH TERRAIN/WATER
Phase of Operation: DESCENT - UNCONTROLLED

Findings
4. TERRAIN CONDITION - GRASS
5. TERRAIN CONDITION - OPEN FIELD

 

Factual Information

On September 8, 2002, approximately 0930 mountain daylight time, an Adler SA-1 gyroplane, N551SA, registered to and operated by the pilot, was destroyed when it impacted terrain and burned near Mead, Colorado. The private pilot was fatally injured. Day visual meteorological conditions prevailed, and no flight plan had been filed for the personal flight being conducted under Title 14 CFR Part 91. The local flight originated approximately 0900 from the Jefferson County (Jeffco) Airport, Broomfield, Colorado.

Two witnesses told a sheriff's deputy that the gyroplane sounded as if it was "struggling." Two other witnesses submitted written statements. One witness said that he "could tell the aircraft was having mechanical problems." The gyroplane dropped about 1,000 feet, "lost a wing" and began to "spin and tumble out of control." Another witness said he heard the engine either "miss or stall slightly," and also saw "a rotor or a wing" come off in flight. All four witnesses saw smoke as the gyroplane impacted terrain and immediately caught fire.

According to the deputy's report, a rotor blade was found about 150 feet north of the point of impact, and other debris was strewn to the southwest. The impact site was circular in shape, approximately 5 to 6 meters  (16 to 20 feet) in diameter. The accident occurred 0.25-mile south of (Weld) county road 32 and 0.25-mile west of county road 13, at a location of 40 degrees, 12'48.30" north latitude, and 104 degrees, 57'02.80" west longitude.

The co-builder of the accident gyroplane --- a physician and a close friend of the pilot --- contacted three gyroplane experts: the designer of the SA-1 Dominator and President of Rotor Flight Dynamics; a gyroplane aerodynamist; and the designer of another gyroplane. They examined the wreckage and compiled both a factual and analytical report. The following is based on the factual portion of the report.

The separated rotor blade was bowed upward and had fractured about 2 feet from the tip. The fracture was consistent with positive overload. There was orange paint and primer transfer marks on the top and upper leading edge (the tail and nose cones were painted orange). The attached rotor blade was also bent upward. The propeller blades exhibited no strike marks. The rotor head and hub bar were intact. The hub bar, normally bent 2.5 degrees upward, was found bent approximately 10 degrees upward. The roll pillow blocks bore evidence of hammering and were mushroomed. The pitch stops were similarly damaged.

The analytical portion of the report noted the necessity of maintaining blade loading at all times in order to maintain main rotor blade rotation. The fractured main rotor blade was "a purely upward bending moment which could only have occurred if the blade rpm had dramatically slowed…If totally unloaded, the blade rpm can deteriorate as fast as 120 rpm/sec." Normal rotor blade rpm is 320 to 400 rpm. If rotor blade rpm were allowed to drop and the velocity of air moving through the rotor system were to increase, severe blade "flapping" would result. The rotor head had been subjected to severe blade flapping as evidenced by the pounding and mushrooming of the roll pillow blocks and the bent hub bar. The authors said there is no in-flight maneuver that can lead to blade flapping at normal rotor rpms. Only the unloading of the rotor blades will do this.

FAA's Civil Aeromedical Institute (CAMI) conducted a toxicological screen on specimens taken from the pilot and found 2.024 (ug/mL, ug/g) paroxetine in the blood. According to a CAMI toxicologist, paroxetine is an antidepressant and contraindicated. Some of the adverse effects include drowsiness, muscle weakness, agitation, and tremors." When advised of these results, the physician/co-builder of N551SA contacted the pilot's personal physician and learned that he had prescribed the drug for the treatment of fibromyalgia, a condition manifested by muscle soreness.

 

 

 

Pilot Information

Certificate:

Private

Age:

51, Male

Airplane Rating(s):

Single-engine Land

Seat Occupied:

Single

Other Aircraft Rating(s):

Gyroplane

Restraint Used:

Seatbelt, Shoulder harness

Instrument Rating(s):

None

Second Pilot Present:

No

Instructor Rating(s):

None

Toxicology Performed:

No

Medical Certification:

Class 3 Valid Medical--w/ waivers/lim.

Last FAA Medical Exam:

04/13/2001

Occupational Pilot:

 

Last Flight Review or Equivalent:

02/16/2002

Flight Time:

280 hours (Total, all aircraft), 44 hours (Total, this make and model), 222 hours (Pilot In Command, all aircraft), 44 hours (Last 90 days, all aircraft), 18 hours (Last 30 days, all aircraft), 3 hours (Last 24 hours, all aircraft)

 

 

Aircraft and Owner/Operator Information

Aircraft Make:

Adler

Registration:

N551SA

Model/Series:

SA-1

Aircraft Category:

Gyroplane

Year of Manufacture:

 

Amateur Built:

Yes

Airworthiness Certificate:

Experimental

Serial Number:

001

Landing Gear Type:

Tricycle

Seats:

1

Date/Type of Last Inspection:

06/18/2002, Condition

Certified Max Gross Wt.:

900 lbs

Time Since Last Inspection:

44 Hours

Engines:

1 Reciprocating

Airframe Total Time:

44 Hours at time of accident

Engine Manufacturer:

Rotax

ELT:

Not installed

Engine Model/Series:

912WLS

Registered Owner:

Steven H. Adler

Rated Power:

100 hp

Operator:

Steven H. Adler

Operating Certificate(s) Held:

None

 

Meteorological Information and Flight Plan

Conditions at Accident Site:

Visual Conditions

Condition of Light:

Day

Observation Facility, Elevation:

DEN, 5431 ft msl

Distance from Accident Site:

25 Nautical Miles

Observation Time:

0953 MDT

Direction from Accident Site:

135°

Lowest Cloud Condition:

Few / 9000 ft agl

Visibility

10 Miles

Lowest Ceiling:

None

Visibility (RVR):

 

Wind Speed/Gusts:

4 knots /

Turbulence Type Forecast/Actual:

/

Wind Direction:

140°

Turbulence Severity Forecast/Actual:

/

Altimeter Setting:

30.12 inches Hg

Temperature/Dew Point:

24°C / 8°C

Precipitation and Obscuration:

 

Departure Point:

Broomfield, CO (BJC)

Type of Flight Plan Filed:

None

Destination:

 (BJC)

Type of Clearance:

None

Departure Time:

0900 MDT

Type of Airspace:

Class E

 

 

Wreckage and Impact Information

Crew Injuries:

1 Fatal

Aircraft Damage:

Destroyed

Passenger Injuries:

N/A

Aircraft Fire:

On-Ground

Ground Injuries:

N/A

Aircraft Explosion:

None

Total Injuries:

1 Fatal

Latitude, Longitude:

40.214167, -104.950278

 


 


Administrative Information

Investigator In Charge (IIC):

Arnold W Scott

Report Date:

04/01/2003

Additional Participating Persons:

Mark A Schofield; FAA Flight Standards District Office; Denver, CO

Publish Date:

 

Investigation Docket:

NTSB accident and incident dockets serve as permanent archival information for the NTSB’s investigations. Dockets released prior to June 1, 2009 are publicly available from the NTSB’s Record Management Division at pubinq@ntsb.gov, or at 800-877-6799. Dockets released after this date are available at http://dms.ntsb.gov/pubdms/.