Sunday, April 12, 2020

Glider Tow Event: SZD-48 Jantar Standard 2, N456RM; fatal accident occurred April 14, 2018 near La Belle Municipal Airport (X14), Hendry County, Florida

Forward view of wreckage showing fragmented cockpit parts and instrument panel.

Aft view of wreckage showing damaged vertical and horizontal stabilizers. 

Right-side view of wreckage showing damaged right wing and crushed cockpit.

Left-side view of wreckage showing damaged left wing.

Front view of wreckage showing the crushed cockpit.

View of damaged instrument panel within the debris path.

 Nano Flight Data Recorder S/N: 1NH(02141).

As recorded flight path (orange) and adjusted flight path (blue) for the accident flight.

Accident flight with time and altitude noted.

Altitude and speed versus time for accident flight.

Images of the speed brake connecting rod assembly as received: a) side view and b) threaded rod axial view.

a) Image of the threaded rod fracture surface and b) side view of the threaded section at an angle of approximately 35° to the clevis and beveled gear rotation axis.

Overview SEM image of the fracture surface.

SEM images of typical fracture surface features from regions; ductile dimple morphology in matte region and b) flat faceted fracture in specular region.

Tom Irlbeck, a lifelong lover of aviation, died in a glider crash April 14th, 2018. He logged more than 30,000 hours flying. He was an avid outdoorsman with two sons, five grandchildren and married to Katy Irlbeck for 48 years.

Tom Irlbeck taught his oldest son Jon how to fly when he was 14. Jon Irlbeck, 48, will continue his dad's flying legacy as a commercial airline pilot.

Tom Irlbeck, who split his later years between Wisconsin and Florida, built this RV-8. He then painted it in Navy colors and flew it frequently.

Tom Irlbeck, who became a Cape Coral winter resident in 2003, was an original 'Top Gun' instructor and flew almost 200 combat missions in Vietnam.

The National Transportation Safety Board traveled to the scene of this accident.

Additional Participating Entity:

Federal Aviation Administration / Flight Standards District Office; Miramar, Florida

Aviation Accident Factual Report - National Transportation Safety Board:

Investigation Docket - National Transportation Safety Board:

Location: LaBelle, FL
Accident Number: ERA18FA128
Date & Time: 04/14/2018, 1540 EDT
Registration: N456RM
Aircraft: S.Z.D. SZD 48 JANTAR STD 2
Aircraft Damage: Substantial
Defining Event: Glider tow event
Injuries: 1 Fatal
Flight Conducted Under: Part 91: General Aviation - Personal 

On April 14, 2018, about 1540 eastern daylight time, an SZD-48 Jantar Standard 2 glider, N456RM, was substantially damaged after it impacted the ground near LaBelle Municipal Airport, LaBelle, Florida. The private pilot was fatally injured. The airplane was registered to and operated by the private pilot as a Title 14 Code of Federal Regulations Part 91 personal flight. Visual meteorological conditions prevailed at the time of the accident, and no flight plan was filed for the local flight.

The witness who assisted the pilot in assembling the glider before the flight stated that the assembly was "normal." After affixing the wings to the fuselage, a positive control check was completed and the pilot prepared for takeoff. The glider was then attached to the tow rope of the tow airplane, and the glider was positioned on runway 14.

The tow pilot, who had towed the pilot's glider for the past 5 years reported that he and the glider pilot were in radio communication before takeoff. According to the tow pilot, the pilot requested a "left break" after takeoff, which was precautionary in case the tow rope broke on climbout. The tow pilot was not concerned with the pilot's request because the wind was aligned with the departure runway. The tow pilot also stated that the glider pilot requested to be towed up to "3,000 ft above the field before release" and that the tow pilot acknowledged this request.

During the initial climbout, when the glider was about 200 ft above ground level (agl), the tow pilot noticed that the tow rope had a lot of slack, which did not seem normal. He also stated that the glider was "moving around a lot more than [the tow pilot] was accustomed to." The tow pilot started a shallow turn to the right to keep the glider upwind and "take up the slack in the tow rope." After this maneuver, the slack remained in the tow rope, which affected the glider's airspeed. When the glider was at 400 ft agl, it encountered a thermal and began to climb rapidly and the tow rope lifted the tail of the tow airplane. The tow pilot was about to release the glider from the tow rope, but the glider released on its own. The tow pilot continued straight ahead in level flight to avoid the glider; afterward, he noticed that the glider was about 200 ft below the tow airplane in a spin. The glider continued to spin until it impacted the ground.

Data retrieved from a Nano flight data recorder that was onboard the glider indicated that, when the glider reached an altitude of 400 ft agl, its airspeed was 75 knots. The glider reached a maximum altitude of 485 ft about 12 seconds later then descended to 472 ft about 6 seconds later. At that time, the glider's airspeed reached its lowest point, which was about 55 knots. No other flight information was recorded.

Pilot Information

Certificate: Airline Transport; Flight Instructor
Age: 74, Male
Airplane Rating(s): Multi-engine Land; Single-engine Land; Single-engine Sea
Seat Occupied: Single
Other Aircraft Rating(s): Glider
Restraint Used:
Instrument Rating(s): Airplane
Second Pilot Present: No
Instructor Rating(s): Airplane Single-engine; Glider
Toxicology Performed:Yes 
Medical Certification: Class 3 None
Last FAA Medical Exam: 05/18/2017
Occupational Pilot: Yes
Last Flight Review or Equivalent:
Flight Time:  (Estimated) 25000 hours (Total, all aircraft), 42 hours (Total, this make and model) 

According to Federal Aviation Administration (FAA) records, the glider pilot held a commercial pilot certificate with ratings for airplane single- and multiengine land, glider, and instrument airplane. The pilot held a flight instructor certificate with ratings for single-engine land and glider. He reported a total flight experience of 25,000 hours, including 71 hours during the last 6 months, on his FAA third-class medical certificate application, dated May 18, 2017.

A review of the pilot's logbook revealed that it was his third glider logbook. The logbook indicated that the pilot had over 406.1 hours of total flight experience in gliders. Further review showed that the pilot had accumulated a total of 42.4 hours in the accident glider, of which 19.6 hours were in the 90 days before the accident.

Aircraft and Owner/Operator Information

Aircraft Make: S.Z.D.
Registration: N456RM
Model/Series: SZD 48 JANTAR STD 2 1
Aircraft Category: Glider
Year of Manufacture: 1981
Amateur Built:No 
Airworthiness Certificate: Normal
Serial Number: B-1216
Landing Gear Type: Tandem
Seats: 1
Date/Type of Last Inspection: 11/01/2017, Annual
Certified Max Gross Wt.: 860 lbs
Time Since Last Inspection:
Airframe Total Time: 697 Hours as of last inspection
Engine Manufacturer:
ELT: Not installed
Engine Model/Series:
Registered Owner: On file
Rated Power:
Operator: On file
Operating Certificate(s) Held: None

According to FAA airworthiness records, the glider was manufactured in 1981 as a one-seat, standard-class, high-performance glider. It was a glass fiber-reinforced epoxy resin construction with frames, ribs, and a center section truss, built up from welded steel tubes, to support the wings; a single-wheel retractable undercarriage; and a towing hook. The cockpit was covered by a two-piece plexiglass canopy with a fixed forward portion and a rearward hinged portion, and the cockpit instruments were on a panel in the central pedestal between the pilot's legs. Aluminum plate-style airbrakes extended from upper and lower surfaces of the wing. A maintenance logbook excerpt revealed that the glider received its most recent annual inspection on November 1, 2017, at a tachometer time of 697 hours.

The accident glider was not equipped with ballast.

According to an excerpt from section 4.5.4 of the flight manual, which discussed spinning, the height loss during recovery from a spin is about 328 ft or more depending on the recovery procedure.

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation: IMM, 37 ft msl
Distance from Accident Site: 18 Nautical Miles
Observation Time: 1535 EDT
Direction from Accident Site:355° 
Lowest Cloud Condition: Clear
Visibility:  10 Miles
Lowest Ceiling: None
Visibility (RVR):
Wind Speed/Gusts: 11 knots /
Turbulence Type Forecast/Actual: 
Wind Direction: 160°
Turbulence Severity Forecast/Actual:
Altimeter Setting: 29.98 inches Hg
Temperature/Dew Point: 34°C / 14°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: LaBelle, FL (X14)
Type of Flight Plan Filed: None
Destination: LaBelle, FL (X14)
Type of Clearance: None
Departure Time: 1535 EDT
Type of Airspace: Class G

At 1535, the recorded weather at Immokalee Regional Airport, Immokalee, Florida, which was about 18 nautical miles north of the accident site, included wind from 160° at 11 knots, 10 statute miles visibility, clear skies, temperature 34°C, dew point 14°C, and altimeter setting 29.98 inches of mercury.

Airport Information

Airport: LA BELLE MUNI (X14)
Runway Surface Type: Asphalt
Airport Elevation: 20 ft
Runway Surface Condition: Dry
Runway Used:14 
IFR Approach: None
Runway Length/Width: 5254 ft / 75 ft
VFR Approach/Landing: None

Wreckage and Impact Information

Crew Injuries: 1 Fatal
Aircraft Damage: Substantial
Passenger Injuries: N/A
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 1 Fatal
Latitude, Longitude: 26.727778, -81.420556 

Examination of the accident site revealed that the glider came to rest in a cow pasture about 1/2 mile southeast of the airport. The glider was orientated on a 030° magnetic heading, with the debris field extending outward 75 ft from the initial impact crater. All flight control surfaces were accounted for at the accident site.

Examination of the fuselage revealed that the cockpit hull was fragmented aft of the wing attachment assembly, and all flight controls and pushrods were exposed. The instrument panel, which was also located within the debris field, sustained impact damage and thus did not provide any reliable information. The aileron pushrods were traced back to the quick locks aft of the wing spars. Both quick locks were intact and did not show signs of damage. The airbrake control was traced to the airbrake assembly in the fuselage and, when manipulated, rotated the airbrake tubes within the fuselage. The elevator pushrod was traced back to the empennage and, when moved, revealed continuity. The empennage was broken away from the fuselage and impact damaged. The pushrods for the elevator and rudder were impact damaged and, when moved, revealed continuity.

Examination of the left wing revealed that the leading edge exhibited crush damage. The wing remained intact throughout the span of the wing. The aileron control tube was manipulated, and continuity was established to the aileron. The attachment fitting on the aileron control tube, which was connected to a quick lock in the fuselage, was impact damaged. The left wing was partially attached to the fuselage, displaced forward, and impact damaged at the wing root. Examination of the airbrake revealed that it was in the extended position. When the airbrake control tube was rotated, the airbrake retracted. The airbrake control tube was broken at its attachment fitting, and the control wheel was impact damaged.

Examination of the right wing revealed that the outboard section of the wing was fragmented and that the aileron was separated from its attachment points. The aileron control tube was manipulated, and continuity was established to the aileron attachment fitting. The attachment fitting, which connected to the other quick lock in the fuselage, was impact damaged. The right wing was partially attached to the fuselage and impact damaged at the wing root. Examination of the airbrake revealed that it was in the stowed position. The airbrake control tube was rotated, and the airbrake deployed. The control tube was impact damaged at the gear fitting at fuselage beveled gear assembly.

The Nano flight data recorder found at the accident site was sent to the National Transportation Safety Board's Vehicle Performance Division for data download.

Medical And Pathological Information

The District 21 Medical Examiner, Fort Myers, Florida, performed an autopsy on the pilot. His cause of death was multiple blunt force injuries.

Toxicology testing performed at the FAA Forensic Sciences Laboratory was negative for carbon monoxide, ethanol, and drugs.

Additional Information

The SZD-48 Jantar Standard 2 glider flight manual, section 4.5.3, notes the following information about stalling:

NOTE: The sailplane does not warn before stalling!

The stalling in straight flight takes place with nose high above horizon and considerable elevator up deflection. Before stalling the distinct fuselage oscillations appear as well as the oscillation of airspeed indicator hint, when the airspeed drops down to about 68 km/h [36 knots] light pilot without ballast or 85 km/h [45 knots] heavy pilot with ballast.

In the same time the oscillation range decreases to about 10 km/h [5 knots]. During dropping of sailplane, the lateral balance can be retained. Recovery by releasing of stick is sure and easy.

The stalling in circling appears as a tendency for diminishing the circling radius and is accompanied with the airspeed indicator hint oscillations.

In 30° banked turn the stalling airspeed is about 78 km/h [42 knots] light pilot without ballast or about 88 km/h [47 knots] heavy pilot with ballast.

During dropping down the lateral balance can be retained. Recovery without troubles. The height loss in stalling at turn with water ballast exceeds 50 m [164 ft]. 

1 comment:

  1. RIP sir and thank you for your military and civilian service as an airline captain.