History of the Flight
The aircraft, a Luscombe 8A registration N2837K, departed Navan Airfield at 15:00 UTC with the pilot and one passenger for a VFR flight to Weston Aerodrome (EIWT). The enroute portion was uneventful, and the aircraft landed at EIWT at 15:40 UTC. After a lunch break without refuelling, the aircraft took off again at 17:15 UTC for the return leg to Navan.
Accident Sequence
During the easterly approach to the grass runway at Navan Airfield, at approximately 400 metres from the threshold, the indicated airspeed was 55 mph. At about 200 feet above the ground, after selecting carburetor heat to cold, the pilot noticed a faster-than-normal loss of height, airspeed dropping to 50 mph, and the aircraft drifting left of the centreline. The pilot lowered the nose and applied full power while attempting to turn back right. Airspeed did not increase, control inputs had no effect on regaining the centreline, and up elevator had no effect on slowing the descent rate. The aircraft struck a fence post on the left side of the approach path. The pilot levelled the wings before touching down in a field left abeam the approach path. The aircraft bounced, struck a second wooden post, and entered a deep ditch left of the runway threshold. Both the pilot and passenger evacuated without injury. There was no fire.
Site Examination
The aircraft was found in a near-vertical nose-down condition in a deep vegetated ditch. A line of wooden posts separated the approach path from an adjacent field. The sixth post exhibited significant fresh impact damage from its top to 0.75 metres from the ground. A first ground impact mark was found approximately 20 metres further on from the first post. A second post along the ditch line also showed impact damage in the form of a vertical slice.
Damage to Aircraft
The fuselage failed at the aft bulkhead. The empennage remained connected to the fuselage solely by elevator and rudder control cables, which cut into the lower rear fuselage skin. The left side of the rear fuselage suffered indentation damage. The left wing leading edge of the tailplane was severely indented. Outer sections of both wings, especially the left, suffered extensive damage. The left main undercarriage strut collapsed rearwards. The propeller had impact damage: 100 mm of one blade separated in forward bending; the other blade bent forward and was stained with earth, indicating rotation under power. Splinters of creosoted wood were found under a protruding screw head on the left fuselage. The aircraft was damaged beyond economic repair.
Meteorological Information
Met Éireann provided meteorological data: Surface wind was 090/10 knots, gradient wind 120/15 knots. Cloud was few/scattered at 2,200 ft, broken at 6,000 ft (cumulus and stratocumulus). Visibility was 30+ km. No weather was reported. Air temperature was 14°C, dew point 5°C. The freezing level was about 4,000 ft. The forecaster commented that the surface wind was well established and not varying; no gusts were recorded upstream. Tephigrams showed no significant vertical wind shear in the lowest levels, and radar/satellite showed no Cumulonimbus or shower activity near Navan.
Aircraft Information
The Luscombe 8A is an all-metal, two-place, high-wing monoplane powered by a Continental A65-8 four-cylinder horizontally-opposed air-cooled 65 hp engine. The propeller is a two-blade wooden fixed-pitch. Gross weight is 1,260 lbs, empty weight 750 lbs. Approach speed (T.I.A.S.) is 60 mph, stalling speed 45 mph.
Tests and Research
The engine was ground run after the accident. The propeller was balanced by sawing off a corresponding amount from the other blade. The engine started successfully and ran well and evenly at 2,000 RPM, with throttle short of full RPM. The investigation found no defect or power loss apparent. Control lines showed no loss of continuity.