A Naysa/Binter Canarias Avions de Transport Regional ATR-72-500, registration EC-LFA performing flight NT-169 from Las Palmas,CI to Tenerife Norte,CI (Spain) with 51 passengers and 4 crew, landed on Tenerife's wet runway 12 at 18:50L (18:50Z) but veered left off the runway and came to a stop approximately in front of the apron 1300 meters down the runway with the nose gear on soft ground off the runway. There were no injuries, the aircraft received minor damage.
The airline confirmed the aircraft was involved in an incident upon arrival at Los Rodeos Airport (Tenerife Norte), there were no injuries and no substantial damage.
On Dec 16th 2013 the French BEA quoted Spanish Authorities rating the occurrence an accident due to damage to the nose gear.
On Jan 2nd 2014 Spain's CIAIAC reported that the aircraft touched down with both its main gear legs on runway 12, the main gear bounced off the runway again, the aircraft touched down a second time with the nose gear first, bounced off a second time and then settled on the runway. The CIAIAC stated the aircraft sustained minor damage to the nose landing gear, additional information is being awaited.
On Apr 4th 2016 the CIAIAC released their final report concluding the probable cause of the incident was:
The incident was caused due to the aircraft making a hard landing at an incorrect attitude. Contributing to this was a faulty perception of distance due to the optical illusions generated by the adverse meteorological conditions that prevailed at the time of the landing.
The CIAIAC reported it was raining hard with reduced visibility at the time of landing, the windshield wipers were operating at maximum speed. The approach was normal until immediately prior to touch down.
The CIAIAC analysed: "Both pilots stated they had misjudged the distance to the runway and that the runway lights were very bright. While bright runway lights can increase visibility and facilitate an approach in low visibility conditions, as an aircraft approaches the runway and prepares for landing, they could lead to erroneous perceptions. The prevailing weather conditions at the time of landing were favorable to the appearance of optical illusions caused by flying in reduced visibility, be it due to fog or rain, and leading to a sensation of flying higher, with the pilot’s reaction tending to be to fly lower. Specifically, the black hole illusion, which occurs during nighttime landings when there are no outside references except for the runway lights, makes the runway appear higher, resulting in the pilot lowering the nose. Similarly, the sudden disappearance of visual references due to fog or mist when the pilot had the runway in sight from a long distance can lead the pilot to think that the nose is high, thus prompting the pilot to correct the situation by lowering the nose. The rain on the windshield can also cause effects that distort distance perception. The geographic condition of the runway, namely its positive gradient, could induce the sensation of flying higher, prompting the pilot to fly lower. Although the pilots stated that they did not hear the radio altimeter callouts, the sounds recorded by the CVR indicate that the EGPWS issued the relevant callouts. The findings of the inspection conducted afterwards also showed that there were no faults in the system."
The CIAIAC continued analysis: "According to the FDR data, the aircraft suddenly changed from a positive (+3) to a negative (–4) pitch angle in just 6 seconds at an altitude AGL of 800 ft. The pitch angle then remained negative (–5) until an altitude AGL of 23 ft. These values do not represent an ideal attitude for the aircraft in the moments immediately prior to landing. This situation could be explained by an improper depth perception and by the crew’s inability to hear the GPWS callouts. The FDR data confirm that the crew made a stabilized approach; however, in light of the wind conditions reported on final, the captain decided to increase their speed by the maximum wind factor allowed (15 kt). Their target Vapp speed was thus 123 kias. Although the speed recorded prior to landing was 130 kt, this does not violate the stabilization requirements contained in the Operations Manual to maintain speed between Vapp and Vapp+10 when flying over the runway threshold. This increased speed, however, did favor lowering their pitch angle, which increased the risk that the initial contact with the runway would be made with the nose wheel in the event of a late flare. The FDR data also indicate that the initial contact with the runway was with the nose wheel at a vertical acceleration of 2.41 g. This was followed by three further touchdowns with the main gear before the aircraft stopped, the first of these leading to the maximum recorded vertical acceleration value of 2.6 g. These data are consistent with the breaking of the nose wheel leg and the subsequent loss of directional control, as well as with the damage to the left main gear. Once the aircraft’s directional control was lost, its own inertia caused it to depart the runway. "
