Asia

Loss of control due to icing conditions. It was determined that the aircraft was flying in icy conditions for a long period of time during an artificial rainfall operation and the wings and propellers became seriously iced up. The aircraft was unable to effectively control the risk of icing, which resulted in the aircraft losing speed and entering a spin, eventually crashing to the ground and catching fire. Based on the casualties and damage to the aircraft, the incident constituted a major general aviation accident of aircraft crew origin. The investigation also found that the aircraft had been modified in such a way that the relevant data was not available and that the crew did not handle the spin properly.

The following contributing factors were identified:
• The corrective maintenance processes of the A/T problem were unable to identify the friction or binding within the mechanical system of the thrust lever and resulted in the prolonged and unresolved of the A/T problem.
• The right thrust lever did not reduce when required by the A/P to obtain selected rate of climb and aircraft speed due to the friction or binding within the mechanical system, as a result, the left thrust lever compensated by moving further backward which resulted in thrust asymmetry.
• The delayed CTSM activation to disengage the A/T system during the thrust asymmetry event due to the undervalued spoiler angle position input resulted in greater power asymmetry.
• The automation complacency and confirmation bias might have led to a decrease in active monitoring which resulted in the thrust lever asymmetry and deviation of the flight path were not being monitored.
• The aircraft rolled to the left instead of to the right as intended while the control wheel deflected to the right and inadequate monitoring of the EADI might have created assumption that the aircraft was rolling excessively to the right which resulted in an action that was contrary in restoring the aircraft to safe flight parameters.
• The absence of the guidance of the national standard for the UPRT, may have contributed to the training program not being adequately implemented to ensure that pilots have enough knowledge to prevent and recover of an upset condition effectively and timely.

Failure of the high pressure compressor disk on the engine n°2 during the takeoff procedure.

The probable cause of the accident was the non adherence to SOP by the PF, wherein, he continued an unstabilized approach and landed beyond the touchdown zone, half way down the runway, in spite of ‘Go Around’ call by PM which warranted a mandatory ‘Go Around’ and the failure of the PM to take over controls and execute a ‘Go Around’.

The following contributing factors were identitified:

The investigation team is of the opinion that the role of systemic failures as a contributory factor cannot be overlooked in this accident. A large number of similar accidents/incidents that have continued to take place, more so in AIXL, reinforce existing systemic failures within the aviation sector. These usually occur due to prevailing safety culture that give rise to errors, mistakes and violation of routine tasks performed by people operating within the system. Hence, the contributory factors enumerated below include both the immediate causes and the deeper or systemic causes.

(i) The actions and decisions of the PIC were steered by a misplaced motivation to land back at Kozhikode to operate next day morning flight AXB 1373. The unavailability of sufficient number of Captains at Kozhikode was the result of faulty AIXL HR policy which does not take into account operational requirement while assigning permanent base to its Captains. There was only 01 Captain against 26 First Officers on the posted strength at Kozhikode.

(ii) The PIC had vast experience of landing at Kozhikode under similar weather conditions. This experience might have led to over confidence leading to complacency and a state of reduced conscious attention that would have seriously affected his actions, decision making as well as CRM.

(iii) The PIC was taking multiple un-prescribed anti-diabetic drugs that could have probably caused subtle cognitive deficits due to mild hypoglycaemia which probably contributed to errors in complex decision making as well as susceptibility to perceptual errors.

(iv) The possibility of visual illusions causing errors in distance and depth perception (like black hole approach and up-sloping runway) cannot be ruled out due to degraded visual cues of orientation due to low visibility and suboptimal performance of the PIC’s windshield wiper in rain.

(v) Poor CRM was a major contributory factor in this crash. As a consequence of lack of assertiveness and the steep authority gradient in the cockpit, the First Officer did not take over the controls in spite of being well aware of the grave situation. The lack of effective CRM training of AIXL resulted in poor CRM and steep cockpit gradient.

(vi) AIXL policies of upper level management have led to a lack of supervision in training, operations and safety practices, resulting in deficiencies at various levels causing repeated human error accidents in AIXL

(vii) The AIXL pilot training program lacked effectiveness and did not impart the requisite skills for performance enhancement. One of the drawbacks in training was inadequate maintenance and lack of periodic system upgrades of the simulator. Frequently recurring major snags resulted in negative training. Further, pilots were often not checked for all the mandatory flying exercises during simulator check sessions by the Examiners.

(viii) The non availability of OPT made it very difficult for the pilots to quickly calculate accurate landing data in the adverse weather conditions. The quick and accurate calculations would have helped the pilots to foresee the extremely low margin for error, enabling them to opt for other safer alternative.

(ix) The scrutiny of Tech Logs and Maintenance Record showed evidence of nonstandard practice of reporting of certain snags through verbal briefing rather than in writing. There was no entry of windshield wiper snag in the Tech log of VT-AXH. Though it could not be verified, but a verbal briefing regarding this issue is highly probable.

(x) The DATCO changed the runway in use in a hurry to accommodate the departure of AIC 425 without understanding the repercussions on recovery of AXB 1344 in tail winds on a wet runway in rain. He did not caution AXB 1344 of prevailing strong tail winds and also did not convey the updated QNH settings.

(xi) Accuracy of reported surface winds for runway 10 was affected by installation of wind sensor in contravention to the laid down criteria in CAR. This was aggravated by frequent breakdown due to poor maintenance.

(xii) The Tower Met Officer (TMO) was not available in the ATC tower at the time of the accident. The airfield was under two concurrent weather warnings and it is mandatory for the TMO to be present to update and inform the fast changing weather variations to enhance air safety. During adverse weather conditions the presence of the TMO in the ATC tower was even more critical.

(xiii) The AAI has managed to fulfil ICAO and DGCA certification requirements at Kozhikode aerodrome for certain critical areas like RESA, runway lights and approach lights. Each of these, in isolation fulfils the safety criteria however, when considered in totality, this left the aircrew of AXB 1344 with little or no margin for error. Although not directly contributory to the accident causation, availability of runway centreline lights would have certainly enhanced the spatial orientation of the PIC.

(xiv) The absence of a detailed proactive policy and clear cut guidelines by the Regulator on monitoring of Long Landings at the time of the accident was another contributory factor in such runway overrun accidents. Long Landing has been major factor in various accidents and incidents involving runway excursion since 2010 and has not been addressed in CAR Section 5, Series F, Part II.

(xv) DGCA did not comprehensively revise CAR Section 5, Series F, Part II Issue I, dated 30 Sep 99 (Rev. on 26 Jul 2017) on ‘Monitoring of DFDR/QAR/PMR Data for Accident/Incident Prevention’ to address the recommendations of the COI of 2010 AIXL Managlore Crash regarding the exceedance limits, resulting in the persisting ambiguities in this matter.

(xvi) DFDR data monitoring for prevention of accidents/incidents is done by AIXL. However 100% DFDR monitoring is not being done, in spite of the provisions laid down in the relevant CAR and repeated audit observations by DGCA. DFDR data monitoring is the most effective tool to identify exceedance and provide suitable corrective training in order to prevent runway accidents like the crash of AXB 1344. However, ATR submitted by AIXL on the said findings were accepted by DGCA year after year without ascertaining its implementation or giving due importance to its adverse implications.

The accident with the An-2 RA-71276 aircraft occurred as a result of a collision with a mountain at an altitude of 2,780 metres above sea level perpendicular to the direction of the ridge with its minimum height of 2,960 metres conditions of limited visibility and the closure of mountain tops by clouds.
The following contributing factors were identified:
- The crew took the decision to perform a flight over a mountainous area with predicted closure of the mountains by clouds and unfavorable wind conditions,
- The crew took the decision to return to the landing site through the mountain range along an unexplored and previously unused route,
- Operational fatigue of the crew due to the significant duration of working hours on the day of the accident (more than 12 hours),
- The airplane falling under the influence of descending air currents on the leeward side of a mountain slope.