Investigation Kish Air Flight 7170

1 investigation

1.1 cvr analysis
1.2 fdr analysis
1.3 weather analysis
1.4 eyewitness account
1.5 final report

investigation

the remains of kish air flight 7170, 1 year after crash.

the investigation conducted emirates general civil aviation authority, several investigation team outside, including iran civil aviation organization (cao) (as state of operator/registry), dutch transport safety board (as manufacturer of aircraft), canadian transportation safety board (as engine manufacturer), uk air accidents investigation branch (as manufacturer of propellers) , national transportation safety board (as manufacturer of aircraft s skid control unit).

based on aircraft s logbook, there no recorded defects or unscheduled maintenance since overhaul. aircraft technical logbooks indicated there had been no scheduled or unscheduled maintenance conducted on aircraft propeller components.

the cockpit voice recorder , digital flight data recorder retrieved relatively undamaged tail section of aircraft in condition. presented bureau enquetes accidents (bea) in le bourget, france on 16 february 2004 extraction of dfdr data , cvr transcription.

cvr analysis

from cvr, captain heard hand on control of aircraft first officer during descent 2500 ft , tell first officer first officer’s flight. first officer not expecting , not accept willingly not confident of ability conduct vor/dme approach sharjah. first officer heard doesn’t have same experience captain conduct approach , captain insists. captain, in attempt boost first officer’s confidence, heard encourage him , continued assist him during conduct of approach. generates discussion , first officer continues fly captain giving advice on inbound track capture , approach profile. there inconsistency exchange first officer had on 4000 flight hours, of 600 hours on f27 mk.050 aircraft , had 2400 hours pilot in command on large turbo-prop aircraft (lockheed hercules c-130).

the cvr indicated captain took on control of aircraft , intended hand on control again first officer once aircraft on correct profile landing. first officer discusses limiting altitudes , dme distances observed. on reaching 4 nm point dme first officer heard disconnect autopilot , shortly afterwards call flap 10 landing gear down . captain states has control. few seconds later propeller(s) rpm noise heard increasing.

fdr analysis

the thrust lever of fokker 50

the fdr parameter low propeller pitch lights indicate left propeller entered ground control range 1 sec prior right propeller, yet propeller rpm parameters indicated both propellers moved simultaneously ground control range. engine, aircraft , propeller manufacturers in agreement propeller behaviour in ground control range during flight unpredictable. however, analysis of dfdr data, there general consensus propeller behaviour.

on selection of power levers ground control range, propeller pitch changes resulted in decrease of lift on wing , turbulent low speed airflow on tail plane , elevator. coupled other aerodynamic moments associated lift/drag , thrust/weight coupling, aircraft pitched down , remained in nose low attitude. aircraft commenced roll left due asymmetric drag effects of different propeller pitch angles. left propeller went full reverse whilst right propeller remained in positive pitch within ground control range.

weather analysis

investigators stated there general forecast of weakening high pressure gradient covering area no low level instability expected. actual weather @ time of accident fine bright sunlight, hazy light , variable winds. investigators @ scene reported clear skies , light variable winds conditions stated in meteorological reports. photographs taken 2 km away , shortly after accident occurred show smoke rising vertically without wind effect. there no reports of turbulence prior accident , helicopter crews operating accident site reporting smooth flying conditions.

eyewitness account

two pilots of aircraft waiting @ hold point runway 12 witnessed crash. pilots had been told taxi , hold flight 7170 , reason watching flight land. told investigators aircraft flying when nose pitched down 60-degree angle , spiraled left. investigators learnt witnesses nothing had come off aircraft beforehand, ruling out structural failure.

final report

the accident investigated general civil aviation authority. investigation crash revealed pilots had accidentally selected propellers reverse thrust while still in air. caused loss of control , subsequent crash. propellers can move ground control range if power levers physically moved past primary stop pilot. considering several contributing factors:

by insisting first officer fly final approach, pilot in command created environment, led breakdown of crew resource management processes, non observance of operator’s standard operating procedures , resultant excessive high approach speed.
an attempt rectify excessive high approach speed resulted in non compliance standard operating procedures , movement of power levers below flight idle.
the unmodified version of skid control unit failed provide adequate protection @ time of event.




^ cite error: named reference icao invoked never defined (see page).