Dutch Safety Safety Board: Safety Alert to Boeing:
Recommend to review Fligth Manual B737: if radio altimeters are inop, autothrottles and autopilot must not be engaged;
* 9 casualties;
* 80 wounded, 28 still in hospital;
* TK 1951 ETA 10.40
* No problems until last moment;
* 3 qualified pilots in cockpit;
* 1st officer flying the aircraft;
* TK1951 received landing clearance, no delay in approach, direct approach;
* Autopliot engaged during approach;
* DFDR and CVR in good condition;
* at 1950 ft, LH radio altimeter step change read out from 1950 ft to -8ft;
* this faulty altitude was also reported to autothrottle;
* CVR: crew saw altimeter discrepancy;
* Crew did not see this discrepancy as problem, and lowered gear as gear warning was activated due to -8 ft radio alt;
* As a result, autothrottle went into retard mode at 1950 ft rather than 50 ft due to faulty radio altimeter read out;
* Aircraft slowed to stall speed;
* Aircraft flight controls [autothrottles] thought airplane was above runway and went into "flare mode";
* At 450 ft stall warning /stick shaher activated;
* power was increased immediately [!] [TOGA?], but power increase was too late to continue flight;
* identical problem with LH radio altimeter happened twice before on this airplane in last eight flights;
* that data was still on DFDR, as it had 25 hrs upto crach of recorded information;
* Landing gear and engines broke off at impact as designed;
* due to high power setting engines flew forward by 250m at impact separation;
* investigation will now focus on radio altimeter, and relation/logic with autothrottle system;
* runway was not [very well] visable to crew;
* Dutch Safety Board will lead investigation;
* Several other parties will support investigation [NTSB, Boeing, CFM internaional, Turkish authorities, ;
* Good words for justice department, especially in isolating area around airplane;
* Safety Board and Jutice Department back on same frequency;
* Main objective of investigation is fact finding and improve safety;
* Justice department will limited access to data, to protect "whistleblowers";
* radio altimeter fault is only technical fault found so far;
* No indications of ATC faults;
* No indications of [wake-]turbulence;
* Too early to tell if crew made mistakes;
* All members of invetsigation team are on same line of thinking
* Not yet known where the 2 previous occurances of LH radio Alt happened
* LH radio Alt not considered flight critical component, as function can be taken over manually by crew;
* No conclusions on TK maintenance activities and procedures;
* Aircraft will be recovered this week;
Recommend to review Fligth Manual B737: if radio altimeters are inop, autothrottles and autopilot must not be engaged;
* 9 casualties;
* 80 wounded, 28 still in hospital;
* TK 1951 ETA 10.40
* No problems until last moment;
* 3 qualified pilots in cockpit;
* 1st officer flying the aircraft;
* TK1951 received landing clearance, no delay in approach, direct approach;
* Autopliot engaged during approach;
* DFDR and CVR in good condition;
* at 1950 ft, LH radio altimeter step change read out from 1950 ft to -8ft;
* this faulty altitude was also reported to autothrottle;
* CVR: crew saw altimeter discrepancy;
* Crew did not see this discrepancy as problem, and lowered gear as gear warning was activated due to -8 ft radio alt;
* As a result, autothrottle went into retard mode at 1950 ft rather than 50 ft due to faulty radio altimeter read out;
* Aircraft slowed to stall speed;
* Aircraft flight controls [autothrottles] thought airplane was above runway and went into "flare mode";
* At 450 ft stall warning /stick shaher activated;
* power was increased immediately [!] [TOGA?], but power increase was too late to continue flight;
* identical problem with LH radio altimeter happened twice before on this airplane in last eight flights;
* that data was still on DFDR, as it had 25 hrs upto crach of recorded information;
* Landing gear and engines broke off at impact as designed;
* due to high power setting engines flew forward by 250m at impact separation;
* investigation will now focus on radio altimeter, and relation/logic with autothrottle system;
* runway was not [very well] visable to crew;
* Dutch Safety Board will lead investigation;
* Several other parties will support investigation [NTSB, Boeing, CFM internaional, Turkish authorities, ;
* Good words for justice department, especially in isolating area around airplane;
* Safety Board and Jutice Department back on same frequency;
* Main objective of investigation is fact finding and improve safety;
* Justice department will limited access to data, to protect "whistleblowers";
* radio altimeter fault is only technical fault found so far;
* No indications of ATC faults;
* No indications of [wake-]turbulence;
* Too early to tell if crew made mistakes;
* All members of invetsigation team are on same line of thinking
* Not yet known where the 2 previous occurances of LH radio Alt happened
* LH radio Alt not considered flight critical component, as function can be taken over manually by crew;
* No conclusions on TK maintenance activities and procedures;
* Aircraft will be recovered this week;
