TransAsia Airways GE 235

長文慎入!!

Lets talk about this tragedy, which caused 48 people's life. A simple but fatal mistake!

Comment below!

Credits to Mayday

For you guys to better understand about twin engine.

Taming the twin (full video)

Credits to AOPA Institution.

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要好detail 咁去了解GE235, 就要由AOR 入手.

黑色字係report! 藍色係我ge 諗法同comment!

唔該睇完留下comment~ 我好用心咁去睇report ga~

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Aviation Occurrence Report

4 Feb ,2015

TransAsia Airways Flight GE235

Loss of Control and Crashed into Keelung River

Summary

On February 4, 2015,TransAsia Airways (TNA) flight GE 235, an ATR-GIE Avions de Transport Régional ATR72-212A (ATR72-600) aircraft, registered B-22816, experienced a

loss of control during initial climb and impacted Keelung River, three nautical miles east from its departing runway 10 of Taipei’s Songshan Airport. Forty-three occupants were fatally injured, including three flight crew, one cabin crew, and 39 passengers. The remaining 13 passengers and one cabin crew sustained serious injuries. One passenger received minor

injuries. The aircraft was destroyed by impact forces. The aircraft’s left wing tip collided with a taxi on an overpass before the aircraft entered the river. The taxi driver sustained serious injuries and the only taxi passenger sustained minor injuries. Flight 235 was on an instrument flight rules (IFR)regular public transport service from Songshan to Kinmen.

Summary 無咩好comment

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Findings Related to Probable Causes

Powerplant

1. An intermittent signal discontinuity between the auto feather unit (AFU) number 2 and the torque sensor may have caused the automatic take off power control system (ATPCS):

• Not being armed steadily during takeoff roll;

• Being activated during initial climb which resulted in a complete ATPCS sequence including the engine number 2 autofeathering.

2. The available evidence indicated the intermittent discontinuity between torque sensor and auto feather unit (AFU) number 2 was probably caused by the compromised soldering joints inside the AFU number 2.

之前都講過, ATR 係無AutoThrust; 只有Automatic take off power control system (ATPCS)

ATPCS 係takeoff ge 時候 自動將operating engine UPTRIM (由90% 加到100% full power); 將in-operating engine feather. (上面AOPA 條片有講,如果壞一個Engine, climb performance唔只小左50%; 如果唔feather,可能係小左80% ge power)

所以feather 係好緊要!

而ATR MTOW 22.5T PW127 個 power rating 係2750SHP per engine.

所以single engine 係比較under power(亦因為咁 d ATR pilot 會想盡快shutdown and feather)

(唔feather ge climb rate 最多得300~400ft/min)

GE235 ge scenario 係takeoff ge 時候, engine 2 AFU ge signal 唔stable; ATPCS 無ARM 到.

但係initial climb ge 時侯, 個ATPCS發癲; 佢以為Engine 2 failed 左.所以autofeather 左engine2個propeller. (engine core仲run緊)

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Flight Operations

3. The flight crew did not reject the take off when the automatic take off power control system ARM pushbutton did not light during the initial stages of the takeoff roll.

5J procedure:我地正常每個takeoff, set power ge時侯都要call 'ATPCS Armed' 去confirm ATPCS 係work ge~

Takeoff roll ge 時候,PM 有announce ATPCS NOT armed, 而PF (Captain) decided to continue Takeoff.

正常below 100kt, 有咩壞都會ABORT!

4. TransAsia Airways did not have a clear documented company policy with associated instructions, procedures, and notices to crew for ATR72-600 operations communicating the requirement to reject the take off if the automatic take off power control system did not arm.

其實ATPCS 唔work 都飛得; 要開MEL 跟procedure. 但係正常Takeoff, ATPCS唔work就要abort.

5. Following the uncommanded autofeather of engine number 2, the flight crew failed to perform the documented failure identification procedure before executing any actions. That resulted in pilot flying’s confusion regarding the identification and nature of the actual propulsion system malfunction and he reduced power on the operative engine number 1.

6. The flight crew’s non-compliance with TransAsia Airways ATR72-600 standard operating procedures - Abnormal and Emergency Procedures for an engine flame out at take off resulted in the pilot flying reducing power on and then shutting down the wrong engine.

咁我地每次做sim, engine failure V1 cut 係例牌! 但係今次佢係Propeller Feather(但係仲有N1),

所以佢地confuse左! 熄錯engine!

正常要confirm 左先可以act! 呢個係failure handling ge SOP.

e.g.

PF point at the Power level 2 and announce,"Power lever 2, Confirm?"

PM confirm, then announce,"Confirm!"

Then, PF brings Power lever 2 to idle and announce,"Idle!"

如果佢地follow 個SOP;Confirm 左先, 就唔會shutdown錯engine; 意外係可以避免.

7. The loss of engine power during the initial climb and inappropriate flight control inputs by the pilot flying generated a series of stall warnings, including activation of the stick pusher. The crew did not respond to the stall warnings in a timely and effective manner.

8. The loss of power from both engines was not detected and corrected by the crew in time to restart an engine. The aircraft stalled during the attempted restart at an altitude from which the aircraft could not recover from loss of control.

9. Flight crew coordination, communication, and threat and error management (TEM) were less than effective, and compromised the safety of the flight. Both operating crew members failed to obtain relevant data from each other regarding the status of both engines at

different points in the occurrence sequence. The pilot flying did not appropriately respond to or integrate input from the pilot monitoring.

其實ATR 一無power, 個speed 會 跌得好快! maintain唔到Alt. 佢地engine out 之後仲climb 左300ft; 而speed 就 drop 到得番102kt. 之後就trigger 左個stick shaker 同stick pusher. At that moment, Both engine shutoff; @1630ft @102kt stick shaker activated, 根本無野可以做到去救機.

因為個P&W 127 engine restart 最快都要2分鐘.

Report 話佢地有attempt過restart(restart at 500ft); 但係太遲~

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Findings Related to Risk

Powerplant

1. The engine manufacturer attempted to control intermittent continuity failures of the auto feather unit (AFU) by introducing a recommended inspection service bulletin at 12,000 flight hours to address aging issues. The two AFU failures at 1,624 flight hours and 1,206 flight

hours show that causes of intermittent continuity failures of the AFU were not only related to aging but also to other previously undiscovered issues and that the inspection service bulletin viii implemented by the engine manufacturer to address this issue before

the occurrence was not sufficiently effective. The engine manufacturer has issued a modification addressing the specific finding of this investigation. This new modification is currently implemented in all new production engines, and another service bulletin is available for retrofit.

個AFU 係有issue! 之前5J 都有similar event. Uncommanded Autofeather. 有機會講下.

Flight Operations

2. Pilot flying’s decision to disconnect the autopilot shortly after the first master warning increased the pilot flying’s subsequent workload and reduced his capacity to assess and cope with the emergency situation.

-600 個AP 比-500 好; -600 Autopilot有rudder trim; 所以易d manage.

-500 個AP 無rudder trim; 如果未trim 好; 個AP 會disengage!

可能個Captain; 未慣飛-600, 唔信個AP.

Airline Safety Management

5. TransAsia Airways (TNA) did not use widely available crew resource management (CRM) guidelines to develop, implement, reinforce, and assess the effectiveness of their flight crew CRM training program.

6. While the TransAsia Airways (TNA) ATR72-600 differences training program was consistent with the European Aviation Safety Agency ATR72 operational evaluation board report and compliant from a Civil Aeronautics Administration regulatory perspective, it may not have been sufficient to ensure that TNA flight crews were competent to operate the ATR72-600 under all normal procedures and a set of abnormal conditions.

-500同-600 雖然係同type;但係要cross type 都唔容易~

CRM 都係個Big factor.

Regulatory Oversight

9. The Civil Aeronautics Administration’s (CAA) oversight of flight crew training, including crew resource management (CRM) training, is in need of improvement.

10. The systemic TransAsia Airways (TNA) flight crew non-compliances with standard operating procedures identified in previous investigations, including GE 222, remained unaddressed at the time of the GE235 occurrence. Although the Civil Aeronautics Administration (CAA) had conducted a special audit after the GE 222 accident which

identified the standard operating procedures compliance issue, the CAA did not ensured that TNA responded to previously identified systemic safety issues in a timely manner to minimize the potential risk.

Training Department 同quality department 好重要.

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Other Findings

4. Flight crew transferred from conventional flight instruments to a more advanced avionic suite with primary flight display, the visual pattern and information picked up by the crew in an emergency situation may not be retrieved at the same location with the same display.

因為-500 係analog; -600係glass. 所以佢地唔familiar.

講住咁多先~反應好 夠Comment 再講埋CRM (2個Captains = safer? ge 迷思)

如果想睇full report, link: https://bit.ly/235report