AF 447 - Flight Crashed

1

Flight AF 44731. May 2009

Jürg Schmid

The Aircraft

A330-200, entered service in 1998

2

Technology

Fly-by-wire technology

Glass cockpit

Flight planning

Communication

Crew and Passengers

3 flight crew, 9 cabin crew, 216 passengers

Part enlargement

Pilot flying, pilot non flying

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The flight

Take off at 2229, weight 232.8t (MTOW 233t)

At 01h 35min 15sec last communication, withATLANTICO controller

The weather

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History of the accident 1

Cruise at FL 350, Mach 0.82, pitch 2.5° ANU, autopilot 2 andauto-thrust engaged

At 2 h 08 min 04, left turn by 12°, speed reduced to Mach0.80

At 2 h 10 min 05, autopilot and auto-thrust disengaged, PF “Ihave the controls”

Hard nose up input, stall warning sounded twice, left PFDand ISIS speed 60 kts

At 2 h 10 min 16, PNF “we’ve lost the speeds then”,“alternate law protections”

Vertical speed reached 7000 ft/min”, dropped to 700 ft/min


At 2 h 10 min 50, PNF tried several times to callCaptain back

At 2 h 10 min 51, stall warning triggered again and was onfor 54 sec

Thrust lever TO/GA, PF maintained nose-up inputs, AOA 6°increasing

Trimmable horizontal stabilizer from 3° to 13° in 1 min, andstayed

At 2 h 11 min 06, speed on ISIS 185 kts, PF continued withnose up inputs

Altitude 38’000 ft, pitch and AOA 16°

5


At 2 h 11 min 45 Captain re-entered the cockpit

In the following sec all speeds became invalid and the stallwarning stopped

Altitude then about 35’000 ft, AOA exceeded 40°, ROD about10’000 ft/min

At 2 h 12 min 02 , PF “I have no more displays”, PNF “wehave no valid indications”

Thrust IDLE detent, pitch down inputs, AOA decreased,speed again valid, stall warning

At 2 h 14 min 28, PF said: “we are going to arrive at levelone hundred”


At 2 h 14 min 28 the recording stopped. Last values

Vertical speed -10’912 ft/min

Ground speed 107 kts

Pitch attitude 16.2 ° ANU

Roll 5.3° left

Heading 270°

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Final Report by BEA

Chapter Conclusion, 51 Findings listed

Several airplanes in same region altered routes to avoidclouds

The copilots have not undertaken any in-flight trainingat high altitude

Neither of the pilots made any reference to stallwarning or buffet.

In less than 1 min after AP disconnect its flightenvelope, inappropriate pilot input

Cause Map – Page 1

Safety Goal Impacted

228 poeple killed

Step 2. Cause Map - Page 1

Airplane brokeapart by impact

with water

Plane unable to maintain

altitude

AND

OR

Cause

Possible Solutions:

Evidence:

CauseEffect

Why?

Start with the Goals (in red) that have been impacted. Read the map to the right by asking Why questions.

Plane nose-up and stall

PropertyGoal

Impacted

Airplane destroyed

Flight control automation not

operable

Crew failed to control flight

manually

AND

Evidence:FDR records

Customer Goal Impacted

Eroded confidence in safety of AF

Production Goal

Impacted


Loss of speed indications

(CAS)


Pitot probes clogged with

ice

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Loss of speed indications

(CAS)

Pitot probes clogged with

ice

Conflicting indications and

alarms

Crew consider stall warnings unreliable ?

Crew decided to keep the

planned route

Crew not aware that the plane at

stall

Pitot probes used vulnerable

to icing

Crew failed to restore aircraft

from stall

Angle of attack not displayed

Meteorological conditions/

thunderstormAND

AND

AND

AND

OR

Evidence:17 cases of icing with Thales AA in 2003 - 2008

Evidence:AB design




Crew failed to control flight

manually



1

2


Task-sharing not defined by

the captain

Absence of the Captain when problem starts

Co-pilots did not brief the Captain

on his return

Left and right controls not

linked

Rest breaks routine in long

flights

AND

AND

AND

Evidence:AB design




Co-pilots not trained for stall at high altitude

Lack of coordination in

the cockpit


from stall

Co-pilots overloaded and

confused

AND

AND

Evidence:Training records


Hard- / Soft-ware problems that

disabled manual control ?

Crew performance

problems

Evidence: Noevidence thusfar to indicate that

OR

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5

4

Co-pilots overloaded and

confused3

4

8


Co-pilots not trained for stall

recovery


from stallCustomer Goal Impacted

Eroded confidence in safety of AF

Production Goal

Impacted

Use of Pitots vulnerable to

icing

AND

Evidence:Training records

Evidence: 17 cases of icing with Thales AA in 2003 - 2008


AF reluctant to replace the

Pitot probes ?

Research by Airbus took too

long time

Avoiding unjustified

costs ?

Evidence: existingCorrespondence/documents

AND / OR

Replacement of the Pitot probes

postponed

Evidence: existingCorrespondence/ documents

Feedback from incidents not

adequate

AND

AND

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1

“A crew can be faced with an unexpected situation leading to a momentary but profound loss of

comprehension. If, in this case, the supposed capacity for initial mastery and then diagnosis is lost, the safety

model is then in ‘common failure mode’.”

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Safety Recommendations

“Shall in no case create a presumption of blame orliability” (EU 996/2010)

Flight recorders, image recorder, FD recorder.

Certification of pitot tubes

Training for manual airplane handling

Additional criteria for access to the role of reliefCaptain

Presence of an angle of attack indicator

Reactions

Operators

Manufacturers

Regulators

Aviation industry actions

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Underlying problems

Basic experience versus highly automated aircraft

Market competition

Rising technical complexity versus individual know how

Aviation – Nuclear – Offshore

Thank you for your attention

AF 447 - Flight Crashed

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