1

Cougar Flight 91:Human Factors

CASI-AEROMontréal, Quebec

26 April 2011

Wendy Tadros, TSB Chair

Introduction

2

Outline

• About the TSB• History of Flight 91• Causes• Key Human Factors

– Flight Manuals / Emergency Procedures– Crew Knowledge– Crew Resource Management

• Residual Risks• Recommendations

3

On Scene

4

About the TSB

5

Overview

6

The Whole Story

7

8

9

A complex equationof 16 causes

and contributing factors

Key Human Factors

• Ditching and Risk of Capsizing

• Flight Manual and Emergency Procedures

10

Key Human Factors (cont’d)

• Crew Training / Knowledge• Vibrations• Oil Temperature (“wet bulb”)

• Oil Pressure as Secondary Indicator

11

Crew Resource Management

The Department of Transport require commercial air operators to provide contemporary crew resource management (CRM) training for Canadian Aviation Regulations (CARs) subpart 703 air taxi and CARs subpart 704 commuter pilots.

A09-02

12

Cougar CRM

13

Maintenance ProceduresAustralia, July 2008

• S-92 loses oil from main gearbox.

• Cockpit warnings, crew reaction very similar to Flight 91 accident.

• Safe landing 7 minutes later.

• Pilot: lower and slower

14

Residual Risks (Certification)

• Main gearbox failed after 11 minutes during test.

• Rule includes clause that test not required if failure shown to be extremely remote.

• Oil cooler most likely failure route. Bypass valve added. Oil filter bowl and its fasteners not assessed.

• Today? There’s still only 11 minutes.

15

16

Four Recommendations

1. All S-92 helicopters to meet a 30-minuterun dry

2. The FAA to decide if even 30 minutesis enough time

3. Transport Canada to restrict flights wherethe helicopter’s flotation system is not up to the task for the sea conditions that day

4. Emergency breathing equipment on flights where survival suits are required

17

Summary

18

Questions?

19

20