Brian Roland

meetings.waea.org

Brian Roland

A Reality about Reliability

Brian Roland

Project Manager, Interiors Engineering

Continental Airlines

February 13, 2003


A Reality about Reliability

US airlines are required to have a

Reliability Program in accordance to FAR

121.373:

Continuing Analysis and Surveillance.

(a) Each certificate holder shall establish and maintain

a system for the continuing analysis and surveillance of

the performance and effectiveness of its inspection

program and the program covering other maintenance,

preventive maintenance, and alterations and for the

correction of any deficiency in those programs….


Reliability versus Availability

• Reliability

– Useful in evaluating component performance

and maintenance requirements

• Availability (ARINC 628 Part 8)

– Useful for evaluating a systems effectiveness at

providing the intended service to the passenger


What is Reliability?

By technical definition:

The probability that an item will perform a

required function without failure under

stated conditions for a stated period of time


Operational Indicators

• Inverse of failure rate (failures/hour)

• MTBUR - Mean Time Between Unscheduled

Removals

– Total hours / number of unscheduled removals

– Removal is an interruption of continual usage

• MTBF - Mean Time Between Failure

– Confirmed failure


Longevity Indicators

• MTTF - Mean Time To Failure

– Average time a unit remains serviceable until

failure


IFE Reliability

• Focus is on IFE components rather than

entire system performance

– Does the component work and for how long?

• IFE is made up of components chained in a

series - any break in the chain can be critical


Reliability over Availability

• At Continental, availability is rarely used to

measure IFE performance

• Even with poor component reliability,

availability can be 100%


Example

Scenario for Tape Player

Time span

30 days

Fleet size

71 aircraft

Number of units/aircraft 3

Number of unscheduled removals 39


Calculating Usage

Aircraft Utilization 3 flight-segments per day

4 hours per segment

Usage

= 71 aircraft X 3 flight-segments/day X 30 days

= 6390 aircraft flight-segments

X 3 components/aircraft

= 19,170 component flight-segments

X 4 hours per segment

= 76,680 component flight-hours


MTBUR Result

• In terms of Reliability for 30-day period:

MTBUR =

76,680 component flight-hours

39 unscheduled removals

= 1966 Hours

• MTBF Target is 4500 hours


But in Terms of Availability…

• Result = 100% because of redundancies

• Source Availability (ARINC 628P8)

“Sources are only to be considered unavailable

if a failure impacts the ability of a passenger to

use the IFE system for its intended function.”


Availability Flying at 100%

• Redundant components

• Alternate programming

• Manual play overriding automatic mode

• Open seats with operative in-seat IFE


The Burdens of Breakdowns

• Disruption and/or degradation of inflight

service

• Intervention required by flight crews

• Maintenance costs and spares

• Delays

• Loss of revenue and loyalty

• Customer compensation


IFE Reliability Management

Concerted effort between Supplier and Airline

– Maintenance reporting failures

– Reliability analyzing failure modes and trends

– Engineering determining root causes and

implementing corrective action plans

– Purchasing coordinating repair and action plan


Collecting Reliability Data

Failure reporting is key:

– Aircraft log pages and data collection

• Details of conditions experienced is critical

– Component tear down reports

– Communication between supplier and airline


Measuring Reliability

Invokes various statistical data analysis to

assemble a proper perspective of reliability

– Trend analysis

– Growth analysis

– Failure mode analysis

– Times-to-failure analysis


IFE Problem Children

• Tape Player

• Monitor

• Passenger Control Unit (PCU)

• System Control Unit (SCU)

• Audio


Log Page Analysis

120

737 NG IFE Log Pages

30%

100

# L/P, (737NG, TTL 480)

25%

Nbr of Log Pages

80

60

40

% L/P (737NG)

20%

15%

10%

Percentage of Log

Pages

20

5%

0

TAPE PLR MONITOR SCU PCU SEB PRAM ARU MUX

# L/P, (737NG, TTL 480) 119 98 69 95 22 9 8 5

% L/P (737NG) 25% 20% 14% 20% 5% 2% 2% 1%

Category

0%


Trend Analysis

737NG TAPE PLAYER

MTBUR or MTBF, Hours

20000

18000

16000

14000

12000

10000

8000

6000

4000

2000

0

12 month MTBF

12 month MTBUR

12 month NTF %

100

80

60

40

20

0

5/99

7/99

9/99

11/99

1/00

3/00

5/00

7/00

9/00

11/00

01/01

03/01

05/01

07/01

09/01

11/01

01/02

03/02

05/02

07/02

09/02

11/02

NFF, %


Failure Mode Analysis

50%

Tape Player Failure Type Comparison

Percent of Failures

45%

40%

35%

30%

25%

20%

15%

10%

5%

06-12/00 01-05/01

0%

INOP TAPE STUCK DAMAGE TAPES BAD PICTURE

06-12/00 41% 20% 6% 5%

01-05/01 32% 32% 13% 4%

Failure Type


Typical Tape Path in Player


Demise of the Hi-8:

Repair Breakdown

NFF/Cln (10 REP ORDERS)

REMOVE BAD TAPE (29)

Tear Down N/A (13)

Cassette Components Related (69)

Eating Tape / Tape Stuck in / Tape Jam

NFF/Cln (10 REP

ORDERS)

8%

REMOVE BAD TAPE (29)

24%

Cassette Components

Related (69)

57%

Tear Down N/A (13)

11%


Failure Analysis Summary

• Determine the root cause of failure/removal

• Analyze repair breakdowns

• Develop fault tree

• Identify failure trends

– Mechanical wear, deterioration, damage

– Software fault

– Environment – heat, humidity, contaminants


The VCC Environment


Improving IFE Reliability

• Identify root cause of failures and implement fix

• Increase spares and allocation

• Modify software and/or hardware

• Implement proper maintenance & equipment

cleaning programs

• Train personnel on better handling

• Improve environment around IFE equipment


A Reality about Reliability

• Reliability is a valuable measurement of IFE

performance

– Requires detailed failure reporting, complex data

analysis, and an effective corrective action program

• Redundancies allow availability to run at 100%

• Design better “fly-to-fail” components while

keeping cost of ownership down


THANKS!!

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