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!!