EWIS Training

(1)

EWIS

Electrical Wiring Interconnect System

Not Just Another Acronym!

Technical Committee

(2)

What is EWIS?

• All wiring related components connecting

LRU’s such as:

– Wiring – Cannon Plugs – Modular Blocks – Clamps – Terminal Strips – Etc.

(3)

Why the concerns about EWIS?

• History

– NTSB, following the TWA 800 accident, determined that wiring inside a fuel tank

developed a short causing an explosion which downed the aircraft.

– Vice Presidential Committee – Gore –

Commissioned detailed study be performed on the health of aircraft wiring in regards to aging of an aircraft.

(4)

Why the concerns about EWIS?

History (cont.)

– The FAA in conjunction with regulatory agencies worldwide and industry developed a focus group to study the potential problem.

• ATSRAC (Aging Transport Systems Rulemaking Advisory Committee)

–Originally formed to perform non-intrusive, intrusive inspections and develop

recommendations to the FAA for Large Transport Aircraft. (ADs, SFAR)

• After the Payne Stewart incident, NTSB

recommended that all Transport Aircraft be included in ATSRAC study - STA

(5)

ATSRAC – HWG10 - STA

WIRING EVALUATIONS

- Summary

• 39 privately owned in-service a/c

– No Safety of Flight Concern

– 2256 discrepancies

– 73 of them are considered as significant*

items

*

Significant items need to be rectified/repaired for

continued airworthiness throughout aircraft operational life

(6)

ATSRAC - STA

WIRING EVALUATIONS

(Cont'd)

• No aging issue specific to wire insulation and

conductor were detected

• 29 % of discrepancies are inadequate clearance

with structure, racks, equipments

• 43 % of discrepancies are bad clamp

conditionning/sizing/spacing

• 68 % of significant items are due to inadequate

clearance or bad clamp conditionning: sizing /

spacing

.

(7)

Aircraft Type

Findings Summary AC Model A AC Model B AC Model C AC Model D AC Model E AC Model F AC Model G AC Model H Summary

Number of Aircraft Inspected 5 5 5 5 4 5 5 5 39

% of the Model Fleet 5.90% 2.90% 0.61% 0.90% 2.10% 2.10% 1.05% 0.80% 0.6% to 6%

Age Range 19 to21 11 to 24 10 to 18 18 to 25 11 to 12 20 to 30 12 to 15 11 to 32 10 to 32

Hour Range 4785 to 7835 4130 to 12001 3258 to 8413 7223 to 12408 4130 to 8083 8770 to 17389 4271 to 5904 3572 to 13014 3258 to 17389

Landing (Cycles) Range 4846 to 5684 3473 to 8558 2682 to 5692 5709 to 9873 2746 to 7498 4843 to 8500 2638 to 3389 3187 to 13252 2638 to 13252

Inspections Performed By WG & OEM WG & OEM WG & OEM WG & OEM WG & OEM WG & OEM OEM WG & OEM WG & OEM

0

73 1.9

2256 58

Evaluation Findings % to Specific Model Totals by Appendix A Categories:

Connectors 3.20% 1.90% 5.40% 3.30% 1.70% 1.80% 0% 2.30% 2.75% Terminations 2.30% 0.60% 0.30% 6.70% 0 0.40% 0% 5.50% 1.99% Installations (General) 80% 79.50% 87% 87% 90.50% 86.40% 97.40% 80.70% 84.53% Wiring Condition 14.40% 18% 7.30% 2.90% 7.80% 11.40% 2.60% 11.50% 10.73% Significant Items % of Significant Items (73 Items) to All Model (2256

Items) Evaluation Findings 3.24%

Findings per AC (Avg.) Immediate Fleet Wide Safety

Total Findings Significant Items Significant Items per AC (Avg.)

(8)

Damaged Clamp

Zone: 310 Aft equipment compartment below APU

(9)

(10)

Installation inverted Teflon shim

(11)

Disabled system connectors – pulled from rack Tied to environmental system duct

(12)

(13)

(14)

Improperly

Installed Clamp (pinching wire) Zone: 140 Under floor area above wing box

(15)

(16)

Bend Radius

Zone: 220 Flight compartment above floor behind circuit breaker panel (copilot’s feet)

(17)

Bend radius

(18)

(19)

(20)

Inadequate Clearance to Structure

Zone: 114/115 Flight compartment under floor bottom of fuselage

(21)

Damaged Conduit _{Zone: 143/144 Main landing} gear wheel well

(22)

Outer Jacket of

Power Cable Pulled Back Wires Exposed

(23)

Improper Repair

(24)

Debris on Power Wires (Metal Shavings)

(25)

Contaminated Wires

Zone: 250 Cabin area above floor near luggage compartment door

(26)

ATSRAC – HWG10

General Comments

-

From a/c evaluations

• Aircraft in good overall condition

• Reasons of Discrepancies

– Wiring Repair

• Training Issues

• Lack of use of OAM Standard Practice Manuals

– Routing of Modification Wiring

• Training Issues

• Lack of use of Industry Standard Guidelines (AC 43.13) and OAM Standard Practice Manuals

(27)

ATSRAC – HWG10

General Comments

(cont'd)

Clamping and Structural Contact

– Training Issues

– Instructions for Continued Airworthiness Issues

• “Protect, Clean as you go” philosophy

– Training Issue

– ICA – possible no mention

• Industry cultural concerns

(28)

Aircraft Maintenance Program Philosophy

– STA = OEMs Develops and Maintains

Maintenance Programs – FAA approves Chapter 4/5 and accepts Mx Manuals (ICAs)

• Owner/Operator typically follows OEM Recommendations

– STA = Owner/Operator to # Aircraft - 1 to 1.4

• Each Aircraft is Very Unique as each owner

• Avionics Packages vary from aircraft to aircraft • Corporate Interiors and the associated wiring vary

from aircraft to aircraft

(29)

ATSRAC – HWG10

Organizational Differences

– STA = Smaller Organizations within each Department

• Dispatch • Flight

• Maintenance (35%)

– STA Owner/Operators tend to be more interdependent with TC and STC Holders

(30)

NBAA Operator Demographics

669 2358 314 362 588 237 0 500 1000 1500 2000 2500 3000 3500 1 2 >2 W /O MX W ith MX Operators Aircraft Operated

(31)

ATSRAC – HWG10

Lessons Learned

• Before April of 2002 the Majority of the

Working Group was not Aware of EWIS

-Concepts

• Based on the review of:

– Aircraft Evaluations

– Service History/ADs

– Intrusive Inspection Report

(32)

ATSRAC – HWG10

Lessons Learned

• HWG-10 determined areas of need:

– Awareness and Training

– Installation Guidance (FAA driven – Standardization Issues)

– Inspection Criteria

– Maintenance Procedures

(33)

HWG-10 Recommended

FAA and industry implement an “EWIS

Awareness” program to effect cultural

change

Rationale

– The aircraft evaluations support the need for TC and STC holders, approvers, designers,

installers, and technicians to become more aware of the concepts of EWIS during design,

certification, installation and maintenance.

HWG-10 feels that the current regulations with slight modifications are adequate if properly communicated and enforced.

(34)

HWG-10 Recommendations

FAA

• FAR Part 147 Appendix E is revised to

include the concepts of AC 120-YY

(EWIS, Detailed Inspection (DET),

General Visual Inspection (GVI), and

Special Detailed Inspection (SDI)).

Rationale

X To fully effect a culture change, in the aviation industry, this should include a

“ground up” approach (e.g. future technicians are trained from day one on EWIS concepts)

(35)

HWG-10 Recommendations

FAA

• The following Advisory Circulars be revised

to include EWIS concepts:

– 43.13 – 43.204 – 65-9A – 65-11B – 65-12A – 65-15A

* concepts and language with standardized criteria for EWIS

(36)

HWG-10 Recommendations

Rationale

– These Advisory Circulars are the basis for

certification, maintenance, and training of industry personnel.

– “EWIS” concepts revision would generate

awareness to a large group of existing and future approvers, designers, installers, and technicians.

(37)

Installation Guidelines/Criteria

Standardization - Installation Guidelines must

be FAA/Industry driven

– Currently, Installation Guidance is based off of:

• AC43.13 – Outdated Needs to Be Revised to Latest Technologies

– Current Non-Turbine Powered Aircraft have more technology than AC can support

• ATA Spec 117

• ANM-104 – Created Confusion throughout ACOs and subsequently industry

(38)

Inspection Criteria

Rationale

• There is a lack of Inspection Criteria for

wiring and its subcomponents.

• Development of this Criteria will ensure

that inspectors know what is to be

(39)

Maintenance Procedures

Recommendations

• Review existing manufacturer

inspection/maintenance programs and

enhance for EWIS considerations

• Manufacturer standards - wiring

practices

– pass fail criteria

(40)

Maintenance Procedures

OEMs and STC Holders to enhance the

current Maintenance Procedures

– Enhancement doesn’t necessarily drive to

EZAP.

• Maintenance Program Development

Philosophies of the Various STA OEMs should be capable of enhancing current programs

incorporating concepts of EWIS

• Future Small Transport Aircraft Designs will

most likely follow the version of MSG-3 of that time period or applicable analytical logic process of that time period.