Browse Topic: Airline fleets

Items (61)

eVTOL Modeling Frameworks: A Comparative Study

F-0080-2024-1230

5/7/2024

For the last few decades, Canada's National Research Council (NRC) has been at the forefront in analyzing dynamic systems and developing tools to construct aircraft models based on flight test data. With a fixed and rotary-wing aircraft fleet available, NRC has the capability to perform leading edge R&D System Identification (SI); this worldleading SI technology has been developed and has assisted industry partners, Department of National Defense (DND), and various universities in aircraft simulation and development. As a result, NRC has gained extensive experience in modeling aircraft using SI techniques. In collaboration with CAE, this paper demonstrates the acceleration of the NRC's current flight modeling techniques, highlighting recent advances in Artificial Intelligence (AI) and Machine Learning (ML). A new Bayesian ML software is being developed to identify a 6 degrees of freedom (6-DoF) quasisteady model using simulated flight test data. To achieve this, data from the CAE Sample electric Vertical Take-Off and Landing (eVTOL) simulation platform vehicle during hover maneuvers is utilized. Additionally, this paper presents results on extending the model to include rotor dynamics using the classical SI approach for comparison purposes. In summary, all methods provide a high-fidelity model; with the higher model structure, the vertical acceleration match was noticeably better.

Hui, Kenneth, Hodonou, Claudia, Myrand-Lapierre, Vincent

U.S. Army Rotary-wing Airframe Defect Trending, Modeling, and Analysis

F-0076-2020-16313

10/5/2020

The U.S. Army monitors the structural integrity of its rotary-wing aircraft fleet through annual evaluations and reporting via the Airframe Condition Evaluation (ACE) program. ACE evaluations capture the location and character of structural defects for each aircraft, which are then available for trending and detailed analysis by engineers with the U.S. Army Combat Capabilities Development Command Aviation & Missile Center (CCDC AvMC). As analytic methods are increasingly advanced through the digital thread, CCDC AvMC has sought to improve available trending, modeling, and analysis tools beyond status quo to provide higher fidelity visuals to both aid communication with decision makers, and also to reveal structural defect trends which may not otherwise be evident. This paper will detail the development and utility of the ACE Color Mapping Application within the ACE Mapping Module and its impact on product support of U.S. Army aircraft with regard to airframe structural integrity.

Peltier, Jared, Chhotu, Prasant

A Twenty-five-year Retrospective Analysis of Australia's Previous Defence Aviation Safety Framework

F-0076-2020-16348

10/5/2020

Australia has embarked on an extraordinary reform to design, develop and implement a new and contemporary Defence Aviation Safety Framework. The program seeks to establish a single Defence Aviation Safety Authority (DASA) and issue a comprehensive and integrated suite of Defence Aviation Safety Regulation (DASR) for initial and continuing airworthiness, flight operations, air navigation, aerodromes (inclusive of ship-borne heliports) and safety management systems. While reforms of this scale can often be triggered by reviews into major aircraft accidents, such as The Nimrod Review by Charles Haddon-Cave QC in October 2009, Australia initiated the reform when new aircraft fleets were being introduced and at a time of arguably high-levels of aviation safety. The purpose of this paper is therefore to explain the compelling reason for change; providing a twenty-five-year retrospective analysis of Australia’s previous Defence aviation safety framework to give a rich picture of the difficulties faced by increased commercialization from the late 1990s, globalization in the 2000s, and the recent emergence of strict work, health and safety legislation in Australia.

Hood, James, Marzocca, Pier, Sinha, Arvind

Method to Calculate Behind Start of Takeoff Roll Noise Level Adjustments

AIR6297 (Current)7/6/2017

This document describes a method to calculate noise level adjustments at locations behind an airplane (described by an angular offset or directivity) at the start of takeoff roll (SOTR). This method is derived from empirical data from jet aircraft (circa 2004), most of which are configured with wing-mounted engines with high by-pass ratios (Lau, et al., 2012). Methods are also described which apply to modern turboprop aricraft. Calculations of other propagation-related adjustments required for aircraft noise prediction models are described in AIR1845A, ARP5534, ARP866A, and AIR5662.

A-21 Aircraft Noise Measurement Aviation Emission Modeling

Equivalent Level of Safety Methodology for Structural Usage Credit

F-0073-2017-12172

5/9/2017

ABSTRACT Usage credits may be used to extend retirement lives for structural components. However, any credit substantiation must account for the contribution of conservative usage assumptions to the current level of safety. Structural reliability methods have been proposed as a means to achieve this end. Herein a new, relative method to determine a practically equivalent reliability (and safety) for aircraft fleets is developed using system reliability theory. Simple mathematical examples are used to illustrate the basic principles. A more realistic example based on the AHS Fatigue and Damage Tolerance subcommittee Round Robin problem is presented. These examples show that, even if only a few aircraft in a fleet operate in a severe manner, these aircraft drive the overall fleet reliability. This means that many aircraft may be able to receive credit without having any appreciable change on fleet reliability. A generalized procedure to apply the method to real world problems is developed. Use of the method as part of a certification methodology is presented along with a justification of what change in reliability would be practically equivalent. Application of this method may allow for safe extension of component lives based on usage.

Tucker, Brian, Muniz, Rick, Neus, Michael, Green, Paul, Altman, Leigh, Barbarin, Alejandro

Flight Testing of Health Management Technologies

F-0073-2017-12080

5/9/2017

ABSTRACT The U.S. Army traditionally has used a time-based, on-condition maintenance paradigm that relies on at-aircraft inspections and periodic in-depth phased inspections to determine condition and ensure airworthiness. The result is a significant maintenance burden, both scheduled and unscheduled, and excessive aircraft downtime. The objective of the Aviation Development Directorate (ADD) and Sikorsky Aircraft Corporation (SAC) Capability-Based Operations and Sustainment Technology-Aviation (COST-A) program was to develop and demonstrate an integrated set of high value diagnostics, prognostics, and system health management technologies that reduce scheduled inspections and preventive maintenance while enhancing safety. More than two dozen Prognostics and Health Management (PHM) technologies across six primary rotorcraft systems (propulsion, drive train, airframe/structural, rotor, electrical, and vehicle management) were matured to technology readiness level (TRL) 6. These technologies were integrated into a prototype laboratory on-board system built around the Integrated Vehicle Health Management Unit (IVHMU) currently installed in all UH-60 Black Hawk aircraft and successfully demonstrated to perform concurrently in representative simulated flight scenarios, using playback data from healthy and faulty components. A subset of these technologies, jointly selected by ADD and SAC, was flight tested on an HH-60M aircraft to further reduce the risk of transitioning these technologies. This paper summarizes the flight-test efforts, with a focus on results obtained for the technologies under test. Upon deployment to the UH-60 aircraft fleet, these PHM technologies can enable the Army to transition to a more effective automated condition-based maintenance (CBM) paradigm.

Brookhart, Andrew, Lyman, Chris, Davis, Mark, Bates, Preston, Cycon, Jim, Pantelis, Paul, Baker, Treven, Bordick, Nathaniel

Flight Test Preparation of Health Management Technologies

F-0072-2016-11474

5/17/2016

The U.S. Army traditionally has used a time-based, on-condition maintenance paradigm that relies on at-aircraft inspections and periodic in-depth phase inspections to determine condition and ensure airworthiness. The result is a significant maintenance burden, both scheduled and unscheduled, and excessive aircraft downtime. The objective of the Aviation Development Directorate (ADD) and Sikorsky Aircraft Corporation (SAC) Capability-Based Operations and Sustainment Technology-Aviation (COST-A) program was to develop and demonstrate an integrated set of high value diagnostics, prognostics, and system health management technologies that reduce scheduled inspections and preventive maintenance while enhancing safety. More than two dozen Prognostics and Health Management (PHM) technologies across six primary rotorcraft systems (propulsion, drive train, airframe/structural, rotor, electrical, and vehicle management) were matured to technology readiness level (TRL) 6. These technologies were integrated into a prototype laboratory on-board system built around the Integrated Vehicle Health Management Unit (IVHMU) currently installed in all UH-60 Black Hawk aircraft and successfully demonstrated to perform concurrently in representative simulated flight scenarios, using playback data from healthy and faulty components. A subset of these technologies, jointly selected by ADD and SAC, has been prepared for an upcoming flight test on a UH-60M aircraft to further reduce the risk of transitioning these technologies. This paper summarizes the flight-test preparation efforts, including the implementation of associated algorithms within a representative integrated on-aircraft and ground-based system software environment. Upon deployment to the UH-60 aircraft fleet, these PHM technologies can enable the Army to transition to a condition-based maintenance (CBM) paradigm.

Brookhart, Andrew, Lyman, Chris, Davis, Mark, Bates, Preston, Cycon, Jim, Baker, Treven, Bordick, Nathaniel, Pantelis, Paul, Thompson, Bruce

Touch and Go

15AERP12_0112/1/2015

Avionics developments are changing life in the cockpit and at airborne work stations. Since the digital revolution changed forever the pilot's working environment, innovators and suppliers of cockpit systems have strived to provide a continuous stream of new developments and products that offer increasingly automated solutions to what has to be done to fly and land an airplane safely. As the first “glass” cockpits with CRT-type displays were introduced in the 1980s, there was understandably much opposition from many within the active flying community as these revolutionary devices removed at a stroke all those scores of instruments that were so familiar and which all seemed absolutely essential at the time.

How Tools and Process Improved Diagnostic and Prognostic Reaction Time

2015-01-25899/15/2015

Modern aircraft, such as A380 or A350 for Airbus, are very well connected in flight to ground stations through wireless communications. For maintenance and operations purpose, the aircraft is programmed to send regularly information such as flight reports based on the BITE messages (Built-In Test Equipment) or standard reports based on the value of physical parameters. Moreover, Airbus is capable of sending requests (called uplinks) to the aircraft to retrieve the value of different parameters in almost real-time. This ability, associated with adequate process, improves significantly the reaction time of the diagnostic and prognostic solutions that Airbus can provide to its customers. Traditionally Health Monitoring is considered useful when the Potential to Functional failure (P-F) interval is greater than one flight cycle. This is due to the fact that it usually takes at least a flight cycle to collect and analyze data, and because on-board systems are responsible for managing failures that have an effect on current flight. But, in some circumstances, operational interruptions cannot be avoided by on-board systems and health monitoring solutions can be a useful mitigation mean as long as their reaction time is quick enough. In this paper is presented a case where an environmental corruption of sensors during aircraft Turn-Around Time (TAT) on ground can lead to an operational interruption before take-off. The consequences of this case are averted by the implementation of tools and process that allow a very quick reaction time. By collecting data just after engine start, analyzing them and informing the operator within 10 minutes, Airbus was able to avoid an operational interruption to occur during take-off rolling phase, reducing significantly its severity. This paper describes the study, the process setup and the performance of the solution implemented.

Feau, Julien, Chantal, Philippe, Sen Gupta, Jayant

Time-Domain Terahertz Computed Axial Tomography NDE System

TBMG-1506011/1/2012

NASA has identified the need for advanced non-destructive evaluation (NDE) methods to characterize aging and durability in aircraft materials to improve the safety of the nation’s airline fleet. 3D THz tomography can play a major role in detection and characterization of flaws and degradation in aircraft materials, including Kevlar-based composites and Kevlar and Zylon fabric covers for soft-shell fan containment where aging and durability issues are critical.

Going modular with airborne radar

12AERD0215_042/15/2012

Innovative approaches to solving the affordability challenge posed by too many specialist airborne surveillance systems. Air forces, armies, and navies around the world are only too aware that airborne surveillance is perhaps the most essential element in today's military inventory. The problem for armed forces that are seeking to invest in new airborne surveillance platforms is a big one: there are plenty of different aircraft and systems available that cover specific mission capabilities, but few of them offer adaptability and mission flexibility. And that means priorities have to be carefully considered when it comes to procurement, with difficult choices having to be made against a backdrop of decreasing affordability.

Gardner, Richard

Co-Operation in Calculations and Monitoring the Aircraft Noise in Airports with Dominant Contribution of FSU Aircraft

2010-36-055010/17/2010

For assessment of the aircrafts noise impact on the community near to airports the acoustic calculations and measurements may be used. Obtained measurements results show ~1 dBA for LAeq coincidence with calculations results and allow to prepare correct database for practical use under ECAC method. While results of LAmax estimation still remain under investigation. These requirements are important first of all for aircraft, which are designed in FSU, Russian Federation and Ukraine. Their contribution to the aircraft noise impact in airports of FSU countries is still dominant, so their correct input data is still necessary.

Jagniatinskas, Aleksandras, Zaporozhets, Oleksandr, Kartyshev, Oleg, Fiks, Boris

Aircraft Movement Indicator

2008-36-05703/30/2008

Aircraft noise is considered to be one of the most difficult environmental problems to be mitigated from the airport operations. The ICAO study group has presented an approach with four proposals to manage this problem at each site – the “Guidance on the Balanced Approach to Aircraft Noise Management” –, but even with this document, the airport managers still have to do their plan of action to address the most problematic ones (cases where there is more than one airport under the same administration). In this way, this paper attempts to propose a methodology to help to identify what would be the equivalent aircraft movement in a month for each site. The hypothesis is that this indicator number will express how close the airport operation is to the Balanced Approach proposals. And to calculate it, this methodology uses the number of movements identified by Chapter 2 or Chapter 3 and by day or night for a given period. To show the application, this paper presents a rank of the biggest Brazilian airports by an Aircraft Movement Indicator.

Valim, Fernanda, Slama, Jules

The Propulsion - Safety, Affordability, and Readiness Program

TBMG-467710/1/2006

Propulsion - Safety, Affordability, and Readiness (P-SAR) is a new and unique program effort intended to achieve common engine sustainment goals across the Army, Navy, and Air Force aircraft fleets (see figure). Originally conceived as a follow-on to the highly successful High-Cycle Fatigue (HCF) program, P-SAR is evolving into a benchmark collaboration initiative that includes all Department of Defense (DoD) propulsion organizations, as well as National Aeronautics and Space Administration representatives and turbine engine original equipment manufacturers.

Autonomous Formation Flight

TBMG-292462/1/2004

NASA's Strategic Plan for the Aerospace Technology Enterprise includes ambitious objectives focused on affordable air travel, reduced emissions, and expanded aviation-system capacity. NASA Dryden Flight Research Center, in cooperation with NASA Ames Research Center, the Boeing Company, and the University of California, Los Angeles, has embarked on an autonomous-formation-flight project that promises to make significant strides towards these goals.

Airline Pilots' Perceptions of and Experiences in Crew Resource Management (CRM) Training

2002-01-296311/5/2002

We surveyed over 30,000 airline pilots to assess their perceptions of and experiences in their professional training. In this paper, we describe their responses to a series of questions that focus on Crew Resource Management (CRM) training. The results suggest that most pilots are satisfied with their CRM training and find it useful. However, the respondents indicated that training programs which integrate CRM principles throughout the entire curriculum are substantially more useful than stand-alone CRM training courses.

Beaubien, J. Matthew, Baker, David P.

The Benefits of a Wire Integrity Program

2002-01-293911/5/2002

Aircraft are aging. Wiring on aircraft is mostly inspected visually with little emphasis on non-destructive testing. Current “on-condition” practices are time consuming, costly and subject to human factors. Wiring should to be considered as a system on the aircraft and analyzed on a proactive basis, similar to the engines and the structure. New technologies are available to enable a wire integrity program.

Gau, Francois

Specification Reform of Avionics Thermal Design Criteria – An F-15 Case Study

2001-01-21567/9/2001

Traditional thermal design criteria for avionics equipment are reviewed. Several studies have recently been conducted on the F-15 to assess accuracy of these design criteria. An overview of the study approach and results are presented. Specific topics investigated include: emergency cooling air provisions, cold start-up, hot start-up, normal and transient bay temperatures, and altitude design. The results indicate that many existing design criteria are overly conservative. The study findings suggest that reform of the existing thermal specification process is needed. Many of these reforms are applicable to the general aerospace industry and may result in significant acquisition cost savings as a result of the trend toward usage of commercial electronic parts. The reforms suggested include a new performance based thermal specification approach that increases emphasis on aircraft usage and frequency of occurrence. New transient design criteria are also recommended. Questions are raised regarding adequacy of the current equipment qualification process when using the reforms presented. Additional work in this area is suggested.

Eason, Myron, Lutter, Robert N., Smith, Thomas C.

Regional Aircraft Family Design

2000-01-554710/10/2000

A design concept of an aircraft family (55 -, 70-, 100-seater) is presented. Started with the reference model of 70-seater, a stretch to 100-seater and shrink to 55-seater is considered ab intio. Impact of commonality in a fleet of different size aircraft is investigated. Passenger comfort, operating aspects and cost are main design drivers. Fly-by-wire flight controls, all-glass cockpit with utility management are applied technologies to end up with an attractive product.

Birrenbach, Reinhold

Intelligent Damage Adaptive Control for Commercial Air Transports

1999-01-14364/13/1999

In situations of unanticipated maneuvers of an aircraft, information must be immediately received by the aircrew for correcting the aircraft flight path to a safe trajectory for continued flight and landing. These maneuvers may be due to failures in the control system, wind gust upsets, or other off-nominal conditions. Also critical are situations of control maneuvers that exceed the normal flight envelope of the aircraft, and providing information to the pilot and control system that will result in safe return to controllable flight. The Intelligent Damage Adaptive Control System (IDACS) operates during flight to detect dangerous conditions of the aircraft and to provide the crew with assistance to restore and to maintain safe control. This system is being developed by Boeing for NASA.

Urnes, James M.

Safety Enhancements Available by Converting MSG-2 Aircraft Maintenance Programs to MSG-3

1999-01-14404/13/1999

Safety is central to the maintenance program philosophy of today’s Air Carriers. Both MSG-2 and MSG-3 analysis procedures/logic have been used to develop a majority of the routine scheduled maintenance and inspection programs of Transport Category Air Carriers (those that operate under 14 CFR 121 [Title 14, Code of Federal Regulations, Part 121]; a.k.a., FAR 121). MSG-3 is a significant procedural shift from MSG-2; providing a more comprehensive decision logic flow, a “top down” consequence of failure approach, separating evident and hidden functional failures, clearly distinguishing safety related consequences from economic/operational consequences, and resulting in a more easily understood task-oriented program. This paper does not replace formal MSG-3 training, nor fully detail transitioning maintenance programs, but simply focuses on the safety benefits derived from the effort required to convert an existing MSG-2 derived program to MSG-3.

Anderson, Richard W.

Using Emerging Computer Database, Software, and Communications Technologies in Fleet Management

9812104/6/1998

The goal of any aircraft fleet manager is to field, fully utilize, and retire a fleet without a single catastrophic structural failure and accomplish this at minimum cost. That goal is modified depending on the point of view of the specific manager. The Aircraft Structural Integrity Program (ASIP) manager emphasizes “without a single catastrophic structural failure”. The fleet and operations managers emphasize “minimum cost”. Managing the fleet from a structural integrity stand point often on the surface appears to be a costly program. Other fleet managers may not see the immediate benefits of effective structural integrity programs. In today=s environment of austere budgets we, as structural integrity engineers, must search for methods of protecting the structure of the fleet at minimum cost. This means making pinpoint decisions timely and effectively. These decisions involve repairs, modifications, maintenance actions, and inspections. Effective structural management can only take place from an “informed position”. Decisions must be made on the basis of complete and sound fleet information. These fleet data must be centrally located, secure, easily accessed, and complete. This paper focuses on using modern emerging computer, database, and communication technologies to enhance fleet data collection and efficient use of the data collected.

Giese, Robert D., Herring, Grant

Defining the Operational Structural Loading of Commercial Transport Systems by Airborne Data Monitoring

9812004/6/1998

The application of individual airplane structures and systems tracking to commercial transports has been slow. This paper discusses a procedure by which data collected on a representative sample of a commercial transport fleet can be used to understand aircraft loading cycles on systems and structures.

Barnes, Terence J., Hempe, David W.

Using Information Technology and Simulation to Reduce the Commercial Aircraft Accident Rate

97552910/1/1997

A collaborative government/industry effort to reduce the commercial aircraft accident rate is described. The proposed program is based on established military technology and will incorporate the routine application of advanced nondestructive inspection techniques. An aircraft Information Management System (AIMS) is suggested as the program's data archive and central information and tracking network. The program will provide continual monitoring of the condition of individual aircraft by the owners and operators, and, through trend analysis, by the manufacturers and cognizant transportation authorities.

Larsen, Willam E., Cooksy, Kevin D.

Benefits Derived from Tracking Engine Performance of Flight Inspection Aircraft

9714855/1/1997

This paper provides an overview of the approach taken by the Federal Aviation Administration for tracking and evaluating the performance of the engines installed on Flight Inspection Aircraft. The Flight Insepction Aircraft are used to verify the accuracy of domestic and international navigational equipment. The engine recorded data enables maintaining operational efficiency and permits timely maintenance actions.

O'Neal, Gary E.

Aerospace Maintenance Skills - Today and Tomorrow

94213110/1/1994

The maintenance of aerospace products, in the commercial, military, and the space environments requires specific human skills. This paper examines the basic philosophy of maintenance in each area and describes the skills required to support the philosophy. There are both common and unique elements between the philosophies, and the required skills. These are illustrated in a chart format, and the effects of a downsizing aerospace industry are examined for each area.

Matson, Robert

The FAA Regional/Commuter Aircraft Flight Loads Data Collection Program

9312585/1/1993

As a part of its International Aging Aircraft Research Program, the Federal Aviation Administration is establishing a state-of-the-art Flight Loads Data Collection Program. Data collected in this program will provide the necessary mission profiles and load spectra information to characterize typical fleet service usage for the regional/commuter service life extension program. In addition, these data are applicable for both a safe life fatigue analysis and a damage tolerance fracture mechanics analysis. This paper describes the FAA approach and schedule for instrumenting fleet service aircraft, and the data reduction process.

DeFiore, Tom, Barnes, Terence

Improved Optical Interlayer Systems Show Bond Stability at High Temperatures, High Humidity

9111364/1/1991

Tempered glass, once the optimum material for aircraft vision systems, is now being replaced by high-strength, lightweight plastics. Specially designed acrylic, glass, and polycarbonate laminates offer weight savings that give them a distinct advantage in weight-critical aerospace applications. Like tempered glass, laminates must withstand the impact of low-altitude debris and bird-strike as well as the shock of rapid temperature, humidity, and pressure changes. The laminating adhesive must be strong enough to withstand impact and must provide stress relief for the different substrates, which often have very different thermal coefficients of expansion. Liquid and sheet silicone interlayer adhesives have been developed that provide the clarity, adhesion, and performance characteristics required by aircraft windshield and canopy designs. These adhesives have hydrolytic bond stability and high-temperature adhesion that are substantially greater than those of nonsilicone adhesives. This means that windshield replacement due to delamination is less frequent, significantly decreasing the costs of grounded craft and the maintenance required. This paper gives new data on the high-temperature adhesion and hydrolytic bond stability of sheet silicone interlayer adhesives. Adhesion to acrylic was tested from -50°C to 125°C; adhesion to polycarbonate was tested from -50°C to 150°C; adhesion to glass was tested from -50°C to 250°C. Hydrolytic bond stability was tested at 100% relative humidity at various temperatures and compared to results with polyvinylbutyral and polyurethane adhesives.

Larson, Kent

AIRBORNE GLOBAL POSITIONING SYSTEM RECEIVER

ARINC743 (Current)3/1/1990

This standard provides design guidance for the development of GPS sensors for airline use. It describes the operational capability of the GPS receiver and the standards necessary to ensure interchangeability. GPS provides navigation data to pilots and provides data for use by other aircraft systems.

Airlines Electronic Engineering Committee

Evaluating the Effectiveness of Cockpit Resource Management Training

89260112/1/1989

The impact of Cockpit Resource Management (CRM) training can be evaluated using as criteria the behavior of crews in simulator and line flights, changes in attitudes regarding crew coordination and flightdeck management, and self-reports of participants regarding the utility of the training. Preliminary findings from a NASA-sponsored study of CRM effectiveness indicate significant effects on all three types of measures. However, the data also show that not all participants benefit from the training and some show a “boomerang effect” - showing less favorable attitudes regarding crew coordination following the initial CRM course. Issues that may enhance or diminish the effectiveness of CRM training and Line Oriented Flight Training (LOFT) are discussed.

Helmreich, Robert L.

Maintenance and Economic Benefits of Non-Painted Aircraft Operations

8922089/1/1989

Alclad aluminum sheet has been used for decades as the material of choice for aircraft fuselage sheet. Producers have developed and improved aluminum alloys that today allow airline companies to fly polished unpainted aircraft that are attractive, unique and instantly identifiable to the traveling public. The use of polished fuselages not only provides an attractive exterior but also offers functional benefits. These include fuel savings by flying with less paint, maintenance savings from reduced down time during C and D checks, reduction in hazardous waste disposal, and improved inspection capabilities. Arguments for both sides of this issue are sound. However the proven advantages of flying non-painted polished aircraft necessitate consideration of the concept of flying non-painted polished fleets for improved economic performance.

Skluzak, Dell F.

Manufacturing and Handling Techniques Used in the Assembly of Polished Commercial Aircraft

8909254/1/1989

The use of polished aluminum fuselage skins has been a standard on U.S. commercial jet transport aircraft for decades. Increasingly stringent environmental regulations for paint stripping combined with fuel and maintenance savings allows consideration of flying polished non-painted aircraft. Boeing, McDonnell Douglas and Embraer currently manufacture commercial aircraft with polished alclad aluminum fuselages. Commercial airlines such as American Airlines, USAir, Eastern, Northwest and ASA fly non-painted fleets. These customers require the aircraft to be delivered with a polished appearance incorporating minimum fleet graphics. The manufacturing of polished aircraft requires unique production and handling procedures to fabricate all exterior panels with identical color match and reflectivity. This paper compliments previous papers on the economic advantages of non-painted planes and transition procedures from painted to non-painted aircraft. (1)* The various procedures used to produce and protect the valuable skin material from the plant to delivery of the fully assembled aircraft will be fully explored. THE COMPLEXITY OF PRODUCING an entire fuselage with aesthetically pleasing and uniform appearance is enormous. Airframe fabrication ranges from severly stretch-formed to substantially chem-milled parts, requiring special mill fabrication. Tailor made practices for the exterior aluminum skins allow for consistent manufacturing results while maintaining an extremely constant finish for the fuselage. As an example, Northrop Corporation has produced the fuselage of the 747 since inception of the program. The improvements in handling and manufacturing of the aluminum skins have advanced through the years. Even the 747, with its massive fuselage resembles a mirror-like surface with color-matched and defect-free panels. The integrity of the aluminum can only be sustained by careful manufacturing techniques. Implementation of these standards often raise the entire consciousness of quality needs for other components of the aircraft. The attention given to equipment, parts handling, techniques and awareness has helped reduce reject and rework levels while raising the quality of all parts produced. The result to the fleet purchaser is an aircraft with unmatched quality. The overall economic savings by flying unpainted aircraft are ever increasing. The cost of jet fuel savings alone for a 747 is nearly $200,000/year with fuel at $.50/gallon (see Figure 1). Additional savings of faster maintenance schedules, elimination of strip/repaint cycles and ease of inspection also support the operation of a polished non-painted fleet. Specifically, painted surfaces tend to develop filiform corrosion. During Eastern Airlines conversion to unpainted aircraft, filiform corrosion was noticed on aircraft as new as three years old. Since conversion to unpainted aircraft, Eastern's rate of filiform corrosion has been reduced to near zero. (2) The recent air worthiness directive's (AD) by the FAA, requiring stripping and eddy current testing of rivets for early model 737's, points out clearly the potential for increased inspection of the world's rapidly aging fleet. The cost to strip the 100 737's involved in the inspection is nearly 60 million dollars. (3) The ability to eddy current test and inspect the affected areas is greatly facilatized by starting with a surface that does not require the initial stripping.

Skluzak, Dell F., Whicker, Jerry T.

How to Make the Successful Transition from a Painted to a Polished Aluminum Aircraft Fleet

880874

4/1/1988

Environmental regulations are tightening worker exposure limits and disposal options for airlines who chemically strip and repaint their fleets. An alternative is to operate a polished aluminum aircraft fleet. The authors present an explanation of the grades of alclad aluminum fuselage skins used by commercial aircraft manufacturers and offer instructions on how to polish the unpainted alclad aluminum in order to operate the aircraft in the polished look. All fuselages on aircraft built by Boeing, Douglas, Lockheed, and the new EMBRAER Brasilia, were assembled using premium grade polished alclad aluminum. As a result, painted versions of aircraft built by the airframers have the capability to be stripped, polished and put in service as a polished aluminum aircraft.

Cieslak, Stanley J., Whicker, Jerry T.