Browse Topic: Airline fleets

Items (65)

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

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

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

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

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

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

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

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

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

Touch and Go

16MEIP03_043/1/2016

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

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

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

Mechanical and Structural Aspects of the C-17 Cargo Ramp and Cargo Door ADFS

2002-01-26289/30/2002

The cargo ramp and cargo door are two major C-17 components that are built in St. Louis, MO and shipped by rail for final assembly in Long Beach, CA. A major portion of the total build time for the ramp and door assemblies consisted of the hand installation of approximately 16,000 moldline fasteners and 19,400 moldline fasteners, respectively, attaching the skin to the substructure. In addition, several thousand fasteners are also installed in the floor sections of the ramp and door. A major cost savings opportunity existed to reduce the cost of the ramp and door assemblies by automating the installation of these fasteners. Boeing-St. Louis contracted Brotje Automation of Wiefelstede, Germany to design and build an automated drilling and fastening system (ADFS). Automation is expected to reduce cost by reducing the time required to build the ramp and door assemblies. In addition, automation is expected to improve fastener hole quality and fastener installation quality. Another

Muñoz, Philip R.

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

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

Building a family

AEROAPR01_041/1/2001

Fairchild Dornier takes the family approach to developing its various regional jet aircraft. To remain competitive as well as meet the market demands of regional airlines, Fairchild Dornier has adopted the strategy of developing a family of aircraft. The latest series of aircraft under development by the company begins with the 70-passenger 728JET, which is scheduled to enter service in 2003. This aircraft will be followed by the 50-passenger 528JET in 2004 and the 100-passenger 928JET in 2005. Strong cost competition has forced major airlines to form global alliances so they could achieve control of the regional air transport systems. Airlines now also play an important role in the decision-making processes of regional aircraft manufacturers. They require comfort equivalent to large aircraft standard, the same level of reliability, all-weather capability, and a turn-around time less than 20 min-but at a lower cost than today's turboprops.

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

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.

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.

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 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

Giese, Robert D., Herring, Grant

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

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

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.