Flight Certification Research Articles

Maintenance management system for a defence aircraft development programme

Design and development of a defence aircraft involves solving of multi disciplinary problems over the development lifecycle. The ground and flight tests evaluation play a crucial role during the certification of the aircraft. The observations from the field trials viz. reported failures and corrective actions taken are of immense value for the performance assessment of aircraft. In addition to the aircraft performance assessment and root cause analysis of the failures, the data from the field also facilitates to assess and refine the maintenance procedures. This paper brings out a conceptual model of computerised aircraft maintenance management system (CAMMS), which is a product lifecycle management (PLM) enabled enterprise–wide solution involving designers, maintenance planners, test pilots, flight test engineers, inspectors and certification agency. This supposed system will encapsulate a framework for failure reporting analysis and corrective action that shall assist in failure, reliability and maintainability analysis, aiding a tighter control on the schedule and budgetary escalation.

Practical PHM for Medium to Large Aerospace Grade Li-Ion Battery Systems

In this paper we will discuss some practical aspects of health management for a rechargeable Li-ion battery system for aerospace applications. Industry working groups have developed guidance for the flight certification of this type of battery system, and we will show how this guidance is used in the design. We will also discuss safety features embedded in the battery system related to industry guidance; including cell energy balancing, internal temperature monitoring and emergency fuses. The keys to battery prognostics and health management (PHM) are analytic State of Charge (SoC) and State of Health (SoH) algorithms implemented in these battery systems. We show how these are developed and how we have tested them before deployment. These battery systems also collect data that is made available to the aircraft processing systems, e.g., Aircraft Health Management System, On-board Maintenance System, etc.. This allows for near real-time confirmation of proper operation of these battery systems as well as adherence to MSG-3 maintenance standards. We close with a brief discussion of the practical limitations in our implementation and a discussion of our ongoing and future development in this area.

한국형 기동헬기 계기비행 인증절차 및 비행시험 결과

본 논문에서는 한국형 기동헬기의 계기비행 인증절차 및 주요 비행시험 결과를 제시하였다. 한국형 기동헬기의 계기비행 인증을 위해 장착된 계기 및 장비의 적합성을 검토하였으며, 지상 및 비행시험을 통해 검증하였다. 아울러 항공기가 충분한 종축, 횡축 및 방향축에 대한 정안정성 및 동안정성을 보유하고 있는지를 확인하기 위해 FAR-29 Appendix B에 따라 시험을 실시하였다. 정안정성은 주로 조종입력에 대한 항공기의 속도 및 자세 변화를 통해 판단하였으며, 동안정성은 장주기 및 단주기 입력 후 항공기 거동이 얼마나 빨리 수렴하는지를 통해 평가하였다. 조종사의 임무부하 평가는 IMC 모사 비행시험을 통해 이뤄졌다. 본 논문에서는 항공기가 정상적인 상황뿐만 아니라 비행조종, 엔진 및 계기 등에 고장이 발생한 상황에 대한 임무부하 평가결과도 함께 제시하였다. IMC 모사 비행시험이 완료된 이후에는 실제 IMC 환경에서 항공관제에 맞춰 실제 계기비행시험을 실시하였다. In this paper, the instrument flight certification process and flight test results of Korean Utility Helicopter (KUH) are presented. For the instrument flight certification, the suitability of installed equipments and instruments have been reviewed and verified by ground and flight tests. Next, static and dynamic stability test are conducted in accordance with FAR-29 Appendix B. The static stability is determined by the change of speed and attitude according to control inputs. The dynamic stability is evaluated by how quickly the response of the helicopter due to long and short period control inputs are decreased. The pilot workload evaluation are also carried out by simulated IMC flight tests. This paper presents the workload assessment results when some failures are occurred at cockpit instruments, engine or flight control systems as well as the normal situation. After the simulated IMC flight test is completed, actual instrument flight test are conducted in a real IMC environment according to the air traffic controls.

Method for Evaluating Data Communication Messages in NextGen Flight Deck Scenarios

Data communications (DataComm) is one of the Federal Aviation Administration’s (FAA) key technologies supporting the transition to the Next Generation Air Transportation System (NextGen). As communication on the flight deck changes from voice clearances to clearances sent via datalink, human factors experts have anticipated potential implementation challenges, particularly for the data communications that may not be integrated with the flight management system (FMS) and which requires the flight crew to read the DataComm message, interpret it, and then make the appropriate FMS input. Even fully integrated DataComm and FMS flight deck systems could prove challenging for flight crew use in the Trajectory Based Operations context. For example, textual clearances that provide complex 4D trajectory information may be difficult for pilots to interpret in a timely and efficient manner without error. To address this challenge, flight deck displays with graphics, hybrid text and graphics, and other formats integrated with existing navigation displays may enable pilots to more easily identify, understand, and quickly respond to air traffic clearances and instructions. To support FAA Aircraft Certification Service and Flight Standards Service evaluation of new DataComm flight deck technologies and associated procedures for Trajectory Based Operations and other key NextGen applications, this paper describes a method that allows rapid evaluation of new and modified DataComm displays in the cockpit. Our method uses a variety of complex data communications, including the use of concatenated messages to obtain rapid pilot feedback and performance in a part-task, scenario-based simulation. Average data values from an initial study evaluating pilot interpretability measured as percent errors and response time to text-based clearances are presented.

Flight Tests, Performances, and Flight Certification of a Twin-Engine Light Aircraft

This paper deals with flight test activities performed on P2006T, a twin-engine light aircraft recently designed and produced by Tecnam. Research activities and flight tests have been conducted during the flight certification of P2006T for the normal category under CS23. All the acquired data and flight results presented have been focused on both aircraft certification and on aircraft performances, stability and flight qualities measurement. The data have been acquired through a light, accurate and reliable flight instrumentation available at DIAS (Department of Aerospace Engineering). Some flight data about aircraft leveled speed, stall speed, climb characteristics and ground performances (take-off and landing) will be presented. After preliminary flight tests, winglets have been designed and added to the final configuration in order to obtain good climb performances also in OEI (One Engine Inoperative) conditions. Accurate stall tests have been performed in all configurations and influence of both entry-rate and load factor on stall speed have been highlighted. Excellent ground performances have been measured with short take-off and landing distances compared with similar airplanes. All measured flight performances can be considered very good for this aircraft category and have been used to demonstrate aircraft safety and to obtain CS23 certification.

Studies on New Air Purification and Air Quality Control System of Airliner Cabin

Airworthiness standards of China and America both give the maximum permissible concentrations of CO, CO2 and O3 in airliner cabin. The general specifications of aircraft engine (GJB241-87, GJB242-87) also have the maximum permissible concentrations of pollutants in the engine bleed air used for the air conditioning system. During airworthiness certification flight tests, the concentrations of these harmful pollutants in cabin are required to be tested and validated. According to these requirements, combined with active and passive control strategies, a new cabin air quality (CAQ) control system was presented based on nano-photocatalytic oxidation (NPCO) purification technique. A CAQ dynamic model was established and used to do simulation analysis of the CAQ control strategies. Results showed that the CAQ control system based on new NPCO device can well handle the CAQ problems in current airliner cabins, and the new CAQ control strategies may help to reduce the CAQ change amplitude, and to improve the CAQ as well.

Medical survey of European astronauts during Mir missions

This paper reviews the medical operations performed on six European astronauts during seven space missions on board the space station Mir. These missions took place between November 1988 and August 1999, and their duration ranged from 14 days to 189 days. Steps of pre-flight medical selection and flight certification are presented. Countermeasures program used during the flight, as well as rehabilitation program following short and long-duration missions are described. Also reviewed are medical problems encountered during the flight, post-flight physiological changes such as orthostatic intolerance, exercise capacity, blood composition, muscle atrophy, bone density, and radiation exposure.

Verification of JEM Structural Compatibility with the Space Shuttle

The JEM elements are delivered to the ISS on three Shuttle flights and are assembled on orbit subsequently. The verification of JEM structural compatibility with the Space Shuttle was performed to certify its flight readiness. Structural compatibilities are required on weight and center of gravity, stiffness and structural damping, strength, and dynamic clearance. Verification results should be reviewed at several assessment stages and needs to be approved by NASA for flight certification. On the other hand, JEM is the Japanese first manned-base facility, and has complicated interface with the Space Shuttle. So several issues were found in the verification phase and have been successfully resolved by technical challenges on Lack of Ascent Performance Margin (APM), Non-linear stiffness of structural latch mechanism, Negative structural margin, and Close clearance / Interference.

Effects of Airsickness in Male and Female Student Pilots: Adaptation Rates and 4-Year Outcomes

Airsickness (AS) often affects aircrew members, especially at the beginning of their flight careers. In this study the AS incidence in 376 Italian Air Force student pilots (336 men and 40 women) was investigated during their initial flight activity. The study was separated into two parts. In part 1, the AS incidence was analyzed in the whole sample to determine the overall characteristics of AS and the hypothetical differences between men and women during the first flight certification (Basic). Part 2 analyzed a subpopulation of 102 individuals (86 men, 16 women) over 4 subsequent years throughout the first 4 flight certifications (for a total of about 60 flight hours). In all cases, AS was evaluated according to the number of flight missions affected by vomiting episodes. The overall AS incidence during Basic was 34.8%, without significant gender differences. However, within AS individuals, a significantly higher percentage of women were slow adaptors (12.5% of the whole female sample vs. 3.3% in men). AS overall affected the likelihood of reaching Basic certification, but this was not significantly related to the number of AS episodes. The 1-yr interval between two subsequent flight certifications caused a loss of adaptation to the flight environment in most cases. The absolute incidence of AS in our study resulted within the expected range, without significant differences between men and women. In a minor number of individuals (11 out of 336 men and 5 out of 40 women) a slow capability of adaptation to AS was observed. Such a finding was statistically more prevalent in women. In contrast to previous literature data, when prolonged interruptions from flight activity are planned, the retention of adaptation in our study did not play a significant role in avoiding future episodes of AS.

Probabilistic Approach to Damage Tolerance Design of Aircraft Composite Structures

*† A probabilistic approach to determine design parameters for damage-tolerant composite aircraft structures has been developed. The main criterion for acceptance of a structure is a specified probability of failure. The development of this approach is motivated by the increasing use of damage-sensitive composite aircraft structures. The resulting probabilistic model takes into account a probabilistic assessment of in-service accumulated damage, the ability of non-destructive inspection methods to detect such damage, the residual strength degradation of damaged structure, quality of repair and loads/temperatures expected between damage initiation and detection/repair. The special attention has been paid to the availability of input probabilistic data and the possibility to obtain such data at reasonable cost. Computing tools and algorithms for the probabilistic analysis have been developed. The validity of the approach has been demonstrated on several existing structural components. The main result of the study is that the reliability of a damage-tolerable composite structure can be assessed on a quantitative basis, allowing aircraft manufacturers, operators and flight certification authorities to establish the maintenance service guidelines and estimate the reasonable inspection intervals. Engineers can use this methodology in the future as a guide to establish design and inspection criteria while considering structural risk and maintenance cost at the same.

NASA crew launch vehicle flight test options

Options for development flight testing (DFT) of the Ares I crew launch vehicle (CLV) are discussed. The Ares I CLV is being developed by the US National Aeronautics and Space Administration (NASA) to launch the crew exploration vehicle (CEV) into low Earth orbit (LEO). The Ares I implements one of the components of the vision for space exploration (VSE), providing crew and cargo access to the International Space Station (ISS) after retirement of the space shuttle and, eventually, forming part of the launch capability needed for lunar exploration. The role of DFT is to demonstrate key subsystems, address key technical risks, and provide flight data to validate engineering models in representative flight environments. This is distinguished from certification flight testing, which is designed to formally validate system functionality and achieve flight readiness. Lessons learned from Saturn V, space shuttle, and other flight programs are examined along with key Ares I technical risks in order to provide insight into possible DFT strategies. A strategy for the first test flight of the Ares I, known as Ares I-1, is presented.

Kripke modelling approaches of a multiple robots system with minimalist communication: A formal approach of choice

Real-time, critical systems such as avionics software and hardware chips, owe their reliability to formal modelling approaches from their design phase. Following this philosophy, an intuitive yet mathematically rigorous approach of Kripke modelling is used for representing a co-operative, decentralised mobile robot group. The robot group operates with minimalist communication and no a priori knowledge of the operating environment for achieving interception and coordinated time-over-target. This scenario is a prototype of a simple task envisaged for a group of unmanned aerial vehicles (UAVs). As such, the resulting behaviour of the UAVs must be designed and analysed, so that guaranteed performance is ensured if only to achieve flight certification. Hence, there is a need for a mathematically rigorous approach, or a formal modelling technique. Several such techniques are briefly reviewed and it is argued that Kripke modelling is the best suited one. Kripke models consist of, firstly, a set of possible worlds (system configurations), secondly, an accessibility relation in the set (transitions between the worlds) and thirdly, a labelling function (which logical statements are true in each world). This approach represents continuous dynamics and discrete decision making of the robots in a unified way. Desirable properties of co-operation can be precisely expressed using temporal logic statements defining safety, liveness etc. Whether a group of robots, whose behaviour is formalised with Kripke models, possesses such properties is then verified using automated model checking tools. Rationale for this approach along with simulation and verification results are presented in the paper.

AN AIRBORNE EAS ARRAY TO ANALYSE THE KNEE ENERGY REGION

The knee energy region contains still several ambiguities in both aspects of primary composition and possible change in the standard description of multiple production. EAS are generally detected during the cascade absorption phase where the trigger by protons dominates. On the contrary, for EAS recorded at high altitude, the trigger initiated by heavy nuclei primaries turns to be the most efficient.1 The large area of the Airbus A380 and the exposure available during several thousand hours of certification flights suggests the opportunity of an airborne experiment at 10 – 12 km altitude to follow the different size spectra up to ~ 107 GeV. Some basic simulations are carried here to point out different criteria suitable to discriminate between heavy and light primaries.

Historical Overview of Research in Reconfigurable Flight Control

This article presents a historical overview of research in reconfigurable flight control. For the purpose of this article, the term ‘reconfigurable flight control’ is used to refer to software algorithms designed specifically to compensate for failures or damage of flight control effectors or lifting surfaces, using the remaining effectors to generate compensating forces and moments. This article will discuss initial research and flight testing of approaches based on explicit fault detection, isolation, and estimation, as well as later approaches based on continuously adaptive and intelligent control algorithms. In addition, approaches for trajectory reshaping of an impaired aircraft with reconfigurable inner loop control laws will be briefly discussed. Finally, there will be some discussion on current implementations of reconfigurable control to improve safety on production and flight test aircraft and remaining challenges to enable broader use of the technology, such as the difficulties of flight certification of these types of approaches.

‘RCHX-1-STORM’ first Slovenian meteorological rocket program

Astronautic and Rocket Society Celje (ARSC) formed a special working team for research and development of a small meteorological hail suppression rocket in the 70th. The hail suppression system was established in former Yugoslavia in the late 60th as an attempt to protect important agricultural regions from one of the summer's most vicious storm. In this time Slovenia was a part of Yugoslavia as one of the federal republic with relative high developed agricultural region production. The Rocket program ‘RCHX-STORM’ was a second attempt, for Slovenia indigenously developed in the production of meteorological hail suppression rocket. ARSC has designed a family of small sounding rocket that were based on highly promising hybrid propellant propulsion. Hybrid propulsion was selected for this family because it was offering low cost, save production and operation and simple logistics. Conventional sounding rockets use solid propellant motor for their propulsion. The introduction of hybrid motors has enabled a considerable decrease in overall cost. The transportation handling and storage procedures were greatly simplified due to the fact that a hybrid motor was not considered as explosive matter. A hybrid motor may also be designed to stand a severe environment without resorting to conditioning arrangements. The program started in the late 70th when the team ARSC was integrated in the Research and Development Institute in Celje (RDIC). The development program aimed to produce three types of meteorological rockets with diameters 76, 120 and 160 mm . Development of the RCHX-76 engine and rocket vehicle including flight certification has been undertaken by a joint team comprising of the ARCS, RDIC and the company Cestno podjetje Celje (CPC), Road building company Celje. Many new techniques and methods were used in this program such as computer simulation of external and internal ballistics, composite materials for rocket construction, intensive static testing of models and flight configuration with long flight-testing program. The main features of this project were discussed in this paper, summarizing the history of the development of the RCHX-STORM rockets family.

The Use of a Personal Computer-Based Aviation Training Device in Ab Initio Flight Training

A personal computer-based aviation training device (PCATD) was used to train 63 ab initio flight students. Thirty-nine foreign airline trainees and 24 students from the U.S. participated in approximately 10 hours of basic VFR training between the completion of their ground school course work and flight lessons. All PCATD training followed a strict syllabus and was instructor-led. After the completion of their PCATD training, students followed the traditional flight lesson syllabus and training performance was tracked up to private pilot certification. Dual flight hours prior to the first solo flight, landings prior to the first solo flight, dual flight hours between the first solo flight and private certification, and landings between the first solo flight and private certification provided dependent variables for this study. The results suggest that the PCATD training was effective in improving training performance for some students. Those most influenced were students who traditionally require substantially more training prior to solo and private certification than that called for by the syllabus used at the facility where this study was conducted. Results also indicate that, as expected, the PCATD exposure had the greatest impact on training performance prior to solo.

Flight test certification of multipurpose head-up display for general aviation aircraft

Advances in flight display technology have enabled manufacturers to provide a head-up display (HUD) of aircraft control and performance parameters for use in general aviation aircraft without the use of inertial platforms or specialized data bus architecture. The Federal Aviation Administration currently has no regulatory guidance regarding HUD or flight symbology certification. A specific certification pro- gram is presented. The process of categorizing the HUD as a supplemental system instead of a primary display is discussed. Flight display symbology is discussed, and the final symbology set is presented. The certification flight test plan is discussed including the requirements for functional, usability, and opera- tional testing. Flight test data are discussed. A HUD system was certified for single-pilot use in instrument meteorological conditions in a general aviation aircraft. HE head-up-displ ay (HUD) was first developed in mili- tary aircraft from reflecting optical sights. The HUD places flight and navigation data in the pilot's forward field of view (FOV). These data are presented through various symbols as a collimated image that appears to be floating at infinity. Early HUDs were used for weapons delivery with displays tailored for a single task. HUDs today can provide a variety of aircraft state and navigation data. Recent HUD develop- ment, as an enhancement tool to facilitate manually flown in- strument approaches to weather minima as low as a runway visual range of 1200 ft, has obvious implications for air carrier operations. The ability to ease the instrument-to-visual ap- proach transition and acquire the runway environment sooner is a desirable feature of any cockpit display system. Though these systems usually require high-fidelity inertial reference platforms and are costly, the advantage gained in arrival reli- ability has been deemed cost effective. Additionally, because the pilot has state and navigation data available while looking through the aircraft windscreen, the increased ability to visu- ally clear for other traffic is a safety enhancement. Current HUD development and operational concept are toward dis- plays that are useful and certifiable during all phases of flight. Lower cost displays that do not provide enhanced capability, but do provide increased out-of-the-cockpit awareness for cor- porate and general aviation aircraft are also emerging into the marketplace. A typical HUD displays airspeed, altitude, pitch and roll attitude, and heading. In addition, navigation or mission data can usually be selected for display. Flight director modes, radar altitude, and marker beacon passage can also be shown, if available. Most HUDs can also display master warning and caution annunciators. The subject HUD was targeted for the corporate and general aviation industry. This HUD differed from other operational systems in that it used conventional aircraft gyros and did not depend on an inertial navigation system platform for attitude information. Since conventional aircraft gyros are less precise than inertial platforms, the HUD symbology was not confor-

Flight test certification of primary category aircraft using TP101-41E sportplane design standard

This article discusses certification standards, flight testing, and type certification of a primary category aircraft using the Transport Canada TP101-41E Ultra-Light Design Standard as the certification basis. For many years manufacturers maintained that certification standards were overly restrictive with regard to small aircraft of simple design, and therefore, restrict growth and innovation in the small airplane industry. Government agencies in conjunction with industry set forth to design a streamlined certification standard for these type aircraft. The primary category rule for type certification of aircraft of simple design intended for pleasure or personal use was adopted. Presented is an overview of certification and flight test of the Quicksilver GT 500 aircraft that was certified under the primary rule using the Transport Canada TP101-41E Ultra-Light Design Standard. Certification flight test plans and flight test techniques used to gather data are presented. Flight test data and compliance with TP101-41E are discussed. Noncompliant findings are discussed. The Quicksilver GT 500, the first aircraft certified in the primary category, was awarded a provisional-type certificate on August 1, 1993.

NSTS Orbiter Auxiliary Power Unit Turbine Wheel Cracking Risk Assessment

The present investigation of turbine-wheel cracking problems in the hydrazine-fueled APU turbine wheel of the Space Shuttle Orbiter's Main Engines has indicated the efficacy of systematic probabilistic risk assessment in flight certification and safety resolution. Nevertheless, real crack-initiation and propagation problems do not lend themselves to purely analytical studies. The high-cycle fatigue problem is noted to generally be unsuited to probabilistic modeling, due to its extremely high degree of intrinsic scatter. In the case treated, the cracks appear to trend toward crack arrest in a low cycle fatigue mode, due to a detuning of the resonance model.

A Method of Studying Errors in Flight Crew Communication,

We present a method of studying errors in flight crew communication, based on the information-processing paradigm. The taxonomy of errors proposed here is based on two dimensions, Type of Communication Errors (Transmission, Detection, Identification, Interpretation, plus Action linked to communication), Type of Adjustment (Individual: problem-solving by the operator concerned; interactive: problem-solving by crew). This taxonomy, tested during certification flight test, seems to be useful in all work situations based on information exchange between operators.