IEC 62396-1:2016

IEC 62396-1 ®
Edition 2.0 2016-01
INTERNATIONAL
STANDARD
colour
inside
Process management for avionics – Atmospheric radiation effects –
Part 1: Accommodation of atmospheric radiation effects via single event effects
within avionics electronic equipment
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IEC 62396-1 ®
Edition 2.0 2016-01
INTERNATIONAL
STANDARD
colour
inside
Process management for avionics – Atmospheric radiation effects –

Part 1: Accommodation of atmospheric radiation effects via single event effects

within avionics electronic equipment

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 03.100.50; 31.020; 49.060 ISBN 978-2-8322-3078-7

– 2 – IEC 62396-1:2016  IEC 2016
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 9
2 Normative references . 9
3 Terms and definitions . 9
4 Abbreviations and acronyms . 18
5 Radiation environment of the atmosphere . 21
5.1 Radiation generation . 21
5.2 Effect of secondary particles on avionics . 21
5.3 Atmospheric neutrons . 21
5.3.1 General . 21
5.3.2 Atmospheric neutrons energy spectrum and SEE cross-sections . 22
5.3.3 Altitude variation of atmospheric neutrons . 24
5.3.4 Latitude variation of atmospheric neutrons . 25
5.3.5 Thermal neutrons within aircraft . 27
5.4 Secondary protons . 27
5.5 Other particles . 28
5.6 Solar enhancements . 29
5.7 High altitudes greater than 60 000 ft (18 290 m) . 29
6 Effects of atmospheric radiation on avionics . 30
6.1 Types of radiation effects . 30
6.2 Single event effects (SEEs) . 30
6.2.1 General . 30
6.2.2 Single event upset (SEU) . 31
6.2.3 Multiple bit upset (MBU) and multiple cell upset (MCU) . 31
6.2.4 Single effect transients (SETs) . 33
6.2.5 Single event latch-up (SEL) . 34
6.2.6 Single event functional interrupt (SEFI) . 34
6.2.7 Single event burnout (SEB) . 34
6.2.8 Single event gate rupture (SEGR) . 35
6.2.9 Single event induced hard error (SHE) . 35
6.2.10 SEE potential risks based on future technology . 35
6.3 Total ionising dose (TID) . 36
6.4 Displacement damage . 37
7 Guidance for system designs . 37
7.1 Overview. 37
7.2 System design . 40
7.3 Hardware considerations. 41
7.4 Electronic devices characterisation and control . 42
7.4.1 Rigour and discipline . 42
7.4.2 Level A systems . 42
7.4.3 Level B . 42
7.4.4 Level C . 43
7.4.5 Levels D and E . 43
8 Determination of avionics single event effects rates . 43

8.1 Main single event effects . 43
8.2 Single event effects with lower event rates. 44
8.2.1 Single event burnout (SEB) and single event gate rupture (SEGR) . 44
8.2.2 Single event transient (SET) . 44
8.2.3 Single event hard error (SHE) . 45
8.2.4 Single event latch-up (SEL) . 45
8.3 Single event effects with higher event rates – Single event upset data . 45
8.3.1 General . 45
8.3.2 SEU cross-section . 46
8.3.3 Proton and neutron beams for measuring SEU cross-sections . 46
8.3.4 SEU per bit cross-section trends in SRAMs . 50
8.3.5 SEU per bit cross-section trends and other SEE in DRAMs . 51
8.4 Calculating SEE rates in avionics . 53
8.5 Calculation of availability of full redundancy . 54
8.5.1 General . 54
8.5.2 SEU with mitigation and SET . 54
8.5.3 Firm errors and faults . 55
9 Considerations for SEE compliance . 55
9.1 Compliance . 55
9.2 Confirm the radiation environment for the avionics application . 55
9.3 Identify the system development assurance level . 55
9.4 Assess preliminary electronic equipment design for SEE . 55
9.4.1 Identify SEE-sensitive electronic components . 55
9.4.2 Quantify SEE rates . 55
9.5 Verify that the system development assurance level requirements are met
for SEE . 55
9.5.1 Combine SEE rates for the entire system . 55
9.5.2 Management of electronic components control and dependability . 56
9.6 Corrective actions . 56
Annex A (informative) Thermal neutron assessment . 57
Annex B (informative) Methods for calculating SEE rates in avionics electronics . 58
B.1 Proposed in-the-loop system test – Irradiating avionics LRU in
neutron/proton beam, with output fed into aircraft simulation computer . 58
B.2 Irradiating avionics LRU in a neutron/proton beam . 58
B.3 Utilising existing SEE data for specific electronic components on LRU . 59
B.3.1 Neutron proton data . 59
B.3.2 Heavy ion data . 60
B.4 Applying generic SEE data to all electronic components on LRU . 61
B.5 Component level laser simulation of single event effects . 62
B.6 Determination of SEU rate from service monitoring . 63
Annex C (informative) Review of test facility availability . 65
C.1 Facilities in the USA and Canada . 65
C.1.1 Neutron facilities . 65
C.1.2 Proton facilities . 66
C.1.3 Laser facilities . 68
C.2 Facilities in Europe . 69
C.2.1 Neutron facilities . 69
C.2.2 Proton facilities . 71
C.2.3 Laser facilities . 72

– 4 – IEC 62396-1:2016  IEC 2016
Annex D (informative) Tabular description of variation of atmospheric neutron flux
with altitude and latitude . 73
Annex E (informative) Consideration of effects at higher altitudes . 75
Annex F (informative) Prediction of SEE rates for ions . 80
Annex G (informative) Late news as of 2014 on SEE cross-sections applicable to the
atmospheric neutron environment . 83
G.1 SEE cross-sections key to SEE rate calculations . 83
G.2 Limitations in compiling SEE cross-section data. 83
G.3 Cross-section measurements (figures with data from public literature) . 84
G.4 Conservative estimates of SEE cross-section data . 84
G.4.1 General . 84
G.4.2 Single event upset (SEU) . 85
G.4.3 Multiple cell upset (MCU) . 87
G.4.4 Single event functional interrupt (SEFI) . 88
G.4.5 Single event latch-up (SEL) . 89
G.4.6 Single event transient (SET) . 91
G.4.7 Single event burnout (SEB) . 92
Annex H (informative) Calculating SEE rates from non-white (non-atmospheric like)
neutron cross-sections for small geometry electronic components . 94
H.1 Energy thresholds . 94
H.2 Nominal neutron fluxes . 94
H.3 Calculating event rates using non-atmospheric like cross-sections for small
geometry electronic devices . 95
Bibliography . 96

Figure 1 – Energy spectrum of atmospheric neutrons at 40 000 ft (12 160 m), latitude
45° . 22
Figure 2 – Model of the atmospheric neutron flux variation with altitude (see Annex D) . 25
Figure 3 – Distribution of vertical rigidity cut-offs around the world . 26
Figure 4 – Model of atmospheric neutron flux variation with latitude . 26
Figure 5 – Energy spectrum of protons within the atmosphere . 28
Figure 6 – System safety assessment process . 38
Figure 7 – SEE in relation to system and LRU effect . 40
Figure 8 – Variation of RAM SEU cross-section as function of neutron/proton energy . 48
Figure 9 – Neutron and proton SEU bit cross-section data . 49
Figure 10 – SEU cross-section in SRAMs as function of the manufacture date . 51
Figure 11 – SEU cross-section in DRAMs as function of manufacture date . 52
Figure E.1 – Integral linear energy transfer spectra in silicon at 100 000 ft (30 480 m)
for cut-off rigidities (R) from 0 GV to 17 GV . 76
Figure E.2 – Integral linear energy transfer spectra in silicon at 75 000 ft (22 860 m) for
cut-off rigidities (R) from 0 to 17 GV . 76
Figure E.3 – Integral linear energy transfer spectra in silicon at 55 000 ft (16 760 m) for
cut-off rigidities (R) from 0 GV to 17 GV . 77
Figure E.4 – Influence of solar modulation on integral linear energy transfer spectra in
silicon at 150 000 ft (45 720 m) for cut-off rigidities (R) of 0 GV and 8 GV . 77
Figure E.5 – Influence of solar modulation on integral linear energy transfer spectra in
silicon at 55 000 ft (16 760 m) for cut-off rigidities (R) of 0 GV and 8 GV . 78

Figure E.6 – Calculated contributions from neutrons, protons and heavy ions to the
SEU rates of the Hitachi-A 4 Mbit SRAM as a function of altitude at a cut-off rigidity (R)
of 0 GV . 79
Figure E.7 – Calculated contributions from neutrons, protons and heavy ions to the
SEU rates of the Hitachi-A 4 Mbit SRAM as a function of altitude at a cut-off rigidity
(R) of 8 GV . 79
Figure F.1 – Example differential LET spectrum . 81
Figure F.2 – Example integral chord length distribution for isotropic particle
environment . 81
Figure G.1 – Variation of the high energy neutron SEU cross-section per bit as a
function of electronic device feature size for SRAMs and SRAM arrays in
microprocessors and FPGAs . 85
Figure G.2 – Variation of the high energy neutron SEU cross-section per bit as a

function of electronic device feature size for DRAMs . 86
Figure G.3 – Variation of the high energy neutron SEU cross-section per electronic
device as a function of electronic device feature size for NOR and NAND type flash
memories . 87
Figure G.4 – Variation of the MCU/SBU percentage as a function of feature size based
on data from many researchers in SRAMs [43, 45] . 88
Figure G.5 – Variation of the high energy neutron SEFI cross-section in DRAMs as a
function of electronic device feature size . 89
Figure G.6 – Variation of the high energy neutron SEFI cross-section in
microprocessors and FPGAs as a function of electronic device feature size . 90
Figure G.7 – Variation of the high energy neutron single event latch-up (SEL) cross-
section in CMOS devices (SRAMs, processors) as a function of electronic device
feature size . 91
Figure G.8 – Single event burnout (SEB) cross-section in power electronic devices
(400 V to 1 200 V) as a function of drain-source voltage (V ) . 92
DS
Table 1 – Nomenclature cross reference . 39
Table B.1 – Sources of high energy proton or neutron SEU cross-section data . 60
Table B.2 – Some models for the use of heavy ion SEE data to calculate proton SEE
data . 61
Table D.1 – Variation of 1 MeV to 10 MeV neutron flux in the atmosphere with altitude . 73
Table D.2 – Variation of 1 MeV to 10 MeV neutron flux in the atmosphere with latitude . 74
Table G.1 – Information relevant to neutron-induced SET . 92
Table H.1 – Approximate SEU energy thresholds for SRAM-based devices. 94
Table H.2 – Neutron fluxes above different energy thresholds (40 000 ft, latitude 45°) . 94

– 6 – IEC 62396-1:2016  IEC 2016
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PROCESS MANAGEMENT FOR AVIONICS –
ATMOSPHERIC RADIATION EFFECTS –

Part 1: Accommodation of atmospheric radiation effects via
single event effects within avionics electronic equipment

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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6) All users should ensure that they have the latest edition of this publication.
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62396-1 has been prepared by IEC technical committee 107:
Process management for avionics.
This second edition cancels and replaces the first edition published in 2012. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) removed, in Clause 7 related to system design, reference to level A Type I and Type II
(system and references). As Clause 7 is now for guidance, ”shall” statements have been
changed to “should” and in 9.5.2 the requirement for electronic component management is
clarified;
b) all current definitions included in Clause 3 are those used within the IEC 62396 family of
documents;
c) incorporated in Annex G related to new technology or latest news reference to some new
papers and issues which have appeared since 2011;
d) solar flares and extreme space weather reference added in 5.6 to a proposed future
Part 6;
e) reference added in 7.1 to a proposed new Part 7 on incorporating atmospheric radiation
effects analysis into the system design process;
f) reference added in 6.2.10 d) to a proposed future Part 8 on other particles including
protons, pions and muons;
g) clarification on calculating event rates where cross-sections have been obtained with non-
atmospheric radiation like neutron sources, addition of a new Annex H, and changes to 5.3
and 8.2.
The text of this standard is based on the following documents:
FDIS Report on voting
107/271/FDIS 107/275/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all the parts in the IEC 62396 series, published under the general title Process
management for avionics – Atmospheric radiation effects, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC website under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
– 8 – IEC 62396-1:2016  IEC 2016
INTRODUCTION
This industry-wide International Standard informs avionics systems designers, electronic
equipment manufacturers, component manufacturers and their customers of the kind of
ionising radiation environment that their devices will be subjected to in aircraft, the potential
effects this radiation environment can have on those devices, and some general approaches
for dealing with these effects.
The same atmospheric radiation (neutrons and protons) that is responsible for the radiation
exposure that crew and passengers acquire while flying is also responsible for causing the
single event effects (SEE) in the avionics electronic equipment. There has been much work
carried out over the last few years related to the radiation exposure of aircraft passengers and
crew. A standardised industry approach on the effect of the atmospheric neutrons on
electronics should be viewed as consistent with, and an extension of, the on-going activities
related to the radiation exposure of aircraft passengers and crew.
Atmospheric radiation effects are one factor that could contribute to equipment hard and soft
fault rates. From a system safety perspective, using derived fault rate values, the existing
methodology described in ARP4754A (accommodation of hard and soft fault rates in general)
will also accommodate atmospheric radiation effect rates.
In addition, this International Standard refers to the JEDEC Standard JESD 89A, which relates
to soft errors in electronics by atmospheric radiation at ground level (at altitudes less than
10 000 ft (3 040 m)).
PROCESS MANAGEMENT FOR AVIONICS –
ATMOSPHERIC RADIATION EFFECTS –

Part 1: Accommodation of atmospheric radiation effects via
single event effects within avionics electronic equipment

1 Scope
This part of IEC 62396 is intended to provide guidance on atmospheric radiation effects on
avionics electronics used in aircraft operating at altitudes up to 60 000 ft (18,3 km). It defines
the radiation environment, the effects of that environment on electronics and provides design
considerations for the accommodation of those effects within avionics systems.
This International Standard is intended to help avionics equipment manufacturers and
designers to standardise their approach to single event effects in avionics by providing
guidance, leading to a standard methodology.
Details of the radiation environment are provided together with identification of potential
problems caused as a result of the atmospheric radiation received. Appropriate methods are
given for quantifying single event effect (SEE) rates in electronic components. The overall
system safety methodology should be expanded to accommodate the single event effects
rates and to demonstrate the suitability of the electronics for the application at the component
and system level.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC TS 62239-1:2015, Process management for avionics – Management plan – Part 1:
Preparation and maintenance of an electronic components management plan
IEC 62396-2:2012, Process management for avionics – Atmospheric radiation effects –
Part 2: Guidelines for single event effects testing for avionics systems
IEC 62396-3, Process management for avionics – Atmospheric radiation effects – Part 3:
System design optimization to accommodate the single event effects (SEE) of atmospheric
radiation
IEC 62396-4:2013, Process management for avionics – Atmospheric radiation effects –
Part 4: Design of high voltage aircraft electronics managing potential single event effects
IEC 62396-5, Process management for avionics – Atmospheric radiation effects – Part 5:
Assessment of thermal neutron fluxes and single event effects in avionics systems
EIA-4899, Standard for Preparing an Electronic Components Management Plan
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

– 10 – IEC 62396-1:2016  IEC 2016
NOTE Users of this international standard can use alternative definitions consistent with convention within their
companies.
3.1
aerospace recommended practice
documents relating to avionics which are published by the Society of Automotive Engineers
(SAE)
3.2
analogue single event transient
ASET
spurious signal or voltage produced at the output of an analogue component by the deposition
of charge by a single particle
3.3
availability
probability that a system is working at instant t, regardless of the number of times it may have
previously failed and been repaired
Note 1 to entry: For equipment, availability is the fraction of time the equipment is functional divided by the total
time the equipment is expected to be operational, i.e. the time the equipment is functional plus any repair time.
3.4
avionics equipment environment
applicable environmental conditions (as described per the
equipment specification) that the equipment is able to withstand without loss or degradation in
equipment performance during all of its manufacturing cycle and maintenance life
Note 1 to entry: The length of the maintenance life is defined by the equipment manufacturer in conjunction with
customers.
3.5
capable
ability of a component to be used successfully in the intended application
3.6
certified
assessed and compliant to an applicable standard, with maintenance of a certificate and
registration
3.7
characterisation
process of testing a sample of components to determine the key electrical parameter values
that can be expected of all produced components of the type tested
3.8
component application
process that assures that the component meets the design requirements of the equipment in
which it is used
3.9
component manufacturer
organisation responsible for the component specification and its production
3.10
could not duplicate
CND
reported outcome of diagnostic testing on a piece of equipment
Note 1 to entry: Following receipt of an error or fault message during operation, the error or fault condition could
not be replicated during subsequent equipment testing (see IEC 62396-3).

3.11
critical charge
smallest charge that will cause an SEE if injected or deposited in the sensitive volume
Note 1 to entry: For many electronic components, the unit applied is the pico coulomb (pC); however, for small
geometry components, this parameter is measured in femto coulomb (fC).
3.12
cross-section
σ
combination of sensitive area and probability of an
interaction depositing the critical charge for a SEE
Note 1 to entry: The cross-section may be calculated using the following formula:
σ = number of errors/particle fluence
Note 2 to entry: The units for cross-section are cm per electronic component or per bit.
3.13
double error correction triple error detection
DECTED
system or equipment methodology to test a digital word of information to determine if it has
been corrupted, and if corrupted, to conditionally apply a correction
Note 1 to entry: This methodology can correct two-bit corruptions and can detect and report three-bit corruptions.
(Used within IEC 62396-3.)
3.14
digital single event transient
DSET
spurious digital signal or voltage, induced by the deposition of charge by a single particle that
can propagate through the circuit path during one clock cycle
Note 1 to entry: See 6.2.4.
3.15
electron
elementary particle having a mass of approximately 1/1 840 atomic mass units, and a
–19
negative charge of 1,602 × 10 C
3.16
electronic components management plan
ECMP
equipment manufacturer's document that defines the processes and practices for applying
electronic components to an equipment or range of equipment
Note 1 to entry: Generally, it addresses all relevant aspects of the controlling components during system design,
development, production, and post-production support.
3.17
electronic component
electrical or electronic device that is not subject to disassembly without destruction or
impairment of design use
EXAMPLE Resistors, capacitors, diodes, integrated circuits, hybrids, application specific integrated circuits,
wound components and relays.
Note 1 to entry: An electronic component is sometimes called electronic device, electronic part, or piece part.
3.18
electronic equipment
item produced by the equipment manufacturer, which incorporates electronic components

– 12 – IEC 62396-1:2016  IEC 2016
EXAMPLE End items, sub-assemblies, line-replaceable units and shop-replaceable units.
3.19
electronic flight instrumentation system
EFIS
avionics electronic system requiring system development assurance level A and for which the
pilot will be within the loop (within the control loop) through the pilot/system information
exchange
3.20
expert
person who has demonstrated competence to apply knowledge and skill to the specific
subject
3.21
firm error
circuit cell failure within an electronic component that cannot be
reset other than by rebooting the system or by cycling the power
Note 1 to entry: Such a failure can manifest itself as a soft fault in that it could provide no fault found during
subsequent test and impact the value for the MTBUR of the LRU.
Note 2 to entry: See also soft error.
3.22
firm fault
failure that cannot be reset other than by rebooting the system or by
cycling the power to the relevant functional element
Note 1 to entry: Such a fault can impact the value for the MTBF of the LRU and provide no fault found during the
subsequent test.
3.23
fly-by-wire
FBW
avionics electronic system requiring system development assurance level A and for which the
pilot will not be within the aircraft stability control loop
3.24
functional hazard assessment
FHA
assessment of all hazards against a set of defined hazard classes
3.25
giga electron volt
GeV
volts, that is,
energy gained when an electron is accelerated by an electric potential of 10
radiation particle energy of giga electron volts (thousand million electron volts)
Note 1 to entry: The SI equivalent energy is 160,2 pico joules.
3.26
gray
Gy
SI unit of ionising radiation dose, defined as the absorption of one joule (J) of radiation energy
per one kilogram (kg) of matter
Note 1 to entry: Related units are centigray (cGy) and rad. 1 cGy is equal to 1 rad.

3.27
hard error
permanent or semi-permanent damage of a cell by atmospheric radiation that is not
recoverable even by cycling the power off and on
Note 1 to entry: Hard errors can include SEB, SEGR and SEL. Such a fault would be manifest as a hard fault and
can impact the value for the MTBF of the LRU.
3.28
hard fault
permanent failure of a component within an LRU
Note 1 to entry: A hard fault results in the removal of the LRU affected and the replacement of the permanently
damaged component before a system/system architecture can be restored to full functionality. Such a fault can
impact the value for the MTBF of the LRU repaired.
3.29
heavy ion
positively charged nucleus of the elements heavier than hydrogen and helium
3.30
in-the-loop
test methodology where an LRU is placed within a radiation beam that provides a simulation
of the atmospheric neutron environment and where the inputs to the LRU can be from an
electronic fixture external to the beam to enable a closed loop system
Note 1 to entry: The electronic fixture can contain a host computer for the aircraft simulation model. The
electronic fixture can also contain appropriate signal conditioning for compatibility with the LRU. In the case of an
automatic control function, the outputs from the LRU can be, in turn, sent to an actuation means or directly to the
host computer. The host computer would automatically close a stability loop (as in the case of a fly-by-wire control
system). In the case of a navigation function, the outputs from the LRU could be sent to a display system where the
pilot could then close the navigation loop.
3.31
integrated modular avionics
IMA
implementation of aircraft functions in a multitask computing environment where the
computations for each specific system implementing a particular function are confined to a
partition that is executed by a common computing resource (a single digital electronic circuit)
3.32
latch-up
triggering of a parasitic p-n-p-n circuit in bulk CMOS, resulting in a state where the parasitic
latched current exceeds the holding current
Note 1 to entry: This state is maintained while power is applied.
Note 2 to entry: Latch-up can be a particular case of a soft fault (firm/soft error) or in the case where it causes
electronic component damage, a hard fault.
3.33
linear energy transfer
LET
energy deposited per unit path length in a semiconductor along the path of the radiation
Note 1 to entry: The units applicable are MeV⋅cm /mg.
3.34
linear energy transfer threshold
LET
th
for a given component, the minimum LET to cause an effect at a particle fluence of
7 –2
ions⋅cm
1 × 10
– 14 – IEC 62396-1:2016  IEC 2016
3.35
line replaceable unit
LRU
piece of equipment that may be replaced during the maintenance cycle of the system
3.36
mega electron volt
MeV
energy gained when an electron is accelerated by an electric potential of 10 volts, that is,
radiation particle energy of mega electron volts (million electron volts)
Note 1 to entry: The SI equivalent energy is 160,2 femto joule.
3.37
mean time between failure
MTBF
measure of reliability, which is the mean time between failure of equipment or a system in
service
Note 1 to entry: MTBF is a term from the world airlines’ technical glossary referring to the mean time between
failure of equipment or a system in service such that it generally requires the replacement of a damaged
component before a system/system architecture can be restored to full functionality and thus it is a measure of
reliabil
...