Makes Safety Recommendations To The FAA On Glass Cockpits
March 29, 2010 - The National Transportation Safety Board adopted a study and concluded that small aircraft that had “glass cockpits” were not safer and had a higher fatal accident rate then similar aircraft with conventional instruments.
As a result the NTSB has proposed safety recommendations to the Federal Aviation Administration (FAA) and has requested the FAA respond within 90 days in addressing the actions taken or intends to take to implement the Board's recommendations.
The Board has recommended (in brief) that airman knowledge tests include questions regarding electronic flight and navigation displays. Training materials should cover electronic primary flight displays, initial and recurrent flight proficiency requirements should include flight displays requirements for pilots, as well develop and publish guidance for the use of equipment-specific.
In addition, recommendations call for requiring all manufacturers to include in their approved aircraft flight manual and pilot’s operating handbook supplements information regarding abnormal equipment operation or malfunction due to subsystem and input malfunctions, including but not limited to pitot and/or static system blockages, magnetic sensor malfunctions, and attitude-heading reference system alignment failures. Below is the actual report submitted to the FAA on March 29, 2010.
National Transportation Safety Board Safety
Honorable J. Randolph Babbitt ,
,Administrator Federal Aviation Administration
supporting these recommendations is discussed in this letter and in the
safety study. The NTSB would appreciate a response from you within 90
days addressing the actions you have taken or intend to take to
implement our recommendations.
In a span of only
a few years, the cockpits of light aircraft have undergone a transition
from conventional flight instruments to integrated, computerized
displays commonly referred to as glass cockpits. This change has
occurred rapidly. Data from the General Aviation Manufacturers
Association (GAMA) indicate that by 2006, more than 90 percent of new
piston-powered, light airplanes were equipped with full glass cockpit
displays. Several manufacturers of glass cockpit displays now produce
displays with supplemental type certification for retrofit installation
in existing aircraft, suggesting that the number of aircraft equipped
with full glass cockpits will continue to grow.
of this advanced technology into light aircraft has brought with it a
new set of potential safety concerns, including equipment design and
operation; pilot performance and training; and new accident
This study was
designed to test the hypothesis that the transition to glass cockpit
avionics in light aircraft would improve the safety of their operation.
The study also sought to evaluate the adequacy of resources and
requirements supporting the transition to this new technology. To
accomplish these goals, this study included three separate analyses, as
described in the study report:
statistical analysis of accidents and activity data from two cohorts of
recently manufactured airplanes produced with and without electronic
PFDs, conducted to measure differences in activity, accident rates, and
accident circumstances between glass cockpit and conventional aircraft.
review of FAA and industry training resources and requirements related
to glass cockpit displays conducted to characterize the training and
identify areas for potential safety improvement.
A review of
accident case studies conducted to identify emerging safety issues
associated with the introduction of glass cockpit displays into this
class of aircraft.
Involvement and Accident Rates
The safety study
compared a defined group of glass cockpit aircraft and a cohort of the
same makes/models of aircraft with conventional instruments to reduce
the potential for confounds associated with comparing aircraft of
different age and capability. The study also used data from the FAA’s
General Aviation and Air Taxi Activity and Avionics (GAATAA) Survey to
make additional comparisons between aircraft using activity-based
accident rates that reflect accident risk.
showed that glass cockpit-equipped aircraft experienced proportionately
fewer total accidents than a comparable group of aircraft with
conventional round-dial instruments. The fact that accident rates were
higher for conventionally equipped aircraft than for glass cockpit
aircraft might suggest a safety benefit resulting from the new
technology—were it not for the fact that the study’s analyses also
showed that the glass cockpit cohort had a significantly higher
percentage of fatal accidents during the years 2002 through 2008 and
that the fatal accident rate per 100,000 flight hours observed for this
cohort in 2006 and 2007 was also higher. Data from the FAA’s GAATAA
Survey confirmed that differences in the activity and usage of the two
cohorts had likely influenced the type and severity of accidents
experienced by each group.
When considered as
a whole, the study results describe two distinct aircraft operational
profiles. Aircraft with conventional cockpit displays were more likely
to be used for flight instruction. Accordingly, these aircraft were also
found to have flown more hours per aircraft8 although they were used for
shorter flights9 and flew less time in instrument conditions. As a
result, aircraft in the conventional group were involved in more
accidents during takeoffs and landings, which often resulted in less
severe outcomes, most likely due to the relatively low speeds during
those phases and the resulting low impact forces.
operational profile of glass cockpit-equipped aircraft was found to
involve fewer flight hours per year but longer trips. Consequently, the
glass cockpit-equipped aircraft reportedly spent more time than
conventional aircraft operating on instrument flight plans. The accident
record is consistent with the way the aircraft were reportedly used.
Glass cockpit aircraft experienced more accidents while on long trips
and in instrument meteorological conditions (IMC) but also were reported
as spending more time operating in instrument conditions.
research has identified a higher risk of aircraft on longer flights
being involved in weather-related accidents and has noted that accidents
occurring in IMC are more likely to be fatal due to the event profiles
and impact forces typically associated with such accidents. The glass
cockpit cohort experienced higher fatal accident rates and higher
accident rates in IMC than the conventional aircraft—despite the fact
that the pilots had higher levels of certification, were more likely to
be instrument rated, had more total flight experience, and had more
experience in the aircraft type.
Based on the
pattern of study results, the NTSB concluded that study analyses of
aircraft accident and activity data showed a decrease in total accident
rates but an increase in fatal accident rates for the selected group of
glass cockpit aircraft when compared to similar conventionally equipped
aircraft during the study period. Overall, study analyses did not show a
significant improvement in safety for the glass cockpit study group.
Despite efforts on
the part of the FAA to develop resources and update training materials
to address the needs of pilots transitioning to glass cockpit aircraft,
the study identified several safety issues and areas for improvement.
knowledge tests, for example, do not currently assess pilots’ knowledge
of glass cockpit displays. The NTSB concluded that pilots must be able
to demonstrate a minimum knowledge of primary aircraft flight
instruments and displays in order to be prepared to safely operate
aircraft equipped with those systems, which is necessary for all
aircraft but is not currently addressed by FAA knowledge tests for glass
cockpit displays. The NTSB therefore recommends that the FAA revise
airman knowledge tests to include questions regarding electronic flight
and navigation displays, including normal operations, limitations, and
the interpretation of malfunctions and aircraft attitudes.
The NTSB’s review
of the FAA’s training initiatives showed that the FAA worked with
representatives from the general aviation industry and academia to
develop its FAA Industry Training Standards (FITS) initiative in
response to a recognized need for improved training for advanced
aircraft systems. Initial planning documents show that although the FITS
initiative intended to combine teaching techniques, such as
scenario-based training, with requirements for equipment-specific
training, the FAA has not implemented the equipment-specific training
requirements suggested in the original FITS program documents.
with Information About Display Operation and Limitations
considered several accident case studies that highlighted the complexity
and unique functionality of glass cockpit displays in comparison to
conventional instruments, as well as potential safety-critical issues
associated with the design and operation of software-based systems. The
case studies illustrate the importance of pilots’ receiving sufficient
information about system operations and limitations so that they are
prepared to identify and safely respond to system malfunctions and
The pilot involved
in an accident on April 9, 2007, in
The NTSB concluded
that pilots are not always provided all of the information necessary to
adequately understand the unique operational and functional details of
the PFDs in their airplanes. Therefore, the NTSB recommends that the FAA
require all manufacturers of certified electronic PFDs to include
information in their approved aircraft flight manual and pilot’s
operating handbook supplements regarding abnormal equipment operation or
malfunction due to subsystem and input malfunctions, including but not
limited to pitot and/or static system blockages, magnetic sensor
malfunctions, and attitude-heading reference system alignment failures.
equipment becomes more complex, the demands placed on pilots to manage
and monitor equipment operation will continue to increase. Findings of
the FAA’s 2009 Part 23 - Small Airplane Certification Process Study, and
comments included in pertinent draft FAA advisory circulars, suggest
that the human-equipment interaction issues for Part 25
transport-category aircraft will become increasingly critical for Part
In contrast to the
generalized training traditionally required to operate the relatively
simple systems in Part 23 aircraft, the complexity and variation of Part
25 aircraft systems have been addressed by requiring pilots to hold a
type rating to act as pilot-in-command.14 However, now that light
aircraft are incorporating integrated glass cockpit avionics that rival
in complexity those in Part 25 aircraft, generalized systems training
may not be sufficient for pilots of these aircraft.
architectures require different operating techniques, and responses to
failure and knowledge of one type of glass cockpit display are not
likely to transfer to other systems. The NTSB concluded that generalized
guidance and training are no longer sufficient to prepare pilots to
safely operate glass cockpit avionics; effective pilot instruction and
evaluation must be tailored to specific equipment.
NTSB recommends that the FAA incorporate training elements regarding
electronic PFDs into its training materials and aeronautical knowledge
requirements for all pilots. The NTSB also recommends that the FAA
incorporate training elements regarding electronic PFDs into its initial
and recurrent flight proficiency requirements for pilots of 14 CFR Part
23 certified aircraft equipped with those systems that address
variations in equipment design and operation of such displays.
To be adequately
prepared to respond to flight instrument system malfunctions and
failures, pilots should be trained to identify and respond to all
anticipated failure modes. However, in many cases it is neither
appropriate nor practical to train for all anticipated types of glass
cockpit avionics failures and malfunctions in the aircraft. The NTSB
concluded that simulators or procedural trainers are the most practical
alternative means of training pilots to identify and respond to glass
cockpit avionics failures and malfunctions that cannot be easily or
safely replicated in light aircraft.
Pilots who do not
have ready access to approved flight simulators or training devices
could benefit from equipment-specific training using software
applications or procedural trainers that replicate glass cockpit
displays. Therefore, the NTSB recommends that the FAA develop and
publish guidance for the use of equipment-specific electronic avionics
display simulators and procedural trainers that do not meet the
definition of flight simulation training devices prescribed in 14 CFR
Part 60 to support equipment-specific pilot training requirements.
Difficulties and Equipment Malfunctions
investigations have revealed multiple instances of glass cockpit
avionics malfunctions that were not required to be reported to the FAA
and that did not result in a service difficulty report (SDR). Findings
of the FAA Part 23 - Small Airplane Certification Process Study suggest
a general difficulty with tracking Part 23 equipment performance due to
SDR system underreporting for light aircraft.
The NTSB concluded that identification and tracking of service difficulties, equipment malfunctions or failures, abnormal operations, and other safety issues will be increasingly important as light aircraft avionics systems and equipment continue to increase in complexity and variation of design, and current reporting to the FAA’s SDR system does not adequately capture this information for 14 CFR Part 23 certified aircraft used in general aviation operations.
The NTSB also concluded that the FAA’s current review of the 14 CFR Part 23 certification process provides an opportunity to improve upon deficiencies in the reporting of equipment malfunctions and defects identified by the FAA and aviation industry representatives in the July 2009 Part 23 - Small Airplane Certification Process Study.
However, the review of 14 CFR Part 23 and resulting regulatory actions will likely require considerable time. Therefore, to improve the voluntary submissions to the FAA SDR system in the interim, the NTSB recommends that the FAA inform aircraft and avionics maintenance technicians about the critical role of voluntary SDR system reports involving malfunctions or defects associated with electronic primary flight, navigation, and control systems in 14 CFR Part 23 certified aircraft used in general aviation operations.
The results of this study suggest that, for the aircraft and time period studied, the introduction of glass cockpit PFDs has not yet resulted in the anticipated improvement in safety when compared to similar aircraft with conventional instruments. Advanced avionics and electronic displays can increase the safety potential of general aviation aircraft operations by providing pilots with more operational and safety-related information and functionality, but more effort is needed to ensure that pilots are prepared to realize that potential. Adoption of uniform training elements by the FAA to ensure pilots have adequate knowledge of aircraft equipment operation and malfunctions, as well as improved reporting of equipment malfunctions and service difficulties, is likely to improve the safety of general aviation operations beyond those involving aircraft with glass cockpit displays. However, such actions are particularly important in order to achieve the potential safety benefits associated with advanced cockpit technologies in light aircraft.
Therefore, the National Transportation Safety Board recommends that the Federal Aviation Administration:
· Revise airman knowledge tests to include questions regarding electronic flight and navigation displays, including normal operations, limitations, and the interpretation of malfunctions and aircraft attitudes. (A-10-36)
· Require all manufacturers of certified electronic primary flight displays to include information in their approved aircraft flight manual and pilot’s operating handbook supplements regarding abnormal equipment operation or malfunction due to subsystem and input malfunctions, including but not limited to pitot and/or static system blockages, magnetic sensor malfunctions, and attitude-heading reference system alignment failures. (A-10-37)
· Incorporate training elements regarding electronic primary flight displays into your training materials and aeronautical knowledge requirements for all pilots. (A-10-38)
· Incorporate training elements regarding electronic primary flight displays into your initial and recurrent flight proficiency requirements for pilots of 14 Code of Regulations Part 23 certified aircraft equipped with those systems that address variations in equipment design and operations of such displays. (A-10-39)
· Develop and publish guidance for the use of equipment-specific electronic avionics display simulators and procedural trainers that do not meet the definition of flight simulation training devices prescribed in 14 Code of Federal Regulations Part 60 to support equipment-specific pilot training requirements. (A-10-40)
· Inform aircraft and avionics maintenance technicians about the critical role of voluntary service difficulty reporting system reports involving malfunctions or defects associated with electronic primary flight, navigation, and control systems in 14 Code of Federal Regulations Part 23 certified aircraft used in general aviation operations. (A-10-41)
In response to the recommendations in this letter, please refer to Safety Recommendations A-10-36 through -41. If you would like to submit your response electronically rather than in hard copy, you may send it to the following e-mail address: email@example.com. If your response includes attachments that exceed 5 megabytes, please e-mail us asking for instructions on how to use our secure mailbox. To avoid confusion, please use only one method of submission (that is, do not submit both an electronic copy and a hard copy of the same response letter).
Chairman HERSMAN, Vice Chairman HART, and Member SUMWALT concurred in these recommendations.
By: Deborah A.P. Hersman, Chairman
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