Showing posts with label Commercial Aviation. Show all posts
Showing posts with label Commercial Aviation. Show all posts

Monday, December 21, 2015

UNCERTAINTIES OF THE QZ8501 INVESTIGATION

Hello World,

After a wait for almost a year after the QZ8501 accident, the final investigation report was released recently. The report indicates the cumulative effects of mechanical/system failures and pilot action as the cause of the accident. However, the report attributes pilot-action as the major cause of the accident. I looked up a few documents and the story seems to be something more than what’s being thrown at us in the form of official conclusion. In this post, I wish to look into the uncovered/ignored aspects of the investigation. Based on my understanding of the facts [as released] and further research, there were system inadequacies that forced the flight crew to attempt over-riding system-driven flight protocols and their efforts could not be completed on time, due to which the aircraft went down with the crew and passengers.

Findings of the Investigation:

Exhibit A:
Oddity 1:
Cracking of a solder-joint [of both channels] leading to a loss of electrical continuity indicates the electrical side of failure I had already warned of in my previous post on the accident. If there is no electrical supply to the system, the system will remain inactive unless it is powered by a back-up power line. 
The ambiguity that stands out to me is:

Was it ‘one’ solder joint that connected both channels [A&B]? 
Or
Was it ‘one’ solder joint for channel A and ‘one’ solder joint for channel B? [Both channels connected to the RTLU separately]

If it were two solder joints, one for each channel, then it should be two separate failures in which case the relationship between the two needs to be ascertained. 

If it was just one solder joint that connected channel A with channel B, then it is clear that the system did not have the needed electrical redundancy, indicating a serious design flaw considering the key flight-critical status of the equipment [the flight came to an end because this failed].

Irrespective of the real nature of the finding, the questions that remain are:
Why is ambiguity being installed in the very beginning of an accident report? 
Also failures such as these are usually a sequence of events. 
If the investigation could go the level of solder-joint failure, what led to the failure of the solder-joint? 
What type of load on the joint increase that it had to fail? 
Why is that side of the failure not being discussed in the report?

Oddity 2:
An ‘unresolved repetitive fault’ occurred 4 times during the flight and the responses registered indicated that the 4th response was not in accordance to that of the message. 

The question that stands out is:

For the first three times, the repetitive fault did not subside or revert based on the ‘message-compliant’ responses from the flight crew. 

Why is this not being discussed in the report?

If the procedural response fails to provide the relief for a crisis situation, the failure needs to be attributed to the ‘Non-fail-Safe’ nature of the system [a design flaw]. If the flight crew did not get the result of ‘message-compliant’ responses, then it is natural for them to resort to out-of-procedure efforts to resolve the crisis as the flight of the aircraft was in deterioration when such off-procedure input was given by the flight crew.

Why hasn’t the report indicated the ‘state of vulnerability’ of the platform?

My Findings 

Exhibit B1:


I came across this patent where the inventor has granted the assignment to Airbus Operations SAS [Assignee on the patent]. Now Airbus is the manufacturer of QZ8501 that went down. This patent, deals with the process for limiting the steering angle of control surfaces. 

The movable parts of an aircraft [the airframe to be specific], visible from the outside, apart from the doors and landing gear are the control surfaces [These are found on the wings, tail-plane and tail-fin]. These are used to control the aircraft’s flight at all times. 

This patent covers the process to control steering angle for control surfaces, specifically the rudder [the one on the tail fin that stands upright on the tail-end of an airplane].

Here’s Exhibit B2:


This description shown above clearly indicates the significance of the technology covered in this patent. Engine failure is being used as an example of abnormal flight condition and the observation describes the way an aircraft will behave when an engine fails. 

As per this observation, the rudder, the control surface on the tail-fin of an airplane will be required to bring back the aircraft to the flight line when an engine fails and the aircraft gets destabilized.  Through this observation, the patent implies, that the rudder will need higher steering clearance so it can produce the force necessary to bring the aircraft back to its flight line [control the destabilization faced by the aircraft].

Here’s Exhibit B3:


As shown in the figure above, the patent moves on to describe the traditional system’s inability to restrict the pilot from sending several commands. This indicates the intent of this technology/process as something related to restricting pilot activity in operating control surfaces under certain ‘abnormal conditions.’

Here’s Exhibit B4:


The patent then describes the outcome of such abnormal conditions when the pilot is allowed to send multiple commands to the rudder, will lead to dangerous failure modes. The patent specifically mentions that the tail-fin may break under these conditions. 

Now look at this picture below.

Exhibit C:

http://redwiretimescom.r.worldssl.net/wp-content/uploads/2015/01/redwire-singapore-air-asia-qz8501-black-box-1.jpg

The tail part was recovered separate from the rest of the airplane. Now there could be multiple theories for how the tail might have separated from the aircraft. However, the wreckage captured in the image directly reflects what the patent describes as a worst case scenario.

Now read this.

Exhibit D:


The Airworthiness Directive issued by FAA indicates the regulator’s acceptance of a finding that under certain conditions the allowable load limits on the vertical tail plane can be reached and possibly exceeded. The directive, as specified by the regulator, is valid for all Airbus model A318, A319, A320 and A321 series airplanes. The directive also mentions that the directive is valid from Dec, 29, 2015, indicating that the finding and directive have happened in the recent past. 

Such findings and directives going out so recently indicates that the A318, A319, A320, A321 series airplanes have so far been flying in a state of vulnerability and they have been lucky to escape such accidents simply because of the low probability of such failures. 

So the aircraft can fail under certain conditions. This is something that is always thrown out of the ‘Consideration Box’ used for any air accident investigation. The ideal case scenario of all-aircraft-are-safe is being thrust into our minds through carefully planned press releases and cover-up activities….All after hundreds of human beings went down into the ocean along with the aircraft.

Sadly the story doesn’t end here.

Exhibit E: 


EASA had issued a Proposal for an Airworthiness Directive dated 23rd July, 2014, indicating the need for a correction, failing which the aircraft will stand vulnerable to lose its tail fin during during flying conditions. The image above indicates that this directive was deemed applicable for a wide range of Airbus aircraft including Airbus A320-216, the one that went down.

The proposal also says Airbus has developed modifications within the Flight Augmentation Computer [FAC] to activate a conditional aural warning within the Flight Warning Computer [FWC] to prevent pilot-induced rudder doublets. 

So the European regulator was aware of such a ‘condition of vulnerability’ that Airbus aircraft were under and proposed an Airworthiness Directive [AD]. Irrespective of whether the AD was implemented or not, the fact that Airbus aircraft had vulnerabilities including that of losing the tail-fin during specific flight conditions. As I have always pointed out, the probability of occurrence of any event should have no bearing on the risk perception of the same. Potential impact, in this case is, loss of aircraft and therefore it should have higher priority. For some reason, frequency and probability of occurrence is being used as a key criteria for prioritising any risk-mitigation effort.

Further research back into the past reveals this:

Exhibit F: 


‘Safety First,’ The Airbus Safety Magazine dated January, 2005 featured an article on the need for enhanced pre-flight checks involving risk conditions, with one of them being the failure of the Rudder Travel Limiter Unit [RTLU]. The article, as you can see the image above, classifies it as an ‘event of undue rudder travel limitation.’

2005 is long back and even then, there had been vulnerabilities with respect to the RTLU in Airbus aircraft. This indicates that Airbus aircraft, like any other aircraft has always stood vulnerable to abnormal flight conditions, including those that concerned the RTLU, the system which failed during the QZ8501 accident.

Conclusion

Based on the oddities and interpretations I derive from the observation of the exhibits presented above, this is what I think happened with QZ8501.

The aircraft, like any other had remained vulnerable to specific abnormal flight conditions and the supplier’s effort to mitigate this risk [concerned with the RTLU] resulted in restricting the pilot’s capacity to take control of the aircraft. 

What was deemed as too-much-freedom for error resulted in a change that took too-much-of-necessary-capacity from the flight crew during those specific abnormal flight conditions. 

So when the aircraft went into what was deemed a ‘very-low-probability’ scenario, it deviated away from its dedicated flight-line and it had to be recovered. The flight crew had responded as per procedure three times to recover the aircraft but realised that the risk-mitigation change was not allowing them to do the same. The 4th time, the flight crew had no other choice but to try to disconnect the controls from the flight computer that was implementing the ‘pilot-restricting’ control criteria. Unfortunately, they couldn’t achieve the recovery in time and the aircraft went down with the crew and passengers.

While the nature of the abnormal flight conditions is still kept out of our minds through ‘official’ statements comprehensively covering obscurity and generality, we can recall what the patent describes as a possible abnormal flight condition: engine failure. This is why I wanted to know if the engine part of the wreckage was recovered and if yes, the details of the engine wreckage inspection. 

Summing up, many events must have occurred in a certain unfortunate sequence that led to system failure and the eventual loss of the aircraft QZ8501. We may never come face-to-face with the truth since the truth will stand in the way of a multi-billion dollar market that hangs on the ‘perception of reliability’ the aircraft brands thrust into the operators’ minds. However, we can be sure that solder joint failures leading to electrical discontinuity don’t occur out of the blue just like that. Also pilots are not fools to try to disconnect the flight computer unless the situation demands such an effort. 

When a report says, someone lost their life because of a knife entering their back and that the victim had by some means consciously maintained proximity to a sharp knife during the event, it is absolutely obvious that someone might have stabbed the victim. Just because the report doesn’t use the word stab doesn’t mean the victim absolutely walked into a knife protruding out of something uncertain [in this case the hands of the assailant]. Just my thought.


Regards,


Wednesday, July 1, 2015

Iran Nuclear Deal: Potential Impact on Oil, Aviation & Defense Markets of The Middle East

Hello World,

Image Source: http://www.pbs.org/newshour/rundown/whats-stake-iran-nuclear-talks/


The Middle-East is a fast growing market for multiple industries, with oil, construction, aerospace and defense being the prominent ones. I am trying to get a big picture view of how each of these markets interact with each other and form an interconnected system which is dynamically changing right now. Here are my views on different trends and my interpretation of how activity in one will impact the activity in the other. My focus is especially on the Middle-Eastern aerospace, defense and oil markets and how the Iran Nuclear Deal, should it turn out as expected, will influence them.


Fight for Market Share

OPEC countries want to keep their supply high to compete against western shale-oil and the result will include reduced oil prices. Irrespective of what it is against, the increase in oil supply is happening and is not going to go away soon. As a deterrent to this, ISIS has taken over key oil-supply chains and the Middle-Eastern Administrations need international military support to recover these 'Lost-Oil-Markets.' Getting back the 'Lost Oil markets' from rebel/terrorist groups will add value to the Middle-Eastern oil industry.

Given that this market is already pushing ahead with what may be an 'unrestricted supply' the annexation of lost markets will only pump in more oil into the market, eventually reducing the price of crude oil globally. While more oil can help the Middle-Eastern market gain more market share, the global oil revenues will significantly drop which in turn will impact the spending plans that heavily rely on oil revenues. Although we can't expect that spending to vanish, they will be significantly delayed due to this trend.

Lost Oil markets can only be retrieved through carefully coordinated military operations in those regions which are now under the control of ISIS and other rebel/terrorist groups. The Middle-Eastern defense forces have been modernizing themselves but they are still dependent on western forces for military support [equipment, training and operations]. Now, Western Administrations [NATO countries] don't have the money to spend on elaborate international operations. Even if they did, their help to the Middle-East will indirectly hurt western shale-oil/natural gas industry. Reducing oil prices will impact the Russian military modernization and if this is something desirable to the west, maybe they will let the oil prices continue to fall down. The question is: Will the West think so and if yes will it let the trend take its course?

Secluded Middle-Eastern Commercial Aviation Market [Iran]

On a different angle, US had opened the gates for GE/Boeing to sell commercial aviation hardware to Iran. While this was looking to create a US-controlled [potentially Pro-Boeing] aviation supply to Iran, Al-Naser airlines bought Airbus aircraft [8 A340 and 1 A320] and transferred them to the blacklisted major Iranian airline [Mahan Air]. This means that Airbus has reached the key Middle-Eastern customer faster than Boeing. Iran's commercial aviation industry is expected to take up 400 commercial aircraft, moving forward and this indicates the possibility of a commercial aviation race, should the sanctions be relaxed.

Interestingly, Iran is a member of OPEC countries looking to capture more market share in the oil industry. So, if my crazy view is right to any extent, relaxing sanctions on Iran can get Iran administration's support in restricting oil-supply to get the oil prices rise again. Even if this is not the case, at least the western aviation suppliers will have a new market to sell to. Either ways, the west has more to gain from relaxing sanctions on Iran. The Iran Nuclear Deal is a key instrument for potential opportunities that can lead up to relaxing western sanctions on Iran. The question is: Will the sanctions be relaxed?

The Other Side of Iran Nuclear Deal

From another angle, Israel is concerned with US-driven Iran Nuclear Deal terms. The cause for the concern is the perception of the deal that indicates the possibility of Iran eventually developing a nuclear warhead right after the timeline as agreed over the deal. If this perception were to grow into any other form of concern over Iran's future 'nuclear' capabilities, the Middle-Eastern defense spending will continue to grow [its already growing fast].

Israel has however spent a lot of money on military operations and is potentially looking to sell IMI for cash that can support its defense aspirations. The projects under hold include US DoD FMS programs. Supporting Iran with relaxed sanctions can help west make another friend among OPEC countries but the Nuclear Deal will potentially hurt its friendly relations with Israel, a big-ticket FMS customer for The US. The loss however won't be as big as the corresponding benefit from the growth of the Middle-Eastern defense spending fueled by the concern over the [successful execution of] Iran Nuclear Deal.

The Iran Nuclear Deal, will therefore open up Iran to international [especially western] suppliers and also secure Iran administration's obligation to support any western efforts to influence OPEC countries from continuing to increase oil output. The question is: Will the Iran Nuclear Deal cover such obligations?

What's the Big Picture?

Not supporting Middle-East with turn-key military operations will help curb oil-pressure on western shale-oil and also positively influence the Middle-Eastern defense spending. It is about time the Middle-Eastern administrations developed their indigenous capabilities to sustain any regime stabilization supported by western military help. No point in western forces conducting operations when right after their pull-out, things start getting back to where it was. 

On the other hand, securing Iran from sanctions will create opportunities with Iran in the commercial aviation domain, much to the displeasure of its neighbors. So, in the end, Oil+Commercial will stand taller than Defense opportunities in the Middle East. 

For Iran's commercial aviation opportunities, Airbus is looking to be a potential winner by reaching the customer even during the times of sanctions, but the competition is very close. 

French delegation representing big businesses in France had visited Iran as of Jan, 2014 to discuss potential business opportunities as the French administration foresaw a potential deal that will relax the sanctions on Iran allowing western suppliers to sell to Iran. Here is a news report:

http://www.reuters.com/article/2014/01/15/us-france-iran-idUSBREA0E1IZ20140115

Summing up, the Big Picture view is that the Iran Nuclear Deal will create:

• Successful Commercial Aviation Opportunities in Iran
• Extended Defense Opportunities in the rest of the Middle-East
• Possible influence into the OPEC-driven oil-market

The Big Picture questions are:

• What does the West consider the most important?
• How is the Middle-East planning to prepare itself for any turn of events?


PostedToday.Org Features CrazyMotts Blog!!!!!

Thanks to PostedToday.Org for featuring this blog post on their breaking news - international headlines segment.

Image Source: http://posted-today.org/2015-07-10/


Here are the twitter responses for this view from Experts:

Thanks to the experts for taking time to read my blog post and sharing their insights with me via twitter!!!!

Nathalie Goulet, Attorney, Senator [Orne], Senate of France, Member of Committee on Foreign Affairs, Defence and Armed Forces, Member of Union of Democrats and Independents-UC



Hossein Dalirian, Reporter, Tasnim News Agency:


Hussein Al Shimmary, Independent Journalist and Political Analyst:

Alborz Habibi, Journalist, Contributor to YourMiddleEast:

Saeed Khatibzadeh, Resident Representative, Institute of Political and International Studies, Iranian Embassy, Berlin:

Mostafa Dehghan, Freelance Journalist based at Tehran:

Dirk Hanke, Finance/Risk Analyst:

John-Michael Kibrick, News Editor, ynetnews.com:
Feel free to read John's opinion on the Iran Nuclear Deal at ynetnews.com


Helen Robertson, Oil Market Editor, OPIS:

David Shorr, Foreign Policy/International Affairs Expert, Consulting Program Officer, William & Flora Hewlett Foundation:

Sam Cutler, Editor-in-Chief @ Sanction Law, Policy Advisor @Ferrari & Associates:

Ali Ghezelbash, Co-Founder @ European Iran Research Group:

Reza Akhlaghi, Editor and Senior Blogger, Foreign Policy Association Blogs:

Siavash Fallahpour, Journalist based at Tehran [Covers  Middle East & Arab Affairs]:

Dr. Mohammad Gharebag, Staff Writer @ KYODO NEWS:


Karim Emile Bitar, Senior Research Fellow, The French Institute of International and Strategic Affairs [IRIS]:
I followed up with this question for Karim:

Do you think P5+1 countries will compete for biz-opportunities and take different stands on sanction-relief clauses for Iran?

Bradley Harris, Lobbyist @ Friends Committee on National Legislation [FCNL]:

Joshua Noonan, Presidential Management Fellow, US Dept. of Housing and Urban Development, Post-Soviet Analyst and Expert:

Raquel Redondo, Freelance Journalist [Covering Iran Nuclear Talks since 2012]:

Roberto Neccia, Iran Analyst, Diplomat @ Italian Ministry of Foreign Affairs:

Update as of 29th Oct, 2015:

As indicated above, Iran has announced its intent to buy aircraft from Airbus and Boeing. Here are the post deal news reports:

Iran plans to buy 80-90 Boeing, Airbus planes a year, post sanctions


http://www.reuters.com/article/2015/08/02/us-iran-planes-idUSKCN0Q705W20150802

Iran plans Airbus, Boeing purchases under finance deals

http://news.yahoo.com/iran-plans-airbus-boeing-purchases-under-finance-deals-130647427.html


Five New Airbus Airplanes to Join Iran's Civil Fleet


http://www.aviationpros.com/news/12113892/five-new-airbus-airplanes-to-join-irans-civil-fleet


American Coalition Against Iran

http://www.unitedagainstnucleariran.com/company/airbus-group



http://www.uskowioniran.com/2015/10/iran-close-to-deal-with-airbus.html


Update as of 26th Jan, 2016:

Iran marks comeback with talks to buy 160 European planes [includes 127 Airbus Jets]


http://www.reuters.com/article/us-iran-aviation-idUSKCN0V2098


I see that things are moving forward as expected. Good times for Iran. Hope the regional peace grows with this sanction removal and subsequent economic exchanges.

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Best regards,


Tuesday, September 10, 2013

GNSS IN COMMERCIAL AVIATION: IMPACTS, OPPORTUNITIES AND CHALLENGES



Hello World,

With the increasing demand for air-travel, the commercial aviation industry has been experiencing rapid growth all over the world, with increasing number of air routes and aircraft, owing to the entry of airlines and expansion of existing airlines. This rapid growth has simultaneously witnessed various challenges including financial, regulatory and operational challenges to name a few. The operational challenges seem more significant from the growth standpoint as these challenges obstruct airlines and regulatory bodies from utilizing the available opportunities to the full. With the increase in the number of aircraft, airspace management has become more challenging than it was before. Safety and accessibility are the main elements of the operational challenge that airlines, airports and regulatory bodies face. With the advancement of technology, there have been simultaneous innovations into instrument-guided airspace management procedures. These technology implementations often take the form of Augmentation Systems, with their infrastructure being ground based for the most part. The space programs have contributed multiple constellations of navigation satellites, which have added to the efficiency and accuracy of these augmentation systems that are used to guide aircraft. This inclusion of the space segment into the otherwise ground-based augmentation systems has made the concept of aircraft guidance and tracking, a more versatile and reliable practice that is being used to manage airspace around the world. It would be beneficial at this point to look at the possible applications of satellites i.e., Global Navigation Satellites Systems (GNSS) in the commercial aviation industry, with a specialized interest into business opportunities that may emerge as the result of this technological advancement. This research, in its own limits, attempts to look into the aspects of growth of commercial aviation, the resultant airspace management requirements and the subsequent opportunities that may involve the application of GNSS in commercial aviation. Click here to download the pdf version of this post.

Objectives

The primary objective of this post would be to identify the future trends of commercial aviation that may demand the implementation of GNSS-based augmentation systems. The secondary objective would be to identify possible aspects of GNSS-based systems that may satisfy the future airspace management requirements of the commercial aviation. The discussion objective would be to interpret the relation between the primary data and secondary data and arrive at a brief description of possible impacts, opportunities and challenges to be faced while attempting to implement GNSS-based systems in commercial aviation.

Methodology

This research would tend to be interpretative in nature and therefore it shall require initial inputs from individuals with professional experience in the aviation sector regarding the impact of implementing GNSS in commercial aviation and growth of commercial aviation in general. These inputs would serve as the primary data, based on which internet research shall be carried out to obtain published research work from the private and government sectors that may serve as secondary data.

The data collected shall be analyzed to capture important aspects of commercial aviation that may require the application of GNSS and the subsequent impact of GNSS on it. Interpretations shall be made based on the facts obtained from the primary and secondary data and it shall be used in further discussion.
Primary data was collected through telephone interviews. Secondary data was collected from various online resources based on the interpretations of primary data.

Primary Data

Interviews

Interview-I:

Interviewee: Certified Flight Dispatcher (Past)
Trained on: Boeing 737 (Location: UAE)
Interview Summary:
He briefly explained how flight operations are managed by flight dispatchers in coordination with various departments and air-traffic controller. He stressed the importance of scheduling and filing of flight plan and the important aspects of the flight plan that directly impact the airline operations. When asked regarding GNSS applications in commercial aviation, he responded with positive comments for GNSS applications, mentioning the systemization of the process and how drafting flight plans would be simplified owing to standardized cruise and approach routes that are implemented as a result of implementing GNSS. He also mentioned about the segmented airspace controlled by each airport and how the segmentation impacts the airport operations.

Interview-II:

Interviewee: Aviation Business Analyst
Experienced in: Forecasting (Aircraft Manufacturing & Sales)
Interview Summary:
He briefly explained about the trend in aircraft sales over the past few years where the delivery backlogs have steadily increased, indicating the expected addition of aircrafts to various fleets in the coming years. He mentioned that, as a precautionary measure, buyers have chosen their delivery times much further into the future, expecting the economic climate to recover before they receive their ordered aircrafts. He also mentioned that, in the coming years, more aircrafts are expected to be added to the current fleets, influencing a denser air traffic pattern. While talking about air traffic in commercial aviation, he mentioned that in the past few years there have been many mergers among airlines resulting in increased fleet size. He mentioned that if the airlines which bought the aircrafts used them to increase number of flights in existing routes, the corresponding airports would begin to face denser flight traffic.

Secondary Data

Published Research Work

Based on the interpretations of the primary data collected through interviews, the subsequent internet research was done and published research work from the academic, government and industrial sectors that are available in the public domain were downloaded. The documents were read and specific information and ideas pertaining to the topic at hand and those corroborating the ideas captured in the interviews were picked, studied and the subsequent interpretation of the ideas were used as the basis for the discussion presented below.

Growth in Commercial Aviation

As per the estimates of Global Traffic Forecast initiated by Airports Council International for the period of 2006-2025, the world passenger volumes is expected to increase by 4% annually and the freight volume is expected to increase with a growth rate of 5.4%. These estimates indicate the need for more air travel which may be satisfied by increase in the number of flights and addition of aircrafts. The commercial aviation sector, that tends to meet the major portion of the demands of the increasing passenger and freight traffic, is set to grow over time, making airports busy and airspace management more complicated. This increase in aircraft movement would result in the increase in the need for supporting infrastructure in the forms of newer airports, additional air routes and improved air traffic control systems. 

The Global Market Forecast for the period 2012-2031, done by Airbus, indicates that the air traffic between advanced and emerging air transport markets is expected to increase at an average annual rate of 5.1%. The forecast also indicates that the number of passenger and freight aircraft fleets, by 2013, is expected to have increased by 109% and 82% respectively.

This growing number of aircrafts would require an increased availability of aviation infrastructure, mainly airports and air traffic control systems. The primary demand would therefore be for availability of space on land and in air, to meet the operational demands of safety and accessibility, which may translate into more and larger airports with more efficient air space management procedures. The improvement if airspace management procedures would help make use of the available infrastructure to the full, by contributing to safety and accessibility.

This evolution of airspace management has so far been predominantly dependent on aircraft/ground based augmentation systems and with the implementation of GNSS, the satellite-based augmentation systems have emerged with increased capabilities and efficiencies. The future of better airspace management would however require a combined implementation of ground-based and satellite-based augmentation systems, facilitating the evolution of more versatile and adaptive augmentation systems that may include ground and space segments working together to achieve the objectives of efficient airspace management. The cost constraints of implementing GNSS-based guidance system may be considerably lowered by using the available ground-based augmentation systems. It however is an obvious requirement that the ground-bases augmentation system be compatible with GNSS and related systems.

Need for Improved Airspace Management

With more aircrafts and more flights, the air traffic gets denser requiring airports to implement GNSS-based airspace management systems and procedures in order to ensure aircraft safety and airport accessibility. Making airports accessible to more aircrafts means, more air traffic near airports which in turn indicates increased risk of accidents. As per the Statistical Summary of Commercial Jet Airplane Accidents (1959-2008) released by Boeing indicate that 36% of the accidents take place during the final approach/landing phase and 20% of accidents take place during take-off/initial climb phase of flight. Fig.1 given below indicates various phases of flight and the percentage of accidents/fatalities that occurred during 1959-2008. 

Fig 1. Accidents/Fatalities by Phase of Flight
(Source: Statistical Summary of Commercial Jet Airplane Accidents, 1959 - 2008, Boeing)

This translates to the fact that aircrafts are more vulnerable to accidents in the controlled airspace around the airports than anywhere else. Therefore, the airspace management systems and procedures need to address the need for increased airport accessibility and risk of accidents. 

The major airspace management requirements to be satisfied are:
·   -      Optimization of aircraft holding areas in air
·   -      Avoiding collision
·   -     Increased airport accessibility 

These major requirements can be met with the following elements of airspace management (including but not limited to):
·  -       Improved instrument flight procedures
·  -       Predictable/repeatable flight trajectories
·  -       Closely spaced routes
·  -       Implementation of progressive airspace management regulations

The application of GNSS would contribute to the design and implementation of efficient satellite-based augmentation systems and procedures that may include the following aspects:
·  -       Improved flight path monitoring tools
·  -      Increased systemization of navigational control procedures
·  -     Increased controller productivity
·  -    Increased system adaptability to evolving airspace user requirements
·  -   Increase in controlled airspace capacity

GNSS in Commercial Aviation

There are multiple GNSS in operation and many global and regional navigational satellite systems are expected to be in operation in future. Application of GNSS requires accessibility to the navigational satellite system and corresponding augmentation systems that accommodate the space segments in addition to the ground based augmentation infrastructure. The civil aviation regulations also play an important role in the design and implementation of such GNSS based guidance systems. Fig. 2 given below shows a schematic representation of a typical GNSS based airport guidance system:

Fig 2 Typical GNSS Based Airport Guidance System
(Source: US Patent No. US 6,182,005 B1 dated Jan 30, 2001, Pilley et al)

As described in Fig.2, the GNSS based guidance system would be composed of a framework of ground and space segments, mobilized by systemized detection, processing and display of vehicle positioning data, relying on standardized databases that contain all the necessary data. This also means that such a GNSS-based system would implement a high level of systemization, reducing the chances of human error that may cause anomalies in air traffic management processes.


Impact of GNSS in Commercial Aviation

Satellite-based augmentation systems add to the operational efficiency and accuracy in a multitude of operations including:
·       -   Departure Operations
§  Take-Off
§  Initial Climb
·       -   Arrival Operations
§  Approach
§  Landing
·       -  En-route Operations
·        -  Terminal & Surface Operations
·        -  Collision Detection & Alerting (based on Trajectory Prediction)
This implementation of GNSS-based systems would result in the upgradation of conventional instrument-controlled flight procedures/systems or their subsequent decommissioning, owing to the entry of the more precise satellite-based augmentation systems. The implementation of GNSS-based systems would however be transitional in nature, spread over an extended period of time, owing to the installation requirements in terms of ground-based and on-board equipment and subsequent air-traffic procedural amendments as regulated by the civil aviation authorities of the region. This is one reason why any ground-based augmentation system needs to be designed so as to allow future GNSS compatibility.
From the operational standpoint, air traffic controllers and pilots would have enhanced navigational data with both ground-based and on-board graphic displays apart from the simplification of instrument-controlled flight procedures which may reduce pilot fatigue and enhance operational easiness. The airports would be able to handle more air traffic efficiently and the operators would have reduced burden of safety with respect to flight operations. There will be an element of “situational awareness” among the air traffic controllers and pilots enabling easy identification of conflict scenarios.

With the implementation of standardized airspace management procedures, airports in their own region would have enhanced interoperability, simplifying operations in the particular region. There will be fewer major operational discrepancies and corresponding transition methods in place for uninterrupted flight services between airports from different regions (with contradicting aviation regulations). 

Europe and the US has so far been the major user of GNSS-based guidance systems in commercial aviation. The Russian, Chinese navigational satellite systems also provide similar navigational opportunities to their respective commercial aviation sectors. The availability of an indigenously developed navigational satellite system would considerable reduce the cost of implementing such systems in the commercial aviation sectors.
The concept of GNSS-based aircraft/airport guidance is very subjective and therefore may vary in terms of applied methods and processes from place to place, owing to the geographic, regulatory, air-traffic and operational constraints. The GNSS-based guidance systems, though following an overall system design pattern, would tend to vary from region to region in terms of their size, operational functions and range. Therefore implementing GNSS-based guidance system for developing air transport markets may be different as compared to that for an already existing air transport market.

Opportunities To Be Explored

 

Navigation Infrastructure:

From the emerging navigational technologies perspective, the primary requirement for design and implementation of a GNSS-based guidance system would be the assessment of the navigational needs and existing navigational infrastructure. The system in its course of design and implementation would require continuous monitoring and assessment. Therefore, opportunities for Navigational Infrastructure Assessment would be an important domain that would require players to meet the demand for assessment of navigational needs and infrastructure in the implementation of GNSS-based guidance systems. These opportunities would create requirements of GNSS-compatible navigational equipment and implementation/maintenance services in the short and long-term. Depending on regional civil aviation regulations, the GNSS-compatible avionics may need to match specific regulatory and user requirements. The design and development of such avionics is another field of opportunity that would be a result of implementing GNSS-based systems in commercial aviation.

Navigation Specification:

Development and implementation of improved instrument-controlled flight procedures is another domain of importance which requires multiple players to work in collaboration with regional civil aviation regulatory bodies. For the implementation of any satellite-guided system, there would be corresponding changes to conventional air traffic management practices. Private sector businesses that specialize in technology research and consulting would have ample opportunities to work with airport administrations to implement their choice of GNSS-based guidance systems and procedures. There would be demand for airspace planning and trajectory design that would need to be addressed.

Testing, Training & Certification

With the implementation of GNSS-based augmentation systems, airport operators and airline operators would be required to install necessary navigational equipment, on ground and on board. The testing, analysis and certification of such instruments so as to match the regulatory requirements of the region would be an operational burden that operators would be willing to outsource to private players. Also training the process owners including the controllers and pilots with the new systems and their functionality would be an operational exercise that operators would be required to do which again can be outsourced to private organizations that specialize in imparting such technology training programs and related services.

Challenges for GNSS Applications in Commercial Aviation

The application of GNSS in commercial aviation, in spite of its technological superiority and adaptability, would face the following major challenges (including but not limited to):

Cost:

Additional installation of GNSS-compatible equipment in the ground stations and aircrafts and their subsequent certification before use imposes a substantial cost on the airline operators and airport authorities. The civil aviation regulatory bodies of each region need to restructure their regulations so as to accommodate implementation of such systems so that airline operators are motivated by a substantial benefit in exchange for volunteering to the transition.

Back-Up:

A progressive decommissioning of augmentation systems that are replaced by GNSS-based systems would impose the risk of not having a viable back-up as a deterrent to the technological transition. Therefore the basic infrastructure for the existing ground-based augmentation systems need to be kept alive and synchronized with the satellite-based augmentation system so as to serve as a back-up in case of a system failure in the event of deliberate jamming or solar flares. This would impose a requirement for ground-based augmentation system infrastructure to be GNSS-compatible so as to allow future transition.

Time:

Flight trials analysis involving GNSS-based approaches conducted through a collaborated effort of Imperial College of London and University of Leeds, indicates that a large portion of the pilots were confused with the system installation status and the most safety relevant issue was pilot confusion over range information displayed that complicated the calculation of vertical descent profile. This is an indicator that an implementation of a newer navigational system and corresponding procedures would require a formal training program so that the process owners (pilots and controllers) get oriented to the new system features and improved procedural formalities. Any abnormalities identified during the training period would require system/sub-system level changes. There will be a significant time and resource cost to be met while attempting to train the process owners with newer technologies and optimizing the installed infrastructure/equipment as per the feedback received during the operational testing. Any time delay in the implementation to the effective-in-operation stage would mean that the investment would take longer time to respond with a return, which may impose financial constraints that may be demotivating to the investors.

Conclusion

The application of GNSS in commercial aviation, in terms of technology is a valuable advancement that caters to a diverse set of demands that may arise due to the expansion of the commercial aviation market. Although developed air travel markets have implemented GNSS in their commercial aviation sectors, the implementation has so far required intensive regulatory, infrastructural and technological transformations and is bound to evolve further with standardized regional airspace management concepts. The developing air travel markets would have an additional burden of infrastructural costs as they are yet to become entirely compatible to GNSS-based systems. With civil aviation authorities coming forward with appropriate regulatory changes combined with a collaborated effort from airport/airline operators and technology partners, application of GNSS in commercial aviation would turn out to be beneficial to all the entities constituting commercial aviation. GNSS would increase the safety of aircrafts, especially while operating the controlled airspace of an airport, adding to the operational ease and accessibility to airports, positively impacting the fast growing commercial aviation sector. There is a cost constraint that may hinder the smooth transition into GNSS-based technology and a financial analysis of such implementation, on a case-by-case basis, elaborating the cost versus benefit aspects of implementing GNSS in aircraft/airport guidance would help operators in deciding on transitioning to the new technologies.

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References

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