787 navigation-location issue
 

Almost ' lost in space '

https://www.flightglobal.com/news/ar...n-data-419916/


from flight global

• 10 DECEMBER, 2015
• BY: STEPHEN TRIMBLE
• WASHINGTON DC

Quote:

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Most of the Boeing 787s delivered to date contain a software defect that, in at least five identified aircraft, have erroneously reported their location to controllers, prompting two air traffic management agencies to put the Dreamliner on a “blacklist” for certain services.

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Quote:

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Although it denies the software defect creates a safety hazard, Boeing says a service bulletin with instructions for operators to correct the position reporting error will be released “imminently”.
The retrofits are expected to be installed across the fleet through 2016, but Boeing has no control over if or when an operator chooses to implement a voluntary service bulletin, the company says. New 787s delivered from Boeing’s assembly lines are already equipped with software that corrects the original defect.
The issue came to light last December at an ICAO working group focused on automatic dependent surveillance-broadcast (ADS-B) transponders.

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Well, he would say that, wouldn't he?

The answer is in the quote : "Boeing says "
Communication strategy and an quote from someone who does not know how ADS works and is certified, of who has been told but choose to say this to take the heat away.

It is a real safety issue , hence the reaction of the various ATC service providers.

If this really was/is a safety concern I am sure the FAA would mandate the SB and make it an AD therefore making compliance mandatory.

As far as I know the US does not currently use ADS-B as sole means of surveillance with 5 NM lateral separation , like Australia and Canada do.

That really is not the point. The ADS-B report is a position report and will be used as that; it must not be wrong. In many multisensor systems and mosaiced systems the controller could be unaware that the track is being supported solely by ADS-B. ANSPs who mandate ADS-B operation in their airspace should ban those aircraft with defective ADS from operating in their airspace. That might hasten action by dilatory operators.

It's going to be EXTREMELY relevant for RLat operations on the NAT system shortly....

Actually, right now.

RLatSM trial is already underway.

As far as I am aware even US registered B787s fly out with the good ole USA.

As the Flightglobal article states, Nav Canada did blacklist 71 airframes (representing 12 operators) which meant that when in Canadian airspace, though not banned from operating, they would have procedural separation standards applied.

Great in theory, but no way would I accept an aircraft I couldn't see into a busy sector. It's just asking for a foxtrot uniform.

I assume these affected 787s are currently fl340 or below or on random routes in NAT airspace atm to comply with current FANS restrictions?

If ATC are seeing the wrong position, then how on earth can Boeing say it isn't a safety issue?!!

The NAT is using ADS-C not ADS-B and if the Flightglobal description of the problem is correct then the issue probably doesn't affect that reporting.

It would be a problem for any ANSP using ADS-B as the sole means of surveillance in busy airspace but as others have said few do. It is an example of the sort of issue that makes some believe you need to support ADS-B with other techniques such as multilateration if you want ADS-B to achieve separation standards similar to those obtained with radar.

It won't spontaneously combust ?

Unless it's one of two aircraft occupying the same bit of sky at the same time, because ATC think it's 30 miles away from where it actually is ...

Some engineering questions:

* why was a system allowed to send only parts of critical data streams?
* why was the receiving system allowed to use such a crass dead-reckoning computation to guess where it is?
* how did any of this get certified?

It also raises serious questions for aircraft utilizing ADS-B IN for traffic awareness/de-confliction.

ADSB is safe
ADSB is safe
ADSB is safe


You will see ADSB-IN used as soon as there is encryption in the broadcast, (ie never)

Now one can understand why ADSB mandate is now 2020 in the US, and will likley slip even further.

As for AUS, pioneers get slaughtered and settlers prosper.

Just to put things in perspective.

There are very many aircraft types out there that do not meet the requirements for using ADS-B for ATC separation. Therefore in regions where ADS-B separation is available they must be segregated, separated procedurally and may as a result get an inferior service.

The only issue here is that the 787 as a new aircraft should be meeting the standards and apparently is not. If the aircraft was falsely reporting a high integrity ADS-B then this would be a significant safety issue. But now the problem is identified and the type is blacklisted the 787 is simply relegated, for the time being, to the level of all those other types that do not meet the standard.

However this is an ADS-B issue only and does not affect normal radar separation (primary or secondary) in any way.

It's not an "if" - the aircraft in question were falsely reporting a high integrity ADS-B and this was categorised (by Airservices Australia) as a Class C operational risk (though I can't find a definition of that anywhere).

Similarly, the Canadian take on the issue:

"Nav Canada’s permission to provide reduced separation using ADS-B is based on the premise that ADS-B position reports contain integrity values (NIC, NAC, NUC, SIL) that provide assurances for their use by ATC. The position anomalies generated by the B787 ISS are the first of their kind, and appeared to be a critical failure in the system; the provision of data with false integrity.

Nav Canada reviewed the nature of this error source against the assessment process which permitted ADS-B to be used as a surveillance source. This particular scenario of an aircraft continuing to report position with the required integrity values when it is in fact not in that position, was never imagined, nor covered, during any of Nav Canada’s hazard identification and risk analysis work."

Luffa totally agree and even though I am from EASA land am sure they would as in this day of blame claim there is no way that they would leave themselves open to this not withstanding the FAA certification division have my confidence in mandating as required.

Dave,

I believe the ASA was referencing Class C airspace operations risk

According to the ICAO document it's a Class C risk as assessed using Airservices Australia's own risk management framework. You are unlikely to find that published anywhere but according to the ICAO document it has four levels A, B, C and D. It states that A is unacceptable and D is acceptable but we need to guess about B and C. We can assume that C is tolerable as they weren't required to use the mitigation they had previously identified and we know the Chief ATCO was required to agree so C appears to be a tolerable risk if signed off at a senior level.

It is interesting that one ANSP identified a Class C risk and the other states that they never imagined that possibility in their hazard analysis. I can see that different safety management systems might give different interpretations of the risk but to not even consider the possibility suggests shortcomings in the hazard analysis process. I hope that is a one off and their hazard analysis is a bit more thorough for other operational risks.

WTF Am I Missing?
 

I've been following this issue and I guess I'm still missing one critical part. Reports and Boeing information suggest that only SOME 787s are affected. To my eye that suggests that they have a fix and have already applied it to SOME airplanes. While it could be as simple as a revised software load, it might also be a hard-coded (hardware) modification that is required. Either way, it appears that they know what needs to be done. The next leap has to be, So Why Has it Not Already Been Applied to the Entire Fleet? This is a new fleet, so the fix is Boeing's responsibility, either last week or next week. Again, What Am I Missing? Is this not already FAR past the need for a formal AD?

"Nav Canada first detected a problem on 1 July 2014 when controllers noticed a 787 appearing to deviate up to 38nm" July 2014?!!

"Boeing has no control over if or when an operator chooses to implement a voluntary service bulletin, the company says."

How hard could it be to get in touch with the owner of every 787 and make sure every aircraft gets the upgrade? It would seem to be in the best interest of Boeing and the 787 owners.

When my partnership added ADS-B in & out to our PA-28-181 we were not suppose to use it for IFR until it passed a quality check from the FAA.

To their credit, the FAA makes it easy to accomplish the check just by sending an email to them.

The controllers here in Central Texas do use ADS-B for aircraft separation, even when the aircraft is out of radar coverage.

Hi JimNtexas, hope your ADS-B does not have the same fault, or you might be making that jump in hyperspace... http://www.pprune.org/images/icons/mpangel.gif