Re: [SystemSafety] Boeing 787 position flaw

From: Peter Bernard Ladkin < >
Date: Tue, 5 Jan 2016 16:25:44 +0100


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I have seen a presentation which includes some words on the subject, from April 2015.

The issue was first noted by Air Services Australia on October 29, 2014. By April 2015, it had occurred overall to 15 flights on 7 different aircraft. In all cases, the flight crew did not report and problem and the aircraft was always on the "proper" track.

Root cause was determined to be an integration issue between the Integrated Surveillance System (ISS) and the GPS position data, received via the Remote Data Concentrator (RDC). When GPS latitude & longitude data are split across multiple network (AFDX) data packets, the ADS-B position extrapolator will not update its position with fresh, valid GPS data. ADS-B position will then deviate from the point at which latitude & longitude were in the same AFDX packet.

The data flow is that GPS signals are received and processed by the Honeywell Integrated Navigation Receivers (INRs). The info is sent via ARINC 429 bus to the Remote Data Concentrators (RDC) which pass it on via the Rockwell Collins Common Data Network (CDN, a commercial standard which implements ARINC 664 and is similar to Airbus's AFDX) to the Rockwell Collins ISS Processing Units, whence it goes to the TCASE/ATC antennae. For a little more background, http://www.intelligent-aerospace.com/articles/2011/06/boeing-787-avionics.html might be helpful.

Probability of occurrence of the phenomenon and its duration are said to have varied

As of August 2015, Boeing 787 aircraft are delivered with a Rockwell Collins ISS-2100 (Integrated Surveillance System), which includes ATC Transponder, ADS-B Out, TCAS/ACAS, Terrain Awareness, and Weather Radar. Version 2 of ADS-B Out is an onboard-loadable software update. It is DO-260B and it fixes the problem (according to design review and integrated testing in the lab) and is said (in April 2015) to have been available in August 2015.

PBL Prof. Peter Bernard Ladkin, Faculty of Technology, University of Bielefeld, 33594 Bielefeld, Germany Je suis Charlie
Tel+msg +49 (0)521 880 7319 www.rvs.uni-bielefeld.de

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