|Wireless GroundLink® Quick Access Recorder FAQs
FAQs about Teledyne Controls' Wireless GroundLink® System
A. What is Teledyne's Wireless GroundLink® System (WGLS)?
D. How does the Wireless GroundLink system work?
A.1. Teledyne's Wireless GroundLink® system is an automated solution that securely transfers recorded QAR or DAR flight data from the aircraft over public GSM cellular wireless networks and the Internet to an airline's flight safety or engineering department.
A.2. The Wireless GroundLink system provides a quickly implementable wireless solution for Flight Safety FOQA/FDM departments seeking the ability to review in-flight data in a timely manner. If an airline's objective is 100% recovery and analysis of aircraft data for all flights flown, this system is the ideal solution.
A.3. The system does not require the airline to invest in infrastructure since it uses low-cost public GSM cellular networks already in existence at every airport today.
B. What is the difference between QAR and DAR data?
Typically, QAR data output from a data acquisition system is an exact copy of the flight recorder data and is not programmable. In comparison, DAR data output is programmable by the airline through making loadable software and/or database changes without any requirements or re-certification of the acquisition system. Furthermore, the DAR output produces larger volumes of data for ground analysis.
C. What is the difference between Wireless GroundLink (WGL), Wireless QAR (WQAR), WGL-DAR, WGL-QAR? Are they different products?
C.1. These are different names for the same product, but they record different data depending on the user's objectives:
C.1.1. WGL is the basic Quick Access Recorder device that can also be customized to record specific data from various onboard recorders which determines the extension given at the end of the product name. An aircraft may have QAR or DAR provisions (or both for Airbus aircraft) and either one of the provisions can be modified to support installation of the WGL system.
C.1.2. When the system is installed on an aircraft for the purpose of recording Digital ACMS Recorder (DAR) data from the Aircraft Condition Monitoring System (ACMS) the unit is named WGL-DAR.
C.1.3. When the system is installed on an aircraft for the purpose of recording a copy of flight data recorder data (also known as Quick Access Recorder or QAR data) the unit is characterized as a WGL-QAR or WQAR.
D.1. Teledyne's WGL uses a different approach for transporting data. Rather than installing dedicated data links between the aircraft and the gate, the Wireless GroundLink system utilizes two highly ubiquitous communication platforms: the public GSM cellular infrastructure, and the Internet.
Data collected during the flight is compressed to reduce transfer time and cost, then it's encrypted for security, and prepared for transmission.
After landing, the WGL unit opens one or more (up to eight) communication channels over the local GSM cellular network. The collected, compressed, and encrypted file is divided into data packets and transmitted over the air.
While the data is in transit over the air from the WGL to the local cell tower, the data packets are encrypted further by the GSM network. Once received at the cell tower the additional GSM encryption that took place over the air is removed.
At the GSM cellular network switching center, the packets are sent through the Internet and routed to their target destination, the airline's operation center or Teledyne's Flight Data Services center.
A VPN tunnel or a dedicated leased line can be optionally utilized between the GSM infrastructure and the airline's operation center.
There, the packets are received by a ground station computer that's running the Wireless Ground Base Station (WGBS) software, where the packets are reassembled, decrypted, decompressed, and verified for data integrity.
D.2. The AirFASE® software, or another analysis tool, receives the complete file in its original format as it was recorded on the aircraft. Automatic reports can be generated and made electronically available for appropriate airline managers to review. In most cases, the reports can be reviewed before the passengers have de-planed the aircraft at the gate.
E. What are the advantages of the Wireless GroundLink approach?
E.1. The Wireless GroundLink system is a low-cost solution that can be implemented immediately to meet airline's data transport requirements. There are no transmitters, receivers, or fiber optic cables that must be installed at airports. The required GSM infrastructure already exists; therefore the Wireless GroundLink solution's capabilities are available immediately, not years from installation.
E.2. The Wireless GroundLink system has an integrated antenna that requires no penetration of the aircraft pressure vessel - the GroundLink antenna effectively transmits to nearby GSM cellular towers through the fuselage.
E.3. Teledyne can provide a comprehensive end-to-end solution that includes the WGL device, data acquisition hardware, installation kits, certification, as well as ground data replay and analysis software.
E.4. Teledyne's Wireless GroundLink's end-to-end connectivity also enables airlines to easily use Teledyne's Flight Data Services.
F. What is the Wireless GroundLink system's typical data transfer rate?
F.1. Under normal operating conditions, an hour of in-flight recorded data (B737 or A320) will take between 2 and 8 minutes to transfer to the flight operations center depending on how the system is configured.
G. Is the aircraft installation complicated?
G.1. Teledyne's current Wireless GroundLink configuration combines the wireless hardware and software in a Quick Access Recorder (QAR) 4-MCU package. The unit's size meets aircraft compatibly requirements and simply slides into the existing avionics rack location. A small antenna (4-inches long) is located on the front panel of the unit.
G.2. The system is available as an option from Boeing and Airbus on all production aircraft/aircraft in production.
G.3. Teledyne has multiple STC and installation kits available to meet your aircraft retrofit needs. Additionally and on request, Airbus and Boeing provide retrofit installation Service Bulletins (SBs) and install kits for WGL installations.
H. What level of security (e.g. encryption method) does the WQAR offer/provide?
H.1. WEP and WPA and SSID are applicable to 802.11 technologies and not GSM cellular.
H.2. Most, if not all, GSM cellular networks for the Airlink use 128 bit triple DES algorithm for encryption and session authentication. Additionally, SIMs and GTP tunnel provide standard GSM technology security. Additional optional security measures are also available (e.g. private IPs, private APN, VPN tunnel or a leased line between GSM network and the customer).
H.3. In specific regions of the world, customers can verify if their local GSM networks provide additional security provisions (such as in Japan). GSM is considered very secure - so secure that it can be used to certify updates for 802.11 systems which are fundamentally less secure.
H.4. Beyond GSM security, the WQAR and base station have additional security measures to protect flight data by using proprietary encryption originally developed for a military application. The algorithm is symmetric and multi-round, and highly secure as an added security evaluation of Teledyne's algorithm was conducted by an independent expert who did not identify any weakness when compared to the DES algorithm.
H.5. The WQAR units are delivered set to a standard encryption key. The user can also deploy encryption key changes wirelessly to the WQAR units from the base station; however not even one customer has used the extra encryption because the standard security is considered more than adequate. To illustrate further, Lufthansa wanted Teledyne to support their own special encryption but once they reviewed the WQAR and GSM security measures, they decided extra encryption was not necessary after all.
Not a single security breach has been reported since the system was first deployed in 2001.
I. What is the benefit of using two or more SIM cards?
I.1. There are four reasons for using more than one SIM card:
I.1.1. SIMs from different networks and countries can be installed, and the system can routinely download data to the local SIM on its own local network. This allows for low cost data transfer in different countries without routinely using roaming. Please note however that SIMs should be enabled for roaming for test purposes while at Teledyne UK and USA facilities and for on-exception use of the WQAR's Download-on-Demand (DoD) feature, which allows data transfer in under "out-of-network" conditions when roaming outside of the normal operating configuration of the unit. DoD allows operators to send a one-time SMS text message command to the aircraft's WQAR unit to activate immediate data download from almost any airport in the world back to the airline's home base. This function allows timely retrieval of critical flight data, which can alleviate physical inspection of the aircraft and significantly reduce delays related to resolving Aircraft On Ground (AOG) issues.
J. How is a WQAR added to an aircraft?
I.1.2. Using more than one SIM in parallel allows for greater bandwidth and for transfers to occur more rapidly.
I.1.3. Using more than one SIM allows for data transmission costs of the WQAR unit to be minimized or optimized as needed. For example, if a given network has a price plan for $20 per month per SIM for 100MB usage and the next option is $50 for 500MB, and assume that approximately 150MB is required per month per aircraft - then the most economical solution might be to utilize 2 SIMs at $20 per SIM giving a total monthly usage allowance of 200MB.
I.1.4. Using more than one SIM also provides some redundancy in the very rare event of a malfunction or abnormal issue with one or another SIM, network or bill payment thereof.
J.1. We have Boeing Series B737-400, -700, -800, 777 and Airbus Series A310, A319, A320, A321, A330 and A340. How can I install WQAR to these aircraft, STC or SB?
J.1.1. Teledyne's Wireless GroundLink® (or WQAR) is type certified by Boeing on B737NG and B777 and by Airbus for single-aisle, long-range and A380 aircraft. Therefore, for any new aircraft purchase, WQAR should be requested as BFE.
J.2. What are the changes on the aircraft side?
J.1.2. Airbus has responded to requests from individual airlines for a WQAR SB on single-aisle aircraft. Since they are requested by individual airlines, they tend to be aircraft specific and applicable to existing SBs, so your aircraft cannot be guaranteed. Some airlines add the WQAR to QAR provisions, and some add the WQAR to DAR provisions. Our experience has shown that lead times are around 6-12 months. Manuals will be updated as part of the package. Airbus has not produced a WQAR SB for A310. Airbus has supplied an SB that adds the WQAR to only the DAR provisions on long-range aircraft.
J.1.3. Boeing does not offer SBs for WQAR on B737NG and B777 aircraft. There is a customer support entity available that will apparently offer SBs for WQARs, but we expect that our STC will be cheaper.
J.1.4. Teledyne has produced STCs for WQAR on all of the aircraft mentioned and Teledyne can create STCs to meet your needs. STCs will be cheaper than SBs and are likely to be quicker to deliver. Teledyne requires a range of aircraft documentation in order to identify the scope of the modification.
This will be different for each aircraft, and it depends on what the WQAR is required to do.
Basically, if there is a 4MCU tray for a QAR on the aircraft, the WQAR is installed in this tray. Extra wires are added between the connector in the tray and two sensors in the aircraft. There is an interlock function inside the WQAR that ensures that there is no cell phone operation in flight (part of the type certification by Airbus) and these wires are connected to systems that indicate that it is safe to transmit at the end of the flight, e.g. "door open" and "air/ground". If there are no QAR provisions, our STC will cover the addition provisions.
Decisions need to be made, such as:
Our survey of the aircraft documentation will reveal what is possible and what is needed.
K. Receiving WQAR data
- If Airbus aircraft, what dataframe needs to be recorded, QAR or DAR?
- Does the WQAR need to record ACMS message data?
K.1. Do you offer a data retrieval ground facility or is it located at airline locations?
WQARs require ground-based software to receive the transmitted data. The majority of airlines install this Wireless GroundLink® Communications Manager (WGCM) software on PCs within their own facilities. Teledyne does host the WGCM software within our facility, but a link is still needed between Teledyne's servers and airline servers so the data can be replayed and processed.
Ryanair is an example where their entire fleet transmits their recorded flight data to Teledyne's facility in London. We process the data and make the parameter data, animations, event information and statistical analysis tools available to Ryanair and their expert contractors using secure internet connections. This service is also offered to other airlines if they choose to transmit their data to Teledyne.
L. Data speed/throughput and connectivity
L.1. If we install this equipment on one of our aircraft, do we have an option to activate only cellular in the region of Turkey alone for example?
Yes. The WQAR is configurable, and we will assist you with programming the defined required options before delivery.
The Options are:
L.2. Please provide more details about other kinds of data that the WQAR can send over the network connection from other aircraft equipment to the back office, including software parts and EFB data.
- No roaming: Whenever the aircraft destination is an airport in Turkey, the data will be transmitted. There is also a feature called "Download on Demand", so even if this configuration is selected and there is a desire to collect the data, even if the aircraft is outside Turkey, an operator will still have the ability to command a one-time override of the non-roaming configuration per flight so that critical data can be transmitted on occasions that warrant the need to access the data.
- Unrestricted roaming - The data can always be transmitted from any airport worldwide.
3. Restricted roaming - If an airline has a relationship with a cell phone service provider that provides cheaper roaming in certain countries, parameters can be configured on the WQAR to restrict the coverage area to match the appropriate provider's service area to transmit only within the provider's defined country boundaries (max 20 countries).
L.2.1. When the flight has ended, the cellullar radio signal inside the WQAR will make a data call to the PC with the installed WGCM software that's located in the back office. This cellular connection is a bi-directional network connection, just like a data card in a notebook PC (but with more bandwidth). This connectivity is the "Wireless GroundLink®" technology, which enables the wireless connection to be made any time the aircraft is on the ground and powered, the cellular radios inside the WQAR are also always powered on during this time.
L.2.2. The WQAR also has an Ethernet port, and software will be available soon to enable the port. Another software application will also be released to allow the transfer of data received by cellphone from the back office to be transmitted to other equipment on the aircraft. Wireless GroundLink® technology makes the aircraft a node on the corporate network for reliable connectivity.
L.2.3. Examples of WQAR connectivity to "other equipment" are:
M. WQAR Support
- Teledyne's EFB The back office can transmit updated charts, documents and NOTAMs from the ground to the EFB through the WQAR. Air Safety Reports, Journey Logs and Tech Log information can be transmitted from the EFB in the cockpit to the back office through the WQAR.
- Teledyne's Enhanced Airborne Data Loader (eADL): Instead of physically moving floppy disks around the airline and from aircraft to aircraft, the WQAR can transmit FMS Navigation database uploads, ACMS updates and other suitable software can be transmitted from the back office through the WQAR to the eADL for storage and upload into the destination equipment.
M.1. What is the guaranteed MTBF?
Users of the current generation WQAR have experienced an MTBF of 10,000 operating hours. If there is a need for a contract to include a guaranteed MTBF, then this will be included in the formal proposal activities.
N. Network Connectivity
N.1. Who initiates the connection to the cell network? The aircraft, the ground server or are both ways possible?
During normal operation, each cellular device (between 1 and 8 depending on the WQAR part number) in the WQAR initiates a connection with the cell network and then to the ground server when your aircraft lands. You can further restrict the WQAR to only establish connections which meet your specifications. These specifications are usually based on the financial decisions of your airline and are implemented through the use of roaming setting restrictions. The WQAR can even regulate specific cellular networks. However, despite these restrictions, you can direct the WQAR using the ground server, to override them on an exception basis. We call this solution "Download on Demand" (DoD), which is typically used when the aircraft has landed in a (foreign) country where the WQAR is configured (for cost reasons) to NOT routinely connect to the ground server. For example, if you have a flight on its way to a country where you do not normally transmit data, and it experiences a hard landing, turbulence or other aircraft issue, you can direct the ground server to send a coded text/SMS message(s) to the WQAR which commands the unit to transmit your flight data. Once transmission is complete, the pre-configured restraints are put back into place and the unit returns to normal operation mode.
N.2. What is the addressing scheme? Do you use Public or Private Addresses / Static or Dynamic?
The Ground Server has a static IP address which is also stored in all the WGL units. The Ground Server itself can have a public or private address but it must be visible on the outside with a public static address. Your IT department will need to open three UDP ports in your external router(s) and/or the firewall(s) for the system to function properly. Each mobile device (up to 8) in the WQAR will automatically be assigned an IP address, via your SIM provider's DHCP server, as each device creates a connection to the cellular network. Most airlines today use this method since having static addressing on the WQAR brings no additional advantage except perhaps some extra security in some respects. Note that each WGL unit will have multiple IP addresses depending on how many radios are in use (up to 8).
N.3. If dynamic, who handles the DHCP? The operator or the airline?
Again, the Ground Server uses a static address which is assigned by your IT department. Your provider's DHCP server will automatically assign any IP addresses to the WQAR as each mobile device creates a connection. However, you may make special arrangements with your SIM provider to assign static IPs to each SIM if you wish.
N.4. Does your solution implement APN the same way a GPRS mobile phone does?
Yes, the solution typically uses the cell network's consumer APN for wireless data devices. Airlines may elect to get a Private APN from the cell network for additional security. However, only one or two of many WGL customers have done this to date and most use the standard cell network consumer APN.
N.5. Does the WGL add a security level to the exchanges (authentication) or does it rely on the common GPRS security policy?
The WGL system does not rely on GPRS security. Flight data is compressed and encrypted using proprietary technology. The compression is loss-less and can achieve anything from 4 to 1 or 20 to 1 depending on the aircraft type and data frame. The encryption technology was developed by a Teledyne sister company for a US government program and is not public information, as is the case with many other encryption algorithms. Additionally, there are further security measures provided for data packets transmitted in parallel across multiple cell device connections and in a random sequence. There is companion software provided with the Ground Server which enables automated decryption and decompression and seamless integration into the Ground Data Replay & Analysis Server (such as Teledyne/Airbus' AirFASE® system).
O. Equipment Service Support
O.1. Where do I send WQAR units for SIM card exchange or for repair?
Teledyne Controls has two offices which support these services:
El Segundo Service Center
Repair Center for all other Regions
501 Continental Blvd.
El Segundo, CA 90245
Attn: Bert Matsuzaki
Customer Repair Dept
24x7 Hotline: +1-310-765-3602
Capabilities: Manufacturing, Repair, Customer Administration, Customer Support (all products), Sales & Service
9-13 Napier Road
Wardpark North Industrial Estate
G68 OEF, Scotland
Attn: Gerry Hamilton/Alan Blain
Phone: +44 (0) 1236-458-555
AOG Hotline: +44 (0) 7699-391-535
Capabilities: Overhaul & Repair, Customer Administration
Note: Advance arrangements should be made via Teledyne Product Support if a WQAR unit is sent back for SIM exchange.
QAR - Quick Access Recorder
WEP - Wired Equivalent Privacy
WPA - Wi-Fi Protected Access
DES - Data Encryption Standard
SSID - Service set identifier
SIMS - Subscriber Identity Module (SIM)
GTP - GPRS Tunneling Protocol
MTBF - Mean Time Between Failures
DHCP - Dynamic Host Configuration Protocol