- 19 Feb 2024
- Ken Elliott
- Avionics - BizAv
Ken Elliott explores different pathways for common business aircraft cockpit upgrades, this month reviewing the Collins Aerospace Pro Line 21 retrofit...
Back to ArticlesDuring a potential pre-owned aircraft acquisition the primary avionics suite is inevitably a purchasing consideration. More than likely, the suite will originate from a single avionics’ provider that, in collaboration with the aircraft manufacturer, had tailored a specific electronic platform for each make and model of aircraft for which it was contracted.
One common avionics suite that can be found in business aircraft is Collins Aerospace’s Pro Line 21. The staging of the Pro Line 21 avionics panel (see Figure A below) is mostly represented by:
Aircraft models evolve over time, and it is rare for the airframe manufacturer to commence from a clean sheet design. Modern aircraft manufacturers form alliances with suppliers and develop long-term relationships. Together, they will mock-up a cockpit, simulating realistic pilot experiences while conducting virtual flights.
The primary avionics will advance over generations of progressive aircraft to accommodate new technologies, emerging airspace requirements and cater to ergonomic improvements.
FIGURE 1: The Staging of Collins Aerospace's Pro Line 21 displays and controllers in a
Bombardier Challenger 605 business jet
For newer aircraft, irrespective of the avionics suite it should be noted that after delivery their avionics are not frozen in time. Service Bulletins (SBs) and Aircraft Service Changes (ASCs) are issued to undertake required and optional alterations as they arise. These include:
For pre-owned aircraft, it is very common for the buyer to be faced with an aircraft that is still equipped with its original avionics package. Even though it should already be upgraded for operational mandates such as ADS-B Out, TCAS II Change 7, ELT, standby instruments and more, its primary equipage will remain the same.
When a major upgrade – such as Pro Line 21 suite – is made available as an option, there is less incentive to invest in the potentially significant finance involved. However, when the displays face obsolescence or the owner is unable to meet an emerging airspace requirement, these circumstances necessitate an upgrade.
All Pro Line 21 upgrades will be installed and certified either via an existing Supplemental Type Certificate (STC), or factory TC amendment. They will all consist of baseline equipment and multiple additional options.
If you are considering such an upgrade it is important to know that the Pro Line 21 interfaces significantly with existing remote systems that must be compatible and may, themselves, require updating.
Collins Aerospace Pro Line 21
A long established, highly regarded provider of avionics, Collins Aerospace (formerly Rockwell Collins) produces the Pro Line 21. Commencing generations ago with Pro Line I analogue avionics, Collins has progressed through to digital avionics in the Pro Line 21 and the later Pro Line Fusion series.
The predecessor of the Pro Line 21 is the Pro Line 4, and upgrades usually replace either a Pro Line 4 or earlier Pro Line II package.
Collins has provided the Pro Line 21 as the primary avionics in new build aircraft, making it available for upgrade on pre-owned aircraft too. The Pro Line 21 is tailored to specific aircraft types and models that in some cases may be serial number specific.
It is, therefore, recommended that you consult with your preferred avionics facility (that may also be the aircraft OEM) to ensure a Pro Line 21 offering is applicable to your aircraft, and that any additional requirements are included and priced.
Keep in mind, too, that all equipment providers and shops that install avionics have been faced with procurement and labor challenges. Ensure you allow plenty of time for any major upgrade package, and if you’re purchasing a pre-owned aircraft, be prepared to take delivery first and then schedule an upgrade.
How Pro Line 21 Works
Viewing the Adaptive Flight Displays (AFDs) and entering data via the DCUs and CDUs, the pilot prepares for a flight by selecting trip details to navigate using the FMS. They set frequencies and modes to manage Communications, Navigation and Surveillance (CNS), select display modes for the onside AFDs and choose a flight control mode into a separate glareshield mounted controller.
The AFDs help to declutter the cockpit and typically consist of four displays. The PFDs provide traditional, but much enhanced Flight Director (FD) and Horizontal Situation Indicator (HSI) data directly in front of the pilot(s), while the MFDs provide systems synoptic data, flight charts and route maps, graphical and XM weather and diagnostic pages.
Reversionary switching is available between the various flight displays, as needed. Pro Line 21 AFDs are manufactured in different flavors, each with a dedicated part number. While earlier versions have image selections on the displays themselves, later versions are fully remote controlled from separate Display Control Panels (DCPs).
Model designations ending in ‘E’ have internal ethernet cards, essential for Integrated Flight Information System (IFIS) functionality.
For many pilots, the operating differences between a Pro Line 4 and Pro Line 21 are not major. However, between the earlier Pro Line II and Pro Line 21 operation is significantly different, moving from analog to digital functionality.
In either case, the remote avionics interfaced to the Pro Line 21 are much the same as before (in that CNS and flight controls remain operationally similar). It is having modern displays and the addition of new features that catch the attention of, and provide huge benefits to, flight crews.
So, while the big draw is the cockpit displays, what they enable in additional features and electable options – including the ability to meet new operating requirements – can drive an upgrade decision.
Pro Line II equipped aircraft included Line Replacement Units (LRUs) as dedicated hardware ‘boxes’ for each sub system, and some early aircraft are still equipped that way. Later aircraft were completed with module ‘cages’, housing ‘cards’ that individually serve as a sub-system.
Data is transferred between systems on common ARINC busses, specialized by technology and given unique designations, such as ARINC 429. Data concentrators direct electronic traffic along the way.
TABLE A: Matrix of Pro Line 21 Upgrade Options for Various Aircraft Types
An Overview of Pro Line 21 Features
Apart from new displays and their arrangement, there are several exclusive features available with a Pro Line 21 upgrade. Some are baseline and some optional.
Pricing commences with the baseline package for each model of aircraft, then each available option is offered on an individual, additional fee basis. Bundling of options may sometimes be offered.
Baseline Pro Line 21 Features
Navigation & Charting-related Baseline Features
• Integrated Flight Information System (IFIS) providing:
- Enhanced maps with airways, intersections and geopolitical boundaries
- Own ship position on electronic charts
- Split chart displays for improved chart coverage
- Satellite weather
- Chart-Link or e-Chart to FMS flight plans
- Geo-referenced airport diagram upon landing.
Surveillance-related Baseline Features
Optional Pro Line 21 Features
The following optional Pro Line 21 features are available with additional equipment and integration, where all equipment is available from Collins Aerospace. Some aircraft will be delivered with options as baseline, and some options are not available for specific aircraft.
Depending on the size, capability and operational scope of the aircraft, some options may be considered impractical.
General
Communication-related Options
Navigation & Charting-related Options
Surveillance-related Options
Note: ADS-B Out Version 2 is an option but should by now be installed on aircraft as its mandate date has passed in most regions. Check that your ADS-B solution is Version 2.
Additional options for cabin and connectivity:
Additional options for flight support:
- International trip support
- Flight Operations System (FOS)
- Flight planning
- Connectivity services.
Pro Line 21 Upgrade Considerations
For any major avionics upgrade, each type and model of business jet will have unique characteristics that could be as simple as the level of software in a specific avionics system.
Once an aircraft has delivered, it will begin to develop its own history and may undergo modifications, improvements and additions that other aircraft of an identical build, don’t.
Further, aircraft manufacturers will ‘cut in’ changes to avionics during a production run, such that from a certain serial number forward, the change becomes standard. That change may also be available as an optional service bulletin or modification to earlier serial numbers.
FIGURE 2: Various Remote Pro Line 21 Avionics and Aircraft Systems
Each of the previous situations can impact a major avionics upgrade in the following ways:
To reiterate, it is very common to encounter situations where an upgrade, as promoted, is not one-size-fits-all. For this reason, pricing, downtime and certification cannot be assumed.
It is more important to try to approach your preferred service center with adequate information, enabling them to provide an accurate estimate, and to forewarn you of potential issues including extra downtime or costs.
When estimating a PL-21 upgrade, the salesperson will typically engage engineering, certification and other specialists to ensure nothing is overlooked. Compatibility of existing avionics is of paramount importance, and although the model of a sub-system may be correct, its part number or modification status (either hardware or software), may not be.
Some of the key pieces of information most useful to the service center for quoting and completing an upgrade are to know your existing equipment. You should be able to produce part numbers, serial numbers, modification, and software level of all dedicated hardware. This is facilitated by up-to-date aircraft logbooks, modification records and equipment lists.
Maintain your certification records. Since delivery, any change to your aircraft should be accompanied by applicable certification data – from wiring diagrams to repair or service bulletin records. These should be retained by operators, ready to share with a service center.
The service center should also be given a clear picture of what options you may need, based on your specific way of operating the aircraft, such as oceanic, remote, specific region, airports and routes. Do not expect the service center to automatically know your unique requirements.
Keep in mind that it is best to only open an aircraft’s interior once, reducing overall downtime and cost. If you can include any available option because it is convenient, do so. It will enhance the resale value and capability of your aircraft.
As stated, the flight crew interact with the Pro Line 21 primarily through DCUs and CDUs, while viewing current flight information on the AFDs. However, consider that a significant quantity of new, and mostly existing, remote equipage drives off, or takes instruction from, the Pro Line 21.
There is deep complexity to business aircraft electronics, and both electrical and certification engineers have much due diligence to review prior to, and in support of, an upgrade.
In Summary...
Lastly, cockpit upgrades as significant as the Pro Line 21, can involve both time and some disruption. Many operators use the opportunity to add cabin updates and aircraft paint work. It will be sensible to at least consider some of the Collins cabin offerings listed previously.
The Pro Line 21 is a proven, reliable, well supported and popular aircraft upgrade. Collins Aerospace has the experience, the technology and the reputation to proudly stand behind each Pro Line 21 upgrade.