Describing the cockpit avionics in today’s regional jets can be either straightforward or complex. It is straightforward if one deals with the dominant airframes from Bombardier and Embraer, where standardization across the model ranges is the golden rule.
But the task would get complicated if one attempted to cover the variations in the older aircraft types from Avro, Fokker, Dornier and others, most of which employ a mix of current and earlier-generation avionics units. Newer concepts and technologies, such as required navigation performance (RNP) and electronic flight bags (EFBs) also complicate the regional jet cockpit picture, though they would enhance safety and performance. More on this later.
To simplify this review, we recognize that the number of regional jet airframes is rapidly dwindling and therefore focus on two major airframe families.
Why Standardized Cockpits?
First, the obvious question. Why standardized cockpits? There are several reasons, all of which are tied to operator economics. The standardized cockpit is designed by the airframe manufacturer to meet virtually all the customers’ operational needs and all regulatory requirements. This usually means the requirements of the Federal Aviation Administration (FAA) and/or the Joint Aviation Authority (JAA)-even though these may not necessarily apply in the end customer’s operating environment.
The manufacturer also must consider and, where economically practical, make provision for upcoming or proposed changes in those regulatory requirements, to reduce later retrofit costs. In other words, the aircraft must, on delivery, be virtually capable of flying anywhere in the world. And if the aircraft is later resold to another regional operator flying the same type, the new owner should be able to integrate it immediately into the new fleet.
Standardization also extends to the avionics manufacturer. Bombardier, for example, has opted for a Rockwell Collins package, while Embraer has opted for the Honeywell equivalent. This means that the operator only needs to deal with one prime avionics supplier, which in turn can offer comprehensive, and usually cost-saving, service programs tailored to the operator.
Both airframe builders have maintained their standard avionics packages even though their aircraft types have progressively changed. Bombardier, for example, offers the Rockwell Collins Pro Line 4 in its CRJ-200, -700 and -900, while Embraer offers the Honeywell Primus 1000 in its ERJ-135, 140 and 145. This yields important efficiencies in the operator’s avionics service shops, where fewer individual spare units and parts need to be held, and faster repair turnaround times can be achieved. Commonality also reduces the need for constantly renewed technician training on new systems.
Cockpit commonality is a vital safety element in an operator’s pilot training and refresher programs, as well. As one who once flew with a major airline, which operated three identical aircraft types-each with a different cockpit layout and avionics-this advantage cannot be overstated. In critical situations requiring rapid responses by the crew, hesitation or uncertainty about correct system operation can be fraught with danger. Conversely, a common cockpit layout with common systems means that pilot transition from one aircraft type to a larger, "sister" type-where only "differences" training is required-can achieve significant cost savings while yielding equally valuable, though perhaps less tangible, safety benefits.
The CRJ and ERJ Avionics
Both Bombardier and Embraer have opted for well proven avionics packages in their regional jets. With just one exception, both have remained exclusively with one manufacturer: Bombardier with Rockwell Collins and Embraer with Honeywell.
The one exception is Bombardier’s use of Honeywell’s enhanced ground proximity warning system (EGPWS, also known by the more generic acronym, TAWS, for terrain awareness warning system). Possibly, Bombardier’s hand was forced here, since Rockwell Collins did not offer an equivalent when the original package was developed.
The packages are virtually identical in scope and overall capabilities, underlining the very competitive market in which Bombardier and Embraer operate. Neither wishes to give an inch on avionics performance, but neither wants to add additional units or capabilities to the standard packages and risk adding cost or weight. No prisoners are taken in the regional airline sales arena.
The packages are also composed of what might be called "middle-of-the-line" products, designed specifically to fit into the confined quarters of an RJ’s avionics bay and adjacent small spaces. But although smaller in size, somewhat lower in cost, and lacking some of the sophistication of their larger airline counterparts, these products yield little in performance. What’s more, they are built to fully handle the day-in, day-out requirements of regional airline operations, which must be one of commercial aviation’s most rugged environments. For example, the average RJ’s avionics will experience as many as five or more takeoffs, climbs, cruises, descents and landings in a working day. These flights invariably are accompanied by more turbulence, pressure and temperature changes than those of large transoceanic widebodies. Reliability must also be high but, if a failure occurs, a system must be capable of fast and accurate diagnosis and rapid line replaceable unit (LRU) exchange during the aircraft’s very short turnaround times.
HUDS and Other Options
Despite standardization, of course, many operators want additional or upgraded avionics systems aboard their aircraft to meet particular requirements. Some options are virtually standard today, like the aircraft communications addressing and reporting system (ACARS) and equipment for reduced vertical separation minimum (RVSM). Others include conventional add-ons like a third VHF communications transceiver, or radios with 8.33-KHz channel spacing for European operators, or dual instead of single flight management systems (FMS), or an additional radio altimeter for low-visibility redundancy, or an upgraded weather radar with, say, a turbulence detection feature. These and other commonly requested options are usually accommodated without significant cockpit modification, although they all do have attendant costs.
Currently, the major RJ avionics cost option is the installation of a head-up guidance system (HGS) and its accompanying inertial reference system (IRS). The IRS — in both Embraer and Bombardier aircraft, the Honeywell Laseref IV IRS — is a requirement for HGS operations, since the standard attitude heading reference system (AHRS) is not sufficiently accurate or stable. Both Bombardier and Embraer aircraft have been fitted with Rockwell Collins Flight Dynamics HGS units, primarily for European regional airline customers, most of whom operate to much lower landing limits than their counterparts in North America.
Horizon’s Cat III Operations
The one exception in the U.S. is Horizon Airlines of Portland, Ore., for whom Cat III operations are essential in the frequently fog-bound northwestern United States. And this does not just include landings. Horizon’s HGS approval also covers very low-visibility takeoff limits.
Hence, the interesting spectacle at Seattle of a Horizon Bombardier RJ (or, for that matter, one of the company’s Dash-8s, which are also HGS/IRS-equipped) taking off and instantly disappearing into the murk, while the very latest Boeing and Airbus products sit at the end of the runway, waiting for the visibility to improve.
However, with a price tag reportedly close to $500,000 uninstalled, the HGS/IRS option is not easily justified in other less demanding parts of North America, although Air Canada and its Jazz subsidiary carry this option in their Bombardier RJs.
Customers can, of course, order any additional avionics they wish for their aircraft, whether or not they are offered as options. However, as all regional airline managers know, requesting the installation of an avionics unit or system that the aircraft manufacturer has not handled before invariably calls for a supplemental type certificate (STC) and other processes, along with sometimes remarkable amounts of time and money.
Future Avionics
There are several new systems that seem likely to enter each RJ manufacturer’s list of standard or optional items one day. Honeywell’s recently introduced Runway Awareness and Advisory System (RAAS) appears to be an early candidate, as a software upgrade to the company’s EGPWS, already standard on both regional jets. Electronic flight bags also are becoming popular. But integrating different manufacturers’ EFB software with the FMS can be a stumbling block, and retrofits in older aircraft have been cited as costly. At some time in the future, FAA and overseas required navigation performance criteria may call for upgraded FMS computers, although Bombardier’s RJs already meet Eurocontrol’s Precision RNAV (PRNav) +/-1-mile accuracy standards. And automatic dependent surveillance-broadcast (ADS-B), already increasingly used in Alaska, is expected to migrate to the lower 48 within four years.
Other systems remain uncertain. With the recent setbacks in FAA’s local area augmentation system (LAAS) project, an unanswered question is whether the wide area augmentation system (WAAS) will become a regional carrier approach aid at non-ILS airports. FAA appears undecided, and therefore so are operators, avionics firms and airframe manufacturers.
Lowering the Decision Height
The same appears true of infrared (IR)-based enhanced vision systems (EVS), which can "see" through rain, drizzle, mist and most types of fog. While EVS is admittedly a high-cost addition to an HGS/IRS combination, a recent FAA ruling may send RJ operators back to their cost/benefit calculators. The agency announced earlier this year that EVS, when used with an HGS, could lop 100 feet off the normal 200-foot decision height of a Category I approach. Infrared industry experts feel that once sufficient experience has been gained in this area, the next step will be to allow the HGS/ EVS combination to reduce the current 100-foot decision height of Category II to perhaps 50 feet.
European regional operators probably will lead in this area, as they have with the head-up guidance system. The benefits seem clear. At a European aviation safety conference last year, Mike Ambrose, director general of the European Regions Airline Association and also an international vice chair of the Flight Safety Foundation, stated, "EVS technology potentially offers the next major breakthrough in improving air safety." He added, "It’s like giving the pilot his eyes back."
Still Expanding
Demand for regional aircraft will continue to grow during the next 20 years, according to a Rolls-Royce forecast of the 2003-2022 business outlook. The engine maker predicts a demand for 41,176 new aircraft of all types, worth about $2.18 trillion at today’s prices. Of that total demand, the world market will require 8,319 new regional aircraft-defined as having fewer than 100 seats-at an estimated value of $179 billion. More than half of the new airplanes (4,685) to be delivered will be in the 30- to 50-seat class, while the remainder (3,634) will be in the 70- to 90-seat category.
North America and Europe will account for the lion’s share-70 percent-of new regional aircraft demand. Africa and South and Central America will grow at a faster rate but from a smaller base. Regional airlines will continue to outpace the mainline carriers in short-haul markets but will increase market share at a slower rate than in recent years.
Rolls-Royce also predicts the retirement of 4,279 regional aircraft during the period. That represents 80 percent of the current fleet.
Bombardier CRJ-All Models
Rockwell Collins Pro Line 4:
TWR-840 weather radar (1)
DCU- 4000/4004 EFIS/EICAS (6 tubes)
FCC-4000/4010 Cat II AFCS (1)
FMC-4100 FMS (1)
VHF-422 VHF com (2)
VIR-32/432 VHF nav (2)
DME-42/442 DME (2)
ADF-462 ADF (2)
RTU-4200 radio tuning unit (2)
TDR-94D Mode S transponder (2)
TCAS-94 TCAS II (1)
ALT-4000/55B radio altimeter (1)
GPS-4000A GPS (1)
AHC-85E AHRS (2)
ADC-3000/850A air data computer (2)
Mark V EGPWS* (1)
*Produced by Honeywell
Embraer ERJ-All Models
Honeywell Primus 1000:
Primus 660 weather radar (1)
DU-870 EFIS/EICAS (5 tubes)
IC-600 integrated avionics computer and Cat II AFCS (2 )
NZ-2000 FMS (1)
RCZ-854E VHF com (2)
RNZ-851 VHF nav (2)
RNZ-851 DME (2)*
RNZ-851 ADF (2)*
RM-855 radio management unit (2)
RCZ-854E Mode S transponder (2)**
RT- 951 TCAS (1)
RT-300 radio altimeter (1)
HG2021GD02 GPS (1)
AH-900 AHRS (2)
AZ-850 air data computer (2)
Mark V EGPWS (1)
* DME and ADF integrated with VHF nav in RNZ-851
** Mode S integrated with VHF com in RCZ-854E