As they say, “timing is everything,” and in the case of the Bombardier CRJ aircraft, timing has been somewhat cruel. The basic 50-seat aircraft is a fine machine, in service around the world, but with its biggest presence in North America. Powered by General Electric CF34 turbofans, the aircraft was supposed to bring real jet service to markets where big planes just didn't make economic sense. Unfortunately, as jet-fuel prices began to spike a few years ago, regional jets generally began to slip over the edge of the cost-benefit curve.

During the next few years, most forecasters expect to see a large number of aircraft retired before their time. The 50-seat-class CRJs are anywhere from 15 years to as little as seven years in service, but thriftier, less-thirsty CRJ Next Generation aircraft already are lining up to take their place.

Next Generation versions of the CRJ700, CRJ900 and CRJ1000 promise operating costs anywhere from 8-15% lower than the base model CRJ, and lower emissions mean they'll be 30% greener too. All of which means you can expect overhauls of all kinds for this series to be somewhat off the pace of other, similar aircraft as early retirements take candidate aircraft out of the pool.

As an example, typically landing gear get a complete overhaul—nose gear and main landing gear—every decade. For some of the youngest CRJs, there's a good chance they'll be retired just as that overhaul comes due.

Still, there will be plenty of opportunity for work on the series, both base model and new-generation aircraft. Aviation Week Intelligence Network's MRO Prospector tool projects that SkyWest Airlines will need 58 main landing gear overhauls during the next 12 months, 37 the following year and 13 in the third year of the forecast period. The largest CRJ operator with 155 CRJs, 95 CRJ700s and 21 CRJ900s, SkyWest overall is projected to spend $4.7 million this year on heavy checks for CRJs, along with $17.6 million on C checks and $34.5 million on component maintenance on its CRJ fleet.

Pinnacle Airlines is a close second when looking at significant CRJ operators, flying some 200 of the Bombardier aircraft, including 57 CRJ900s. Pinnacle's fleet is expected to require about $5.6 million worth of heavy checks during the next 12 months, and some 82 C checks are projected during the same period, at a cost of more than $10 million. MRO Prospector projects that the airline will spend about $25 million annually on component maintenance for the next few years.

Among significant CRJ operators, Pinnacle would appear to be the only carrier with a rate of main- and nose-landing gear overhauls that would appear to be relatively steady. And of the five most significant CRJ users—SkyWest, Pinnacle, PSA Airlines, Mesa Airlines and Air Wisconsin Airlines—only Mesa has no main landing gear overhauls expected at all during the next 12 months, according to MRO Prospector.

Pinnacle is projected to need 22 main landing gear overhauls during the next 12 months, and 23 in the following year. PSA is seen needing 35 during the next 12 months, and another 14 in the following year. Air Wisconsin is projected for 29 main landing gear overhauls in the coming 12 months, but only nine in the following 12-month time period, and none thereafter.

If the Bombardier CRJ family's airworthiness directive (AD) history needed a component-related theme, “landing gear” would be an appropriate choice, and thus some landing gear work may well dominate the maintenance market for the aircraft for the foreseeable future.

Landing gear or landing gear-area issues have prompted Transport Canada (TC) to issue 10 individual or gear-related ADs in the past four years, accounting for about one in six TC directives issues against the CRJ series in that time.

On Jan. 26, 2012, TC issued CF 2012-06, requiring CRJ operators to install new sensing elements in the main landing gear wheel well and the over-wing area, protective blankets on the upper surface of the wing box and fuel tubes, as well as protective shields on the rudder quadrant support-beam in the aft equipment compartment. The fixes, which help ensure high pressure duct bleed air leaks are detected quickly, must be done by Feb. 9, 2014, or within 6,600 flight hours, whichever comes first.

In October 2010, TC issued CF-2010-36, an emergency AD mandating inspections and modifications of CRJ700 and 900 main landing gear fairing and seal to prevent interference between the seal and the gear door. The directive was triggered by two cases of main gear doors not extending fully.

TC also has issued a series of directives to prevent CRJ700 and 900 main gear doors from separating in flight. The most recent, CF-2003-23R3, mandated a terminating action based on a May 2010 Bombardier service bulletin for all aircraft built before the modification was introduced on the production line. Operators had 6,000 hours from June 9, 2010 to make the modifications.

While gear issues have held much of the CRJ AD spotlight in recent years, they haven't been alone on the stage. In 2009, TC mandated incorporation of a new elevator power control unit centering mechanism on the elevator torque tube. Operators had 6,000 hours from Sept. 3, 2009 to perform the work.

In 2007, TC issued a directive to address a series of well-publicized flap failures involving CRJ100s and 200s. Among the required procedures in CF-2007-R1: cleaning and lubrication of flexible shafts, installation of metallic seals, periodic pressure tests, specific post-flap fail event dispatch instructions, and (as a terminating action) new actuators.

Notable CRJ Series Series ADsNotable CRJ Series Series ADs
AD Issue Effective Date Compliance
CF 2012-06 Bleed air leak detection 2/9/12 24 months or 6,600 hours
CF-2010-36 MLG door fairing, seal 10/18/10 Inspections every 600 hours; repairs as needed
CF-2003-23R3 MLG door 6/9/10 6,000 hours
CF-2007-10R1 Flap failures 8/25/08 Varied based on task
CF-2009-28R1 Elevaor oscillation due to control rod disconnect 9/3/09 6,000 hours