Business jets equipped with older Honeywell Laseref II and III inertial reference systems (IRS) face an expensive obsolescence problem, but a solution is available. This isn’t a new issue as Honeywell has been warning owners and operators about it since 2016, but there are still hundreds of perfectly flyable jets equipped with the older Laserefs that will need an upgrade if any of their IRSs fail. In February 2019, Honeywell notified operators that repairs and rentals of Laseref IIs and IIIs would end.
The main problem for these aircraft is that the Laseref II and III units are no longer repairable because parts are not available, explained Trent Tseunis, Honeywell Aerospace director of offering management for navigation and sensors. Customers enrolled in Honeywell’s Maintenance Service Plan (MSP) Avionics coverage do have support for repairs until the end of this year, but then they will have to do what all operators with Laseref II and III IRSs will need to do: upgrade their systems.
There are 965 business jets affected by the Laseref situation, according to Duncan Aviation western regional avionics sales manager John Spellmeyer. Most of these jets are fitted with three Laserefs, but some have two, and the total number that will need to be replaced is more than 2,500, he said. Among the airplanes affected are Gulfstream IVs and Vs; Bombardier Globals and Challenger 601s; older Dassault Falcon 900s and 2000s; and Embraer Legacy 600s and 650s.
The upgrade path for any of these jets is Honeywell’s Laseref IV (modern jets are already up to the Laseref VI). The IV is a simple replacement for the III with no modification required. A small rack adapter is needed to swap out a IV for a II, plus a couple of pins need changing. STCs are available for these upgrades.
Only a failed Laseref II or III needs to be swapped for a Laseref IV, so there is no need to replace two or three at a time. However, Honeywell is offering significant discounts for the Laseref IV upgrade, and it might make sense to get them all done soon. According to Honeywell and Duncan Aviation, “Customers who wish to upgrade to the Laseref IV with Duncan Aviation are eligible for a $52,500 Honeywell trade-in credit plus attractive promotional pricing.”
“Sooner or later, [operators] are going to have to deal with this,” said Spellmeyer. “Now till the end of the year, Honeywell is offering promotional pricing and trade-ins for each unit. It cuts the cost to less than half. We’re saying do this now while the incentives are available. If you wait, you will pay twice as much.”
There is another advantage to upgrading because the Laseref IV is much lighter—about 25 pounds less than the II and 10 pounds less than the III. So upgrading three IRSs could net a payload improvement of 30 to 75 pounds. According to Honeywell, other benefits of the new IRS include "automatic realign function for postflight alignments for quick turn and auto-calibration of sensors to maintain optimal performance over time.”
Of course, the big benefit of upgrading to the Laseref IV is that it “will probably outlast these airplanes,” said Tseunis. “The IV has no obsolescence issues. We don’t foresee we’ll have to deal with this relative to these aircraft.”