Quiet Technology Aerospace (QTA) has earned FAA/EASA approval for a repair solution to a corrosion problem plaguing operators of several midsize jets using Honeywell HTF7000 engines. The problem is a significant and recurring corrosion on the thrust reverser (TR) doors. Until now there was no option for repairing the affected doors. An operator's only corrosion-relief option was installing new OEM thrust reverser doors at considerable cost.

Aircraft powered by the HTF 7000 engines include: Challenger 300/350, Gulfstream G280, Embraer Legacy 450/500 (now Praetor 500/600) and the Citation Longitude. QTA is approved to apply their corrosion repair solution even if the TR doors are deemed to be beyond economical repair.

QTA's thrust reverser door life extension programme extends the life of the TR doors until such time as a permanent solution is finalised, approved and available. Quiet Technology Aerospace has a permanent solution under review now and is confident an approved TR door permanent solution will be available by mid to late 2021. For operators who cannot wait and need a corroded thrust reverser door repair immediately, QTA utilises its renowned engineering and technical composite experience to structurally reinforce the door back to OE limits. The life extension repair extends corrosion blend-out limits. TR doors are then painted to match the aircraft perfectly.

The repaired TR doors are light weight, and repairs can be made within two weeks. The QTA life extension repair provides maximum protection per the existing OEM corrosion service bulletin.

Martin Gardner, QTA's EVP engineering and customer support, explains: “The TR doors are made from a one piece 7075 aluminium casting. Where the jet exhaust washes across the surface in-line with each lobe of the core mixer nozzle, there is an effect called 'jet erosion corrosion'. This breaks down the molecular structure at the surface and leads to the pitting corrosion. To extend the service life we are using carbon graphite doublers to reinforce the door structurally on the inside surface, so we can safely increase the blend out limits on the exhaust side.”

Barry Fine, QTA's president, is proud he and his team are bringing this technology to the market. “Our approved repair solution to this relentless problem of corrosion on the HTF7000 thrust reverser doors is a game changer,” he states. “Finally, engineering and technology exists that can repair for now, and permanently resolve very soon, a horribly expensive and time-consuming problem that will not go away by installing new OEM doors because the underlying OEM problem hasn't been addressed. Our door life extension and permanent solution programmes mean operators have a choice when it comes to paying exorbitant fees to OEMs for maintenance service plans that do not remedy the underlying problem. Our engineering and composite technology will terminate corrosion to the TR doors. And the work will come with a lifetime guarantee that is transferable and stays with the aircraft. If a customer comes to us now with an immediate life extension repair, we will quickly handle that and give them a significant credit toward our permanent solution, which will be approved and available later this year. It's such a win-win for the operator. It's kind of a no-brainer.”