CLAIM: Gulfstream G500 and G600 “can’t land in wind”
 

I apologise in advance if this topic has been previously covered. I have just seen a report in a general news newsletter headlined “Flier’s Remorse” about the Gulfstream G500 and G600. According to the blurb “Gulfstream’s new G500 and G600 private planes offer every luxury—marble counters, living rooms, multiple sleeping areas—except the ability to land in wind.”

The report is behind a paywall. Here are the main points made in the report:

1. “According to a source familiar with Gulfstream aircraft, the G500s and G600s have a glitch in their computer software that can send these planes into a nosedive if their pilots try to land in winds stronger than 15 knots.”
2. “A private-jet consultant who represents several Gulfstream owners estimates the flaw could impact 75 percent of his clients’ trips. “So [let’s say], for example, you’ve just got this $55 million plane,” he tells me, “and you’re supposed to go on vacation to the South of France. But the wind is forecast to be in excess of 15 knots upon landing. Guess what? You can’t go.””
3. “Lawyers have started talking about class-action lawsuits. According to one source, some prospective owners have canceled orders until the problem gets solved.”
4. “Another owner, who requested anonymity, explained that he’s outraged not only because his private jet is unusable, but also because of the recurring fees and costs that have racked up while the plane has been grounded. “You pay $40-plus million for your aircraft. You employ pilots, you employ a mechanic. You have to pay for a hangar and all the other ancillary costs, which are fixed expenses,” he explained.”
5. “The owner estimates that the plane costs him $300,000 a month. “It’s a terrible situation. I’ve talked to the president of Gulfstream [to say], ‘basically, you’ve rendered these planes unreliable.’”
6. “A spokesperson for Gulfstream says the company has “proactively communicated with all G500 and G600 owners and remains available for any needed support.””
7. As of now, the consultant says, the planes “literally can’t land” in anything other than optimal conditions. “You spent all of this money, and you’re stuck with it,” he says.
8. “A spokesperson for the company said Gulfstream “has been working closely with the F.A.A. on a software update” which “has been completed and we anticipate F.A.A. approval and subsequent deployment later this year.” But that will likely be long after the vacations many of Gulfstream’s owners have likely planned.”

Does anyone know what is going on here?

https://www.aopa.org/news-and-media/...on-limitations

https://www.govinfo.gov/content/pkg/...2022-09925.htm

Surely it should say "deal clinching trip" rather than "vacation"?

How can something like this not have been caught during flight testing and certification? US aircraft manufacturers seem to struggle with AoA limiters as of late.

I believe the issue is caused when the pilot “over-handles” the controls during landing in gusty or “more challenging than usual” wind conditions and the resultant behaviour of the FBW flight controls is less than ideal. The problem (for Gulfstream and the owners) is that the FAA is requiring a line-by-line verification of the entire FBW software coding before approval - this because of the 737 Max saga… This is a very lengthy process and will take a while to achieve. I understand why current and prospective owners of these jets would be displeased.

Finally explains why all the Qatar G500's went back to the manufacturer

That's indeed rather surprising.
What was the xwind limit before this surfaced?

Firstly, the 15kts is a TOTAL wind limitation, not a crosswind. And within that 15 kts is a maximum gust of 5kts! Challenging conditions indeed.
Once the software fix has been uploaded (September/October) the limit will revert to a ‘maximum demonstrated’ of 30kts.

Along with the wind limit is an approach speed limit - approach to the threshold at ref+10, which again has a huge impact on landing distance especially in the wet.

The original heavy landing resulted in a 22kt crosswind limit and min speeds of ref+5 (FAA) and ref+10 (EASA). Bizarrely, in the second instance that cause the more dramatic AD, the pilot didn’t appear to be adhering to the original limits.

The cause is rapid ‘push pull’ inputs on the sidestick (full fore/aft 4 times in under a second) coupled with ‘sideslip’ cause erroneous activation of the pitch limiter. As for why this hasn’t been spotted by Gulfstream during testing, join the long line of people asking that question, including I suspect a number of Lawyers!

The G700 has also been delayed as a result. It has similar software but the new FAA requirements for ‘link by line’ model based testing have delayed its approval.