3 ms·

Correct, the headline equates to 3,500ft/min. It's about double of the usual rate of decent, but still common enough that regular passenger carriers will somet

Correct, the headline equates to 3,500ft/min. It's about double of the usual rate of decent, but still common enough that regular passenger carriers will sometimes decend at that rate.

HPsquared 3y ago
Rule of thumb is that 1 kn ≈ 100 ft/min. So 3500ft/min is about 35 knots vertical speed. Not much compared to the horizontal speed, which is closer to 500 kn.
- cameldrv 3y ago
  40mph straight down is a pretty fast rate of descent. That said there’s nothing inherently unsafe about it. If you’re losing cabin pressure, you really want to be at a breathable altitude ASAP.
  - HPsquared 3y ago
    Yeah it's definitely steep, but just to put it in perspective it's something like a 7% gradient
buildsjets 3y ago
I have been in several models of commercial aircraft during certification testing where we had to perform a max effort emergency descent as a part of the flight test profile. We routinely would hit rates of descent in the of 9,000-10,000 FPM range. I normally experienced this while strapped into a flight test workstation in the back of the plane, but once or twice had the opportunity to sit in the flight deck jumpseat. Once the aircraft is established in the descent, there is a bit of additional buffeting (light turbulence) and wind noise, but there is no highly unusual attitude involved. Initially, depending on how aggressively the pilot transitions from level flight to the descent, there can be a brief second of reduced or even zero G, but a smooth transition does not increase the total descent time by too much. I have a colleague who was involved with the flight testing of the C-17 military cargo plane. That aircraft can safely deploy all four thrust reversers while in-flight to make a high angle tactical descent - it can hit in excess of 25,000 FPM. Supposedly everyone on the test flight was supposed to have been medically cleared for this flight, but one crew member had a lingering ear infection, and blew out both eardrums during the test.
- CobaltFire 3y ago
  I did a Space-A flight with my family on a C-17. They didn't do the full thing, but they absolutely pushed that bird up and down hard, with some banking, on takeoff and landing. They warned us, and a good time was had by all. Worst landing I ever had was a dirt field in a fully PAX loaded C-130. It wasn't the descent rate, it was just the landing. No thanks.

Correct, the headline equates to 3,500ft/min. It's about double of the usual rate of decent, but still common enough that regular passenger carriers will sometimes decend at that rate.

HPsquared 3y ago

Rule of thumb is that 1 kn ≈ 100 ft/min. So 3500ft/min is about 35 knots vertical speed. Not much compared to the horizontal speed, which is closer to 500 kn.

cameldrv 3y ago
40mph straight down is a pretty fast rate of descent. That said there’s nothing inherently unsafe about it. If you’re losing cabin pressure, you really want to be at a breathable altitude ASAP.
- HPsquared 3y ago
  Yeah it's definitely steep, but just to put it in perspective it's something like a 7% gradient

buildsjets 3y ago

I have been in several models of commercial aircraft during certification testing where we had to perform a max effort emergency descent as a part of the flight test profile. We routinely would hit rates of descent in the of 9,000-10,000 FPM range. I normally experienced this while strapped into a flight test workstation in the back of the plane, but once or twice had the opportunity to sit in the flight deck jumpseat. Once the aircraft is established in the descent, there is a bit of additional buffeting (light turbulence) and wind noise, but there is no highly unusual attitude involved. Initially, depending on how aggressively the pilot transitions from level flight to the descent, there can be a brief second of reduced or even zero G, but a smooth transition does not increase the total descent time by too much. I have a colleague who was involved with the flight testing of the C-17 military cargo plane. That aircraft can safely deploy all four thrust reversers while in-flight to make a high angle tactical descent - it can hit in excess of 25,000 FPM. Supposedly everyone on the test flight was supposed to have been medically cleared for this flight, but one crew member had a lingering ear infection, and blew out both eardrums during the test.

CobaltFire 3y ago
I did a Space-A flight with my family on a C-17. They didn't do the full thing, but they absolutely pushed that bird up and down hard, with some banking, on takeoff and landing. They warned us, and a good time was had by all. Worst landing I ever had was a dirt field in a fully PAX loaded C-130. It wasn't the descent rate, it was just the landing. No thanks.