My view is it's nice idea, maybe, but not workable in the real world. Shanwick and Gander will assign you a speed so there's about 3000 miles where you don't have the flexibility to speed up. In the CONUS you can leave MIA and get speed limited before you pass Jacksonville on your way to JFK or BOS. I've been slowed down on the way to LAX as far back El Paso. Sooo many obstacles when you're in a hurry. Eric
> On 09/17/2025 5:42 AM EDT srbrown via Mifnet <mifnet@lists.mifnet.com> wrote: > > > Increasing speed by 15-20 kts for the entire journey might reduce stress on > the schedule but it certainly wouldn't on the aircraft. Six knots of airspeed > equates to about 0.01 Mach, so to achieve that 15-20kt speed increase you > have to fly an extra 0.03 Mach. > > In the real world - using an A330 as an example - this means increasing the > "normal" cruise mach of M0.82 up to M0.85. That's a huge increase, bearing in > mind the aircraft's MMO is only M0.86 (MMO=maximum mach number or "red line > speed" if you prefer). We occasionally flew a "high speed cruise" of M0.83 > for scheduling purposes but you could start to "feel it" through the > airframe. At M0.84 the airframe definitely started vibrating and oscillating > a bit so you didn't really want to go there. The fuel penalties flying at > M0.83 were significant, about a couple of tonnes on a medium to long flight. > At M0.84 they'd be huge, so any company doing that regularly would have Greta > Tunberg posting elk droppings through the CEO's letterbox. You also wouldn't > want to encounter turbulence at those mach numbers either. > > I gather the A350 and B787 fly a "normal" cruise mach of M0.85 so they'd both > need to fly at M0.88 to get that extra 15-20 kts. The A350 red lines at M0.89 > and the B787 at M0.9, so they'd both be up against their aerodynamic walls > too. > > My view is it's nice idea, maybe, but not workable in the real world. I now > anticipate someone posting how epic and rugged the venerable 747s were at > winding the speed up, with a teary nostalgic mist in their eyes, and I'm sure > they were, but we don't fly those types anymore any any beancounter who's job > it is to calculate fuel costs will remind us why. > > Simon > > -------- Original message -------- > From: ATHGroup--- via Mifnet <mifnet@lists.mifnet.com> > Date: 16/09/2025 17:27 (GMT+00:00) > To: David Wardell <mifnet@lists.mifnet.com> > Cc: "athgr...@baiada.com" <athgr...@baiada.com> > Subject: [Mifnet 🛰 74151] Standard Airline Linear Thinking > > > > > I was on a flight from Europe to the US west coast and it was 1 hour late. > The inbound crew landed 7.5 hours late and needed additional crew rest. > > > > After doing some analysis, it seems that both the inbound flight and my > flight were flight planned at normal speed since the actual flight time was > within a couple of minutes of schedule. > > > > Standard airline linear thinking - fly the flight plan regardless of the “day > of” conditions. > > > > And while I don’t have the information on why the inbound light was so late, > the solution to land my outbound flight back in the US on time is simple. > > > > The flight time for the inbound flight was 11 hours, and 12 hours for my > return flight. So, to have my flight land on time, the inbound and outbound > (23 hours total) would each need to gain 3 minutes per hour of flight or > speed up about 15 to 20 knots. > > > > Would this use extra fuel - of course, but the reduced stress and connections > made would most likely make that up and more. > > > > And to add insult to injury, the flight pushed back 11 minutes after the crew > was legal because the boarding process was slow. > > > > The airline should have done a business analysis of the connections and > flight time to drive the landing time. Unfortunately, these are not > calculations airlines make. > > > > Michael > > xxxxxxxxxxxxxxxxxxxxx > > R. Michael Baiada > > cell - (303) 521-6047 > > rmbai...@greenlandings.net mailto:rmbai...@greenlandings.net > > > > -------------------------------------------------------------------------- > Revised: 20250507 > > You are receiving The Mifnet because you requested to join this list. > > The Mifnet is largely a labor of love, however the infrastructure isn't > exactly cost-free. 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