Ask The Pilot

[jb747]

Gents, in light of the Jetstar passenger thread incident, do Pilots talk to problem passengers in which situations? Does every captain take a different way of handling it? (Ie do some go down to sort it out, vs others who just don’t get involved)

What is there to talk about? It is not a negotiation. QF training was for the pilots to keep well away from this sort of event. If the CSM, who is after all, dealing with passengers day in, day out, can’t sort it out, then calling in a person who sees the world in black and white is not going to improve things. Demanding to see the captain would be a total loser of a proposition. You’re not going to see me, but you will be leaving.

 

[Kendall Roy]

Any ideas what happened here on the 25 to HND? ETOPS issue? Bad WX?

QF25 (QFA25) Qantas Flight Tracking and History 16-Mar-2023 (SYD / YSSY-HND / RJTT) - FlightAware

Track Qantas (QF) #25 flight from Sydney to Tokyo Int'l (Haneda)

flightaware.com

 

[D747]

What are the characteristics of business jets that allow them to cruise at higher altitudes?

 

[dylarr]

Any ideas what happened here on the 25 to HND? ETOPS issue? Bad WX?

QF25 (QFA25) Qantas Flight Tracking and History 16-Mar-2023 (SYD / YSSY-HND / RJTT) - FlightAware

Track Qantas (QF) #25 flight from Sydney to Tokyo Int'l (Haneda)

flightaware.com

Interestingly the aircraft formed QF62 to BNE and did something similar on that sector coming back down south too...

VH-QPG Flight Tracking and History 17/03/2023 (HND / RJTT-BNE / YBBN) - FlightAware

Track VH-QPG flight from Tokyo Int'l (Haneda) to Brisbane

flightaware.com

 

[jb747]

Interestingly the aircraft formed QF62 to BNE and did something similar on that sector coming back down south too...

You’d need to look at the tracks taken by other airlines on the same day. If they did similar, then it’s something common. So weather, ATC, volcano. That sort of thing. ETOPS is unlikely. The aircraft would not have been despatched from Sydney with less than 2 hours of ETOPs. There are MELs that would allow such departures, but pretty much invariably they do not allow it from a main base. Even so, the track makes no sense, as you could hold even a shorter ETOPs limit with a more easterly track.

With events like this, I can normally find the details and reasons if posted within 24 hours of departure. After that they disappear into the ether.

 

[jb747]

What are the characteristics of business jets that allow them to cruise at higher altitudes?

Many things, probably the most important of which is money.

For any aircraft to get up very high, you need a low wing loading (i.e. weight vs area), and a fair bit of power. You’d also need to be able to cruise at high mach number. That implies a thin, highly swept wing, which in turn tends to be more demanding at lower speeds.…i.e. higher stall and min drag speeds. Assuming a min drag speed of 230 kias, that converts to a mach number of almost .94 at FL500. So you can’t go slower than that, and faster will definitely have you into the transonic nasties (limited control, pitch changes, drag rise).

The U-2 takes a different tack, with what is a very slow speed wing, but its stall and min drag numbers are so slow that mach number isn’t an issue until much higher.

Structurally it will have to be strong enough to handle the increased differential pressure that will be needed, and your pressurisation system will have to be up to it. Much easier in a biz jet than an airliner.

It’s not necessarily all that efficient, but the airways generally stop at F450, and airliners very rarely go above FL410, so the ability to go high could make it easier to get ATC clearances. The average pilot has no business up there though.

Airbus are limited to FL431 and modern Boeings to FL451. 99.9% of the time they couldn’t get there even if you wanted to.

 

[justinbrett]

ANA880 was around the same time and had so such diversion.

NH880 (ANA880) All Nippon Flight Tracking and History 16/03/2023 (SYD / YSSY-HND / RJTT) - FlightAware

Track All Nippon (NH) #880 flight from Sydney to Tokyo Int'l (Haneda)

flightaware.com

 

[jb747]

ANA880 was around the same time and had so such diversion.

Sorry, I'll have to leave you with a "don't have any reasonable answers" on this one.

 

[Quickstatus]

Currently there are 2 F22 and a KC tanker USAF in MEL after the AVV air show earlier this month.

I understand the F22 are heading back to DNA (Kadena Air Base Japan).

I'm assuming the KC tanker is there to refuel the F22 enroute to DNA.

What's the typical refueling speed and altitude?
Do aircraft such as Fighter Jets have issues operating for extended periods such as a mission MEL-DNA with inflight refuelling?

 

[justinbrett]

Do aircraft such as Fighter Jets have issues operating for extended periods such as a mission MEL-DNA with inflight refuelling?

Fewer issues than without the tanker

Currently there are 2 F22 and a KC tanker USAF in MEL after the AVV air show earlier this month.

I understand the F22 are heading back to DNA (Kadena Air Base Japan).

I'm assuming the KC tanker is there to refuel the F22 enroute to DNA.

What's the typical refueling speed and altitude?

They can and have done mainland US to Australia in one leg. It's not pretty at the end, but nothing stopping it. Usually for that trip though it would be broken into three legs - US-HIK(HNL)-UAM(Anderson AFB)-AU. Roughly 6 hours a piece.

The longer the leg, the fewer jets that can be dragged. We've done HIK-AUS a lot more often but you need a lot of tankers.

Lots of variables for altitude and speed, based on tanker aircraft type and refuelling method - boom (tanker penetrates the fighter) or drogue (fighter penetrates the drogue attached to the tanker). F-35s are boom but F/A-18Fs/EA-18Gs are drogue. All of the heavies (and most USAF aircraft) are boom. Our KC-30s have both methods.

Typical altitudes I see are FL200-F250ish at a slight reduction in normal cruise speed. Theoretically max altitude for KC-30 refuelling is FL350.

Quite often the fighters will slingshot between tankers, so there might be a tanker out of MEL, then another out of DRW and finally one out of UAM.

 

[jb747]

I'm assuming the KC tanker is there to refuel the F22 enroute to DNA.

I’d assume more than one tanker. As mentioned there will tankers out of a number bases along the route. They have to allow for failures along the way, not just of the tanker and its equipment, but also from the fighters. Basically they will always ensure that they have sufficient fuel to go somewhere if the tanking should fail. One effect of that is that they’ll tank up more often than you might expect. I don’t know whether they can refill the external tanks from the tanker, but I wouldn’t be surprised if they can’t.

What's the typical refueling speed and altitude?

It’s generally relatively low, as you want the fighter to have sufficient excess power to be able to easily hold accurate formation. An F22 is probably a lot more lenient than others in this regard. A friend was flying the Tornado F3 in one of the Gulf unpleasantnesses, and it was notoriously short on power. I recall him saying that they sometimes put one engine into minimum afterburner, and then used the other for the adjustments. Apparently the effect was that fuel came in only marginally faster than it went out the other end.

Do aircraft such as Fighter Jets have issues operating for extended periods such as a mission MEL-DNA with inflight refuelling?

Some pretty obvious ones. Toilet. Sleep. Toilet. Food service. Luggage stowage. Toilet. Search and rescue is something that also needs to be allowed for, so don’t be surprised if there is a P-8 or something of its ilk moving along the their track.

 

[Quickstatus]

Would the F22 supercruise (cruise above Mach 1) between tankers to reduce flight time if that is an overall benefit, or remain below Mach 1 to be fuel efficient - assuming subsonic is always more fuel efficient or at least Drag is horrendous around the transonic (mach 1)

 

[justinbrett]

Would the F22 supercruise (cruise above Mach 1) between tankers to reduce flight time if that is an overall benefit, or remain below Mach 1 to be fuel efficient - assuming subsonic is always more fuel efficient or at least Drag is horrendous around the transonic (mach 1)

Fighters on peaceful transits won't normally cruise above what a civilian airline would cruise at (around M0.85). It's terrible fuel economy, and it's illegal in most countries over land. Diplomatic clearances are hard enough to deal with as it is.

Some pretty obvious ones. Toilet. Sleep. Toilet. Food service. Luggage stowage. Toilet. Search and rescue is something that also needs to be allowed for, so don’t be surprised if there is a P-8 or something of its ilk moving along the their track.

C-130 more common - as it's also used as the "stager" - takes maintenance teams, spare crew, luggage etc.

Toilet is in the form of a "p*ss bag" or nappy. No hot dinners on a fighter - typical meal is sandwiches cut into soldiers. It's a strange experience eating without oxygen (hence the small bite sizes).

 

[Daver6]

About 14 years ago I was talking to a US F-16 pilot about this topic. He was in Darwin with his aircraft. According to him they flew across from the US in a group and just sat off the tanker. They would just constantly be taking turns to top-up. Ie, not leap frogging ahead to the next tanker.

 

[jb747]

Would the F22 supercruise (cruise above Mach 1) between tankers to reduce flight time if that is an overall benefit, or remain below Mach 1 to be fuel efficient - assuming subsonic is always more fuel efficient or at least Drag is horrendous around the transonic (mach 1)

No. They will stay together, especially if there's only one fighter. If there is to be a tanker replacement, it would probably just hold in front of their track and the old tanker would drop them off at the new.

Toilet is in the form of a "p*ss bag" or nappy. No hot dinners on a fighter - typical meal is sandwiches cut into soldiers. It's a strange experience eating without oxygen (hence the small bite sizes).

Whilst the cabin of an airliner is pressurised to a maximum of about 8,000', fighters are generally only pressurised to around half the aircraft's altitude. So whilst Tom Cruise and his ilk can take the masks off, they are not removed for more than a few seconds in the real world. Basically the cabin is not at a survivable altitude. It's almost impossible for an airliner to totally depress extremely rapidly and survive, but a fighter only has to lose the canopy, and you have instant depressurisation.

According to him they flew across from the US in a group and just sat off the tanker. They would just constantly be taking turns to top-up. Ie, not leap frogging ahead to the next tanker.

Fighters don't necessarily cruise all that fast either. Those drop tanks, whether full or empty, increase the form drag quite dramatically. So, even machines that might top out (for a few moments) at mach 2, most likely cruise slower than the average airliner. I recall overtaking a gaggle of F15s and their KC10 on one of the tracks between the mainland and Hawaii. We were probably doing around .84, and they were slower and lower.

 

[justinbrett]

About 14 years ago I was talking to a US F-16 pilot about this topic. He was in Darwin with his aircraft. According to him they flew across from the US in a group and just sat off the tanker. They would just constantly be taking turns to top-up. Ie, not leap frogging ahead to the next tanker.

Can be done both ways. Tanker planning is a complex topic far beyond the scope of AFF.

Leapfrogging tankers is a lot more flexible, but requires a lot more planning. The tankers prefer leapfrogging so they can stay based in one location.

Whilst the cabin of an airliner is pressurised to a maximum of about 8,000', fighters are generally only pressurised to around half the aircraft's altitude. So whilst Tom Cruise and his ilk can take the masks off, they are not removed for more than a few seconds in the real world. Basically the cabin is not at a survivable altitude. It's almost impossible for an airliner to totally depress extremely rapidly and survive, but a fighter only has to lose the canopy, and you have instant depressurisation.

Yep, that was the point I was making. I have had the pleasure of eating a sandwich in the back seat of a hornet. When having to make a choice between breathing and eating, I wasn't very hungry after a few bites.

 

[Daver6]

Speaking of tanking. At the same time I was also talking to some guys who worked on the AC-130 gunships. According to them when they needed to tank both their aircraft and the tanker entered a shallow dive. Apparently this was needed as the AC-130 couldn't maintain a fast enough speed to keep up with the tanker in level flight.

Not sure if this is true or my chain was being yanked.

 

[Quickstatus]

Some pretty obvious ones. Toilet. Sleep. Toilet. Food

O2?

 

[justinbrett]

O2?

Newer aircraft (inc F-35, F-22, F/A-18F, EA-18Gs) generate their own oxygen using OBOGS

Classic hornets carried LOX (Liquid Oxygen) but that would last multiple sorties. I don't have the numbers for you but quite long transits could be done on a single tank. Not many fighters using LOX now (none in RAAF). You also use a lot less Oxygen twiddling your thumbs in a transit vs doing a BFM mission (dog fighting)

 

[serfty]

OBOGS

Had to search... fascinating!

On-Board Oxygen Generating System (OBOGS) | Defence Research and Development Organisation - DRDO, Ministry of Defence, Government of India

On-Board Oxygen Generating System (OBOGS) centric Life Support System to provide enhanced physiology protection to aircrew of high altitude and high speed fighter aircrafts. OBOGS replaces Liquid Oxygen System (LOX) by utilizing bleed air from the aircraft engine and separating its components...

www.drdo.gov.in