Ask The Pilot

[datal1]

Hey jb747, if I recall a past post of yours you were flying qf9 from Mel to sin on the 31st. What was the reason for the 50 min departure delay? We were told it was something to do with engineers giving the ok to board but that's all.

 

[jb747]

Hey jb747, if I recall a past post of yours you were flying qf9 from Mel to sin on the 31st. What was the reason for the 50 min departure delay? We were told it was something to do with engineers giving the ok to board but that's all.

Other way around. I flew the 10 out of Singapore on the 31st.

 

[schomers87]

JB- have you read Richard De Crespigny's QF32 at all? Would have thought it would have been a very interesting text for any one in the industry or enthusiast?

 

[jb747]

JB- have you read Richard De Crespigny's QF32 at all? Would have thought it would have been a very interesting text for any one in the industry or enthusiast?

I have a digital copy of it. I've read some, but not all of it. I'm not the target market. If I want to know something about that day, I'll just ask one of them.

 

[schomers87]

Fair enough. I've included it in my summer reading. For a non-expert it is a very interesting read.

 

[AVC]

Re: Now Boarding ... Chicken or Beef?

Finding reverse gear to back out of the gate might be a bit tricky, too.

Would reverse thrust and a bootful of Jet A1 work in this scenario?

I read a book one time (which was written by a guy who was both a pilot and lawyer) which had this very scenario. Except the plane wasn't being stolen per se, but they were doing a runner and basicallt "pushed themselves back".

The obvious dangers are slamming the tail into another aircraft/vehicle/building, and blowing loose item all over, or into, the terminal building.

 

[wafliron]

Re: Now Boarding ... Chicken or Beef?

A question, perhaps a little different to the usual in this thread...

I'm booked in to do the "Qantas Flight Simulator Experience" (https://store.qantas.com/Catalogue.a2?Page=ViewProduct&ProductskuId=158140) on Thursday morning - can't wait. Can any of the pilots in this thread suggest scenarios which someone - i.e. me - who is interested in aviation, has a basic understanding of the physics of flight / control surfaces / coughpit instruments, but is not a pilot, would find most interesting?

Already on the list, time permitting, are:
- take-off and landing (duh!)
- aborted take-off
- watching the plane auto-land in difficult conditions
- a serious emergency situation, mainly to see what happens in the coughpit (warnings, FMC output, etc)
- stall / stall recovery

Appreciate any input - thanks! And also a good opportunity to say thank-you to all who have contributed to this wonderful thread, I'm only about 1/4 of the way through it and am finding it is fascinating.

 

[jb747]

Re: Now Boarding ... Chicken or Beef?

I'm booked in to do the "Qantas Flight Simulator Experience" (https://store.qantas.com/Catalogue.a2?Page=ViewProduct&ProductskuId=158140) on Thursday morning - can't wait. Can any of the pilots in this thread suggest scenarios which someone - i.e. me - who is interested in aviation, has a basic understanding of the physics of flight / control surfaces / coughpit instruments, but is not a pilot, would find most interesting?

Already on the list, time permitting, are:
- take-off and landing (duh!)

Just shut your eyes....

Approach power is about 1.20 EPR. If using manual thrust, make all changes gentle (.02 or so). Bigger changes will give a strong pitch couple. And if you need more, remember that you'll have to push or pull as appropriate. It's a Boeing...even when the autothrottle is engaged, you can still override it without disengaging it.

- aborted take-off

There are many, many reasons for an abort, not just engine issues. Ask for an engine failure with severe damage at V1 minus about 5 knots. Do it at max take off weight. And for a real eye opener, ask for the same failure at 10 knots (i.e. as the power is being set).

- watching the plane auto-land in difficult conditions

We don't autoland in 'difficult' conditions per se. In some ways they're simple. Just very reduced vis...fog. It's pretty useless in gusty/nasty condtions. Ask to see a CAT III B autoland.

- a serious emergency situation, mainly to see what happens in the coughpit (warnings, FMC output, etc)

The sims aren't necessarily all that good at giving compounding emergencies. Normally the instructor will have to individually key them in.

If you want my scenario, you want a bang, autopilot disconnect, loss of 50% of roll control, door warning, loss of cabin pressure, crew and cabin oxygen warnings, anti skid, brake torque, left ADC fail, left FMC fail, all ILS fail, left CDU frozen....I'm sure that's enough to keep you happy, but I'm not sure that he can key it all in.

- stall / stall recovery

You slow down until the stall warning goes off. Then lower the nose to about 5º below the horizon, and slowly advance the power. Don't do it quickly because the thrust couple will pitch the nose back up. So, angle of attack FIRST...then the power.

 

[jb747]

Re: Now Boarding ... Chicken or Beef?

Would reverse thrust and a bootful of Jet A1 work in this scenario?

I read a book one time (which was written by a guy who was both a pilot and lawyer) which had this very scenario. Except the plane wasn't being stolen per se, but they were doing a runner and basicallt "pushed themselves back".

The obvious dangers are slamming the tail into another aircraft/vehicle/building, and blowing loose item all over, or into, the terminal building.

Most engines provide very little actual reverse thrust. Yes, I know there are some aircraft that can be backed, and also it is, on some occasions used to 'help' a tug with pushback. But, the big engines will simply cook themselves, and you'll go nowhere.

An RB211 or CF6 provides roughly 60,000 lbs of forward thrust at full power, and around 5000 lbs at idle. But, full reverse is worth only about 3000 lbs. Firstly, most of the air is actually being blasted sideways; there's very little forward component. Plus, the core, which is driving the whole thing, is still making lots of forward thrust. So, the overall effect is a lot of blast, and almost no 'reverse' thrust. In use, reverse has the effect of cancelling that core forward thrust, providing a small amount of reverse, and most importantly, of blasting water away from the wheels.

So, whilst you can probably steal an MD80 this way, to take something bigger, you'll need your own tug and driver as well.

 

[Fruitcake]

Re: Now Boarding ... Chicken or Beef?

Would reverse thrust and a bootful of Jet A1 work in this scenario?

Northwest used to be a fan of the "powerback," for DC-9s and 727s - I experienced a couple of them back in the day. My understanding is that for rear-engined aircraft it's quite practical (albeit at the expense of fuel, noise and some aspects of safety), but it's generally discouraged for wing-engined aircraft because of the risk of stirring up debris and ingesting it into the engine. Apparently AirTran still powerbacks their 717s pretty regularly.

http://www.airliners.net/photo/Northwest-Airlines/McDonnell-Douglas-DC-9-32/0975772/L/

 

[jb747]

Re: Now Boarding ... Chicken or Beef?

I'm sure FOD will be an issue no matter how high the engines are mounted...and compared to the big stuff, those DC9 engines aren't very high.

But, the image shows why is can be done. The reversers are blocking ALL of the flow, not just the fan. So, even though it will still be pretty inefficient, you don't have the non reversed core counteracting the reversers.

 

[mjt57]

Re: Now Boarding ... Chicken or Beef?

the image shows why is can be done.

I watched a similar aircraft reverse away from the gate at Fort Lauderdale, once.

I wonder how many pilots have hit the brakes when doing this...

Back to the sim (and the fellow who's doing it - I'm so jealous), when keying in scenarios, can't the simulator accept a programmed combination of conditions? QF30's incident would be an excellent one to reproduce, although, as you've said, the handling of it was fairly routine.

 

[jb747]

Re: Now Boarding ... Chicken or Beef?

Back to the sim (and the fellow who's doing it - I'm so jealous), when keying in scenarios, can't the simulator accept a programmed combination of conditions? QF30's incident would be an excellent one to reproduce, although, as you've said, the handling of it was fairly routine.

Routine. Did I say routine? Must have been drunk!

The sims are 'flight' simulators. They are not 'systems' simulators. In a systems sim, you can put in a switch sequence and because the real black boxes are all connected, you should get the actual aircraft response. They are used by engineers in designing the aircraft.

Flight sims have pre programmed responses to failures. Inputting random strings of failures will not necessarily result in same results as in the aircraft, which is why the failures are constrained. For instance, in the 380 sim, in it's original program, turning off ADR 3, and then failing the sideslip probe to ADR 1, would result in a couple of ECAMs, but most importantly the sim would revert alternate law 1, in which automatics are all still available. But, in reality, in the aircraft, the same failure sequence resulted in alternate law II, and the loss of all automatics. Quite a difference when five hours from landing.

In any event, to replicate QF30, the failures would all have to be individually selected. Some would, most likely, not be available at all.

 

[AVC]

Re: Now Boarding ... Chicken or Beef?

Yes, I know there are some aircraft that can be backed,.

The C130 of course, but that's using the ability to reverse the pitch of the props. I've seen them do "reverse parks" numerous times. Then again, finding a tug in the middle of nowhere is hard to do.

Another point on the DC-9, wouldn't hitting the brakes post reversing cause the pilot to have a bad CoG day?

 

[markis10]

Re: Now Boarding ... Chicken or Beef?

The C130 of course, but that's using the ability to reverse the pitch of the props. I've seen them do "reverse parks" numerous times. Then again, finding a tug in the middle of nowhere is hard to do.

Another point on the DC-9, wouldn't hitting the brakes post reversing cause the pilot to have a bad CoG day?

The Qlink Q400s will do similar in CNS frequently with a walker in attendance, while the bou's also did it on landing at many a strip, but that was to take the threshold taxiway exit

 

[jb747]

Re: Now Boarding ... Chicken or Beef?

Not really a party trick in a propellor driven aircraft though....

 

[wafliron]

Re: Now Boarding ... Chicken or Beef?

JB, thank-you very much for taking the time to reply - sincerely appreciated!

I will beg one more question though: apart from the items that were "on my list", do you have any suggestions of additional scenarios which you think I might find particularly interesting to "fly" (I use that term loosely!) or observe?

There are many, many reasons for an abort, not just engine issues. Ask for an engine failure with severe damage at V1 minus about 5 knots. Do it at max take off weight. And for a real eye opener, ask for the same failure at 10 knots (i.e. as the power is being set).

Thanks for the specific recommendations - I'll be sure to ask for the severe-damage-engine-failure at V1-5kts with MTOW. I think I'm going to have to ask for the same failure at 10kts, as you suggested, as your reply has me very intruiged...

We don't autoland in 'difficult' conditions per se. In some ways they're simple. Just very reduced vis...fog. It's pretty useless in gusty/nasty condtions. Ask to see a CAT III B autoland.

That's what I meant - I just articulated it poorly. Thanks for the specific recommendation - now I know the correct terminology to use!

The sims aren't necessarily all that good at giving compounding emergencies. Normally the instructor will have to individually key them in.

If you want my scenario, you want a bang, autopilot disconnect, loss of 50% of roll control, door warning, loss of cabin pressure, crew and cabin oxygen warnings, anti skid, brake torque, left ADC fail, left FMC fail, all ILS fail, left CDU frozen....I'm sure that's enough to keep you happy, but I'm not sure that he can key it all in.

Again I'm probably guilty of not being articulate enough. I didn't necessarily mean "serious" as in a series of major, compounding failures - although that would be interesting I'm sure! Even just seeing how the warning systems / FMC / plane react due to the catastrophic failure of a single system would probably be "enough" - your suggested engine failure scenario during take-off may well be enough. That said, I'll chat to the instructor and sim techs, and see what they can program without consuming too much time.

Finally, as a random aside, I just found out today that an old friend from high school was actually on your infamous QF30 flight! He has a series of quite good photos from the aftermath of the incident on Facebook.

 

[Boris spatsky]

Ask The Pilot

As for turbofan aircraft reversing, the C17 can do it - which makes me wonder how its reversers actually work, as they look pretty standard from the outside...

 

[Major]

Re: Now Boarding ... Chicken or Beef?

while the bou's also did it on landing at many a strip, but that was to take the threshold taxiway exit

Been there, done that...quite impressive

 

[SeatBackForward]

JB,

I would again like to thank you for making this thread by far the most interesting thread on AFF.

My question is that every airport and aircraft I've ever travelled in had always arrived at the gate nose in and then been pushed back when exiting. Is there any reason why it can't be pushed in so that the nose faces away from the gate? Wouldn't this make exiting the gate and taxiing both quicker and safer?