Ask The Pilot

[flychrisfly]

I expect it that no matter how much it shook, it wasn't inside the tunnel they were looking through. You'd be amazed at what your system can filter out. QF30 climbed at a peak rate of 100,000 fpm, which you'd think you'd notice...but none of us (in the coughpit) did.

A mach 1.49 climb in a 747?!?

 

[Boca68]

A mach 1.49 climb in a 747?!?

going to assume its a typo. maybe 10,000 fpm?

 

[jb747]

Boris, I would have thought, being the air force, you guys would have had the electronic solid state sensors for aerobatics.

I think Boris is saying that the standby would topple. The main AI in the Macchi didn't seem to have any issues, but it didn't have a standby (at least in my time, there was talk of one in a refit).

For those of a mechanical mind...the A4G AI also incorporated heading, so it was a bit like a map of the world, in which all lines would meet at the poles. Didn't topple either. There's a drawing here. It was a very cunning bit of design.
http://i98.photobucket.com/albums/l261/SpazSinbad/ABBAJABBAlinedrawNATOPSforum.gif

 

[jb747]

A mach 1.49 climb in a 747?!?

going to assume its a typo. maybe 10,000 fpm?

Ha...no, it isn't a typo. But, it's not measuring a speed either.

The cabin climbed from approximately 5,000' to 29,000' in 13 seconds. So, the cabin rate of climb was in excess of 100,000 fpm. But that's just the rate that the air was going away...nobody was going that fast (that I know of).

 

[Boris spatsky]

I think Boris is saying that the standby would topple.]

Yes, the standby would topple. Pretty annoying because the instructor generally turned the main AI off early. Once the standby toppled it was pretty useless, so you essentially had to recover partial panel from memory (that is, without an AI).

 

[por930]

Yes, the standby would topple. Pretty annoying because the instructor generally turned the main AI off early. Once the standby toppled it was pretty useless, so you essentially had to recover partial panel from memory (that is, without an AI).

Yes, JB and Boris, my mistake. When I re-read your post Boris, you did say the main was turned off earlier. Your instructor probably knew the standby AI would topple and be of no use.

 

[straitman]

Just to add to a few of the comments here.

One RAAF student i had was already a 2500 hr commercial pilot. Needless to say he was pretty good at most sequences including instrument flying. Aerobatics brought him down to earth and limited panel IF nearly caused him to fail. With the IF it was his experience that caused the problem as he had major trouble learning the extra technique required for flying without the attitude indicator and main compass.

I've never heard of anyone becoming sick in the sim...other than by their performance.

Many newer helicopters have some pretty good simulators these days. Go back about 20 years though and the helicopter simulators whilst realistic also had some pretty dramatic limitations. It was not uncommon for pilots to get sick in the S76 and Blackhawk simulators then. I would feel nauseous after about 30 min in the S76 but could go for about 5 hours after a couple of ginger tablets. Outside the sim I have felt ill once in a PC9 after a spin and once in my early Macchi days.

I would have thought, being the air force, you guys would have had the electronic solid state sensors for aerobatics.

In the early days of the CT4 (around 1976-77) it had a standard light aircraft AI so had all the limitations you mention por930.

Also prior to the PC9 that Boris talked about the Macchi had the same system for IF training with the student under the hood in the back seat. It was discovered whilst we were on course that this could cause a problem with the canopy coming unlatched in flight and this actually lead to a fatal accident at Pearce in 1970. (Aircraft were quickly modified and procedures changed to ensure that it could not be repeated)

 

[Boca68]

Ha...no, it isn't a typo. But, it's not measuring a speed either.

The cabin climbed from approximately 5,000' to 29,000' in 13 seconds. So, the cabin rate of climb was in excess of 100,000 fpm. But that's just the rate that the air was going away...nobody was going that fast (that I know of).

So, its more like a 'burst" speed, (for want of a better word). i.e. can be measured over a few seconds, but not a sustained rate of climb?

is that a delayed instrument repsonse? Or other factors in play?

 

[jb747]

So, its more like a 'burst" speed, (for want of a better word). i.e. can be measured over a few seconds, but not a sustained rate of climb?

Is that a delayed instrument repsonse? Or other factors in play?

I don't think you understand. The cabin pressure was at 5,000'. Thirteen seconds later it was at 29,000'. That wasn't a gauge reading, but, rather the actual pressure. In that short interval, all of the air had rushed out of the hole. It is described as a rate of climb, but you could measure it as a rate of change of pressure. Pilots think in terms of altitude, so it's a logical way to display it. I have no idea what the system actually displayed though...it wasn't important at the time. It's just a number that quite amazed me when looking at the data later, as it was far larger than I imagined.

 

[mjt57]

Go back about 20 years though and the helicopter simulators whilst realistic also had some pretty dramatic limitations. It was not uncommon for pilots to get sick in the S76 and Blackhawk simulators then.

When we were in the Air Cadets (26 flight) I remember one kid spewing up in the Link Trainer that we had. Never quite smelled the same after that...

 

[jb747]

Also prior to the PC9 that Boris talked about the Macchi had the same system for IF training with the student under the hood in the back seat. It was discovered whilst we were on course that this could cause a problem with the canopy coming unlatched in flight and this actually lead to a fatal accident at Pearce in 1970. (Aircraft were quickly modified and procedures changed to ensure that it could not be repeated)

This was on your course?

In the fatal accident, it was thought that perhaps the student, instead of pulling open the hood, had actually opened the canopy. I know it's a totally different action, but you can get very tired on one of those flights. The Macchi canopy was hinged on the side, so it opened, and then the air loads ripped it off. Sadly it hit the instructor in the front seat, and the student wasn't able to get control in time to avoid the ground. (I think that's the gist of it). So, from that point onwards, opening the hood at the end of an IF sortie was banned...you were under it until the end of the landing roll.

As it turned out though, the student may have been unfairly blamed. In 1980, a Macchi crew (on my course) got a canopy warning light. This was a GF sortie, with the student in the front seat. The instructor took over, and the student lowered his seat as far as it would go. Whilst it looked normal, the RAAF history with this was bad, so the instructor decided to jettison the canopy. At that exact second, the canopy opened. So, left hand side unlocked and open, right hand side hinges explosively cut...but now the canopy was still attached by a counterbalance in the centre. That should have been cut, but as it turned out, it only happened if the canopy was closed. Now they are in a real predicament, with the canopy flailing in the breeze. Instructor fed in full right rudder (which got the canopy as far away as possible) and told the student to eject. He followed seconds later.

The student was a tall lad, and having the seat all the way down, and his feet off the rudder pedals meant that his legs were raised a few inches above the seat squab. An ejection is an incredibly violent event. You'll almost certainly be hurt, perhaps seriously, but it hopefully beats dying. In this case the seat had that few inches of travel before it picked up his legs..which it promptly broke just above the knees. He recovered, and was put back on course about 6 months later.

In the subsequent investigation, it was discovered that the right combination of adjustments and shims in the canopy locking mechanism could set up a system which would literally open itself. An aircraft was adjusted to the absolute maximum allowed. Parked in the hot WA sun for a few hours, and the canopy suddenly unlocked. Air and dynamic loads could make it happen earlier.

So, firstly maintenance changed the way the canopies were adjusted. Secondly, a procedure was added to the checklist which attempted to deal with a canopy warning. Basically you had to very carefully identify which direction to move the handle to open or close the canopy. Don't get it wrong. Then unlock the handle, and pull to the lock and hold it there. As you needed two hands to fly the aircraft there were some issues. It happened to me when I was in the back seat at Nowra (just off for a ride I think), and I could barely move my hand when we landed as I'd been holding it so tightly.

 

[por930]

Very interesting JB. made me go and look at more info on it. Being military, not too much, but this article gives readers a visual of the a/c and the canopy in question. ADF-Serials Image Gallery :: THE LOSS OF MACCHI A7-039.

My early days were in a Victa Airtourer 115, which had a sliding canopy we usually left open until take off to achieve some ventilation.

 

[Stevo.1702]

Also prior to the PC9 that Boris talked about the Macchi had the same system for IF training with the student under the hood in the back seat.

Soon to be a thing of the past. Unlike the PC-9, the PC-21 isn't designed to have a bag. All IF flights will have students in the front seat. IMC training will be heavily simulator based.

 

[flyingfan]

Reading about a QF medical emergency descent in Oman and it's reported that a passenger witnessed "a very fast descent." What sort of considerations come into play for a normal passenger aircraft commencing from top of descent - does ATC work on bringing the aircraft to a certain speed and altitude to enable a further final descent down to the airport approach? Wikipedia mentions a rule of three, is this correct for a general principle of descending gently enough for passenger comfort reasons? I guess this is all programmed into the flight computer and there usually doesn't need to be a changed.

Then in a medical or otherwise emergency, what's the minimum time it would take for a descent say from cruising? Overweight landing from fuel would be a factor I expect (and I believe jb747 has mentioned balancing the level of risk between a quick landing and the issue at hand) - what else comes into it?

Extra question... I read about a revised descent process which would apparently result in a smoother continual glide from TOD and also be more fuel efficient - is this being implemented?

 

[jb747]

Reading about a QF medical emergency descent in Oman and it's reported that a passenger witnessed "a very fast descent." What sort of considerations come into play for a normal passenger aircraft commencing from top of descent - does ATC work on bringing the aircraft to a certain speed and altitude to enable a further final descent down to the airport approach?

ATC just clear you for a descent to a level. In this instance they would have declared an emergency, so they'll get the other aircraft out of the way, instead of making you fit in as is usually done. It's up to you to calculate the balance of height, speed, and distance to run. Full speed brake, and about mach .85, converting to about 320 knots would give an appreciably steeper descent than most passengers would ever have seen, and would knock about 50% off the normal distance.

Wikipedia mentions a rule of three, is this correct for a general principle of descending gently enough for passenger comfort reasons? I guess this is all programmed into the flight computer and there usually doesn't need to be a changed.

There is no 'rule of 3' as such. It's just that a gliding airliner will travel approximately 3 miles for every thousand feet of height lost. It's closer to 3.5. The FMC is able to calculate the descent path using whatever speeds we program into it. It assumes idle power, and no speed brake. Use of large amounts of speed brake will make the descent steeper, and the rumble/vibration will upset many. Beyond that though, descents are at the best rate we can get clean and at idle. Speed brake will be used to correct speed excursions, or altitude errors.

Then in a medical or otherwise emergency, what's the minimum time it would take for a descent say from cruising? Overweight landing from fuel would be a factor I expect (and I believe jb747 has mentioned balancing the level of risk between a quick landing and the issue at hand) - what else comes into it?

Using the emergency descent profile, it would take 7 minutes and 51 nm from 40,000 to get to 1,500'. You'd need to slow down, and fly finals, but I guess it could be done in about 10 minutes to wheels stop.

Extra question... I read about a revised descent process which would apparently result in a smoother continual glide from TOD and also be more fuel efficient - is this being implemented?

We always fly the most fuel efficient descent possible. Sadly ATC have this nasty habit of imposing altitude steps and speed constraints...most likely because we aren't the only aircraft in the air. Occasionally all airports manage a descent without any constraints, but they are very rare.

 

[jb747]

My early days were in a Victa Airtourer 115, which had a sliding canopy we usually left open until take off to achieve some ventilation.

We taxied the CT4, Macchi and A-4/TA-4 with the canopy slightly open. When it really got hot though, the A-4 had decent air con, so we'd close them.

 

[straitman]

This was on your course?

In the fatal accident, it was thought that perhaps the student, instead of pulling open the hood, had actually opened the canopy. I know it's a totally different action, but you can get very tired on one of those flights. The Macchi canopy was hinged on the side, so it opened, and then the air loads ripped it off. Sadly it hit the instructor in the front seat, and the student wasn't able to get control in time to avoid the ground. (I think that's the gist of it). So, from that point onwards, opening the hood at the end of an IF sortie was banned...you were under it until the end of the landing roll.

As it turned out though, the student may have been unfairly blamed. In 1980, a Macchi crew (on my course) got a canopy warning light. This was a GF sortie, with the student in the front seat. The instructor took over, and the student lowered his seat as far as it would go. Whilst it looked normal, the RAAF history with this was bad, so the instructor decided to jettison the canopy. At that exact second, the canopy opened. So, left hand side unlocked and open, right hand side hinges explosively cut...but now the canopy was still attached by a counterbalance in the centre. That should have been cut, but as it turned out, it only happened if the canopy was closed. Now they are in a real predicament, with the canopy flailing in the breeze. Instructor fed in full right rudder (which got the canopy as far away as possible) and told the student to eject. He followed seconds later.

The student was a tall lad, and having the seat all the way down, and his feet off the rudder pedals meant that his legs were raised a few inches above the seat squab. An ejection is an incredibly violent event. You'll almost certainly be hurt, perhaps seriously, but it hopefully beats dying. In this case the seat had that few inches of travel before it picked up his legs..which it promptly broke just above the knees. He recovered, and was put back on course about 6 months later.

In the subsequent investigation, it was discovered that the right combination of adjustments and shims in the canopy locking mechanism could set up a system which would literally open itself. An aircraft was adjusted to the absolute maximum allowed. Parked in the hot WA sun for a few hours, and the canopy suddenly unlocked. Air and dynamic loads could make it happen earlier.

So, firstly maintenance changed the way the canopies were adjusted. Secondly, a procedure was added to the checklist which attempted to deal with a canopy warning. Basically you had to very carefully identify which direction to move the handle to open or close the canopy. Don't get it wrong. Then unlock the handle, and pull to the lock and hold it there. As you needed two hands to fly the aircraft there were some issues. It happened to me when I was in the back seat at Nowra (just off for a ride I think), and I could barely move my hand when we landed as I'd been holding it so tightly.

Very interesting JB. made me go and look at more info on it. Being military, not too much, but this article gives readers a visual of the a/c and the canopy in question. ADF-Serials Image Gallery :: THE LOSS OF MACCHI A7-039.

This accident occurred on 11 August 1970 at Gin Gin and the student was from No 76 pilots course. I was on No 77 course and we had just arrived at Pearce. The information in the link provided by por930 varies a little from what was explained to us at the time.

The theory was that the student was pulling back the hood as the aircraft pitched and that his arm/hand hit down hard on the canopy lever which caused the canopy to unlock. At that time the latch locked into a V shape notch and it was discovered that on some aircraft a hard enough impact could release the catch. The design was changed to the latch having a U shape and this overcame the problem. As a further precaution procedures were changed so that the hood remained closed until after landing.

Later that year on the 19[SUP]th[/SUP] November a member of our course (Rob Ellis) died after ejecting from his Macchi during his first night solo sortie when his aircraft hit trees. He was outside the ejection parameters for the aircraft and ejection seat.

For a bunch of 18,19 and 20 years olds this was all a pretty tough time and certainly had a long term effects on how we looked at things going forward.

In early 1971 another from our course (Roger Harrison) was in the back seat of a Macchi on a test flight (flown by Ron McGrath) when the canopy detached from the hinge side. In circumstances similar to that described by jb747 the canopy flailed around but then departed the aircraft. Fortunately the crew did not attempt to eject as their seats had been damaged by the impact from the canopy.

 

[straitman]

We taxied the CT4, Macchi and A-4/TA-4 with the canopy slightly open. When it really got hot though, the A-4 had decent air con, so we'd close them.

I actually had to call the aircraft ahead of me one day as he started his takeoff roll with the canopy on the latch rather than locked. It was a student solo from my course also. Ultimately that person failed the course.

 

[Melburnian1]

'The Sydney Morning Herald' has just posted an article on its website 'Flying tired: airline pilots on tough rosters battle fatigue.' Presumably it will be in the Saturday print edition as well.

If I had to stay in hotel rooms as often as pilots do, after the novelty (first six months) had worn off, I too might find noisy other hotel guests, talkative cleaners (room attendants) and perhaps even occasionally not very good blackout curtains to be tedious.

I've never seen any widely publicised research but one does wonder in all these shift work occupations where numerous nights are spent away from home (some pilots, train drivers, seafarers, coach and heavy vehicle drivers and so on) whether at least to a minor extent it adversely affects life expectancy, particularly if the shifts are rotating and perhaps magnified if one is passing through various different time zones.

 

[por930]

'The Sydney Morning Herald' has just posted an article on its website 'Flying tired: airline pilots on tough rosters battle fatigue.' Presumably it will be in the Saturday print edition as well.

Yeah, reads pretty grim. Only their professionalism keeps them going. I have often thought, especially for the international pilots, there should be a universal set of duty/flight hours, roster rules. The "rested" flight crew leaves one country only to present them selves at another countries airport after a long flight of 8 -15 hours, by now considerably tired, into peak hour air traffic, though in some bad weather, a bit of holding...then ready for the commute to the hotel, to encounter noisy cleaning staff. So, while the EK pilot flies with their company policy, they land in a different countries mandated requirements....Sort of pass on the problem?...The link to Melburnian1 article is Flying tired: airline pilots on tough rosters battle fatigue

JB, Boris etc, what do you see as the 'best' outcome if you could mandate a set of conditions. There have been some accidents of recent times where strange decisions were made by trained and capable pilots though several factors, probably fatigue among them.
Domestic pilots have their own issues with the early start/ late night finish domestic flights, which I caught many many times a month to save on hotel expenses. These pilots seem to return with their flight as another leg in some instances.