The great big "ask an airline pilot" thread!

smurfjed

The concept of flying with Vertical Speed at such a high altitude is quite alarming, I wonder who taught him about high altitude aerodynamics.

Lockheed

What would happen if a jetstream pushed a normal subsonic aircraft past the sound barrier? Would there be damage?

View Profile

Nothing wrong with using VS at high altitude if you are paying attention and watching your speed.
I find VNAV can struggle sometimes to maintain a positive rate of climb as it sometimes starts descending unnecessarily to maintain its assigned speed.

Setting a few hundred feet per min keeps it climbing to the FL required.

ProfessorPlum

View Profile wrote: »

Nothing wrong with using VS at high altitude if you are paying attention and watching your speed.
I find VNAV can struggle sometimes to maintain a positive rate of climb as it sometimes starts descending unnecessarily to maintain its assigned speed.

Setting a few hundred feet per min keeps it climbing to the FL required.

Only if you are absolutely paying attention, and even then I wouldn't use it except perhaps to capture an altitude smoothing and only then if I'm absolutely certain that the aircraft has plenty of energy! This guy was climbing in V/S as a norm. That's going to get you into trouble some day.

smurfjed

What would happen if a jetstream pushed a normal subsonic aircraft past the sound barrier?

the speed of sound is relative to the air around you, not your ground speed, so the jet stream won't push an aircraft past the local speed of sound.

Irish Steve

smurfjed wrote: »

The concept of flying with Vertical Speed at such a high altitude is quite alarming, I wonder who taught him about high altitude aerodynamics.

As a private pilot, I suspect that no one did, even with the TR on the jet, given the route that he took to getting it, his FAA licence was issued on the basis of his UK PPL, which if it was anything like the UK PPL that I did many years ago, didn't touch anything related to operations above about 6000 Ft, on the basis that even then, the UK airspace above 6000 Ft was pretty much controlled airspace, and not readily accessible or available to PPL holders.

There is no mention of which system he did an Instrument rating in, and it's not mentioned at all in the report, which would be unusual, but to be operating at those levels in the UK, he would have to had done an IR somewhere, but even then, there's no requirement in the IR to have any high level training, it would be part of the CPL/ATPL exams, and from memory, they were not required for an IR on either side of the pond.

So, the only scenario for that sort of training would have been during the TR for the type, and depending on the instructor and the place where the TR was done, your guess is as good as mine as to the level of "peripheral" training and checking that was carried out.

The other factor that is relevant is that this was a single pilot operation, which is valid for the type, but is a significant factor in increasing the workload that the pilot is faced with. In hindsight, looking away from the flight instruments at a transition point in the flight was unhelpful, as it provided the distraction that allowed the upset to develop.

That said, let him that is without sin...................

Another aspect was the significant departures in vertical speed once a measure of control had been re established, plus and minus 23/2400 fpm is a significant variation in VS, and it continued for a minute and a half before the automation was re engaged, which suggests to me that the automation did most of the flying at high levels, and hand flying in thin air came as an uncomfortable shock.

I suspect that once the aircraft was repaired, the owner will have been doing more hand flying that he had been used to. It would certainly have been prudent.

ProfessorPlum

Good point about the IR - did he have one? The report stated he could only regain control when he was in VMC, and didn't understand what the instruments were telling him. He's a brave man flying around without an IR.

On the vertical speed variations after control was regained, to be fair, very gentle control inputs or a couple of degrees of pitch will get you that at very high altitude, and I'm guessing he would have been fairly twitchy at that point!

smurfjed

I have colleagues who had to obtain a high altitude endorsement prior to getting a jet type rating in the USA. So i would assume that he had done one, however, it doesn't appear to have been that beneficial.

My issue with the report is that he appears to have done all his flights at FL430, regardless of the length of the sector, so I'm not actual sure that he was familiar with his aircrafts capabilities as very few aircraft will get to their ceiling immediately after a heavy weight takeoff.

Irish Steve

ProfessorPlum wrote: »

Good point about the IR - did he have one? The report stated he could only regain control when he was in VMC, and didn't understand what the instruments were telling him. He's a brave man flying around without an IR.

On the vertical speed variations after control was regained, to be fair, very gentle control inputs or a couple of degrees of pitch will get you that at very high altitude, and I'm guessing he would have been fairly twitchy at that point!

Don't think he'd have been legal in higher flight levels without an IR, but yes, there are some interesting aspects of the flight in terms of recovery and stability that raise some challenging questions about the regular use of automation to operate at high levels. I know the first time I got my hands on a simulator and did some high level flying, (as a lowly PPL holder at the time) getting the thing (BAC 1-11) to stabilise at those levels while hand flying was "interesting" and darned hard work, breathing on the controls rather than moving the controls would have been a more appropriate description, and I was used to a PA39 twin, which was pretty sensitive in pitch.

smurfjed wrote:

I have colleagues who had to obtain a high altitude endorsement prior to getting a jet type rating in the USA. So i would assume that he had done one, however, it doesn't appear to have been that beneficial.
My issue with the report is that he appears to have done all his flights at FL430, regardless of the length of the sector, so I'm not actual sure that he was familiar with his aircrafts capabilities as very few aircraft will get to their ceiling immediately after a heavy weight takeoff.

Also a valid point, the utilisation wasn't massive, 2 Hrs per week on average, and by the look of the information in the report, a couple of flights per month to somewhere like Palma, an average of 5 hours a month over the previous 90 days, ( and similar since initial type rating in 2006, an average of 100 Hrs per year) so I suppose it's possible that he wasn't fully aware of the potential (and limitations) of the flight envelope of the aircraft. Re going to that height, he was probably light enough to get up there, he was only going two thirds of the range of the aircraft, and with only one pax, should have been reasonably light.

There's still plenty of pucker factors about the flight though. That said, the issue with the AOA meant that he was denied important operational information about the conduct of the flight, and most significantly, he didn't get warnings of the situation in a timely manner, and that meant a subtle gotcha that crept up on him with no real warning, and using VS meant that he was denying himself a protection that should have been there.


At some stage it will be interesting to see how Cessna address the issues that this report has raised, as it was primarily caused by a single failure with no alternative backup system to provide a check of the primary source.

pclancy

Can any 737 drivers tell me do you use standard speeds to climb at? Like V2+10 up to ?, 250kts to 10,000, then what, 300 or so up to altitude? Or does it always vary based on weight/temps etc?

bkehoe

The most economical climb speed is dynamically calculated by the Fmc based upon the weight and winds entered during preflight. So in general it will fly slower so as to climb at a higher rate if a tailwind is anticipated in order to benefit from it.

250 below 10,000 ft is a standard limitation which can be lifted by ATC.

The acceleration to 250kts is typically only commenced once we're at least 3000ft above the aerodrome and the flaps are up (standard noise abatement 1 or 2 used by all airlines and types). Some airports are special cases, and in other cases pilots may use their discretion to climb at a lower speed; for example there's no point accelerating in the wrong direction, or in some airports it's beneficial to gain altitude quicker so as to get direct routings from ATC especially if there's high terrain around.

It's also worth pointing out that at some point in the climb the FMC will transition to command a Mach number. So the climb may be at 275/.76 which means that once the Mach rises to .76 as the aircraft is climbing at 275, the .76 will become the climb speed. This is what's meant if you ever hear ATC give an aircraft a speed limit on transition, usually in the descent.

knockon

Tomorrow mornings forecast for gusts up to 130kmh in Dublin Airport possible - any implications for outbound traffic at midday? Just looking at the possibility of delays from DUB - CDG with City Jet

lord lucan

Not sure if we've any sky handling ramp guys on here but I noticed an EIR ATR being hauled from the gate rather than being pushed back earlier, never seen it before and was wondering if this was a common occurrence?

martinsvi

knockon wrote: »

Tomorrow mornings forecast for gusts up to 130kmh in Dublin Airport possible - any implications for outbound traffic at midday? Just looking at the possibility of delays from DUB - CDG with City Jet

if the plane won't be delayed/diverted inbound, 45kt southwest gusts (Dublin TAF) should not prevent avro from take-off, it wont get much worse than it is now, and so far everything's pretty much under control, except EI Lyon flight going around

billie1b

lord lucan wrote: »

Not sure if we've any sky handling ramp guys on here but I noticed an EIR ATR being hauled from the gate rather than being pushed back earlier, never seen it before and was wondering if this was a common occurrence?

Not Sky Handling, but with our company we park them nose into the wind on stand if the wind is bad enough, most times it stops the a/c from being lifted and turned on stand, also safer for the pax to board that way when the wind is nasty, we usually pull them from stand then to stop the jetblast on the terminal.

lord lucan

billie1b wrote: »

Not Sky Handling, but with our company we park them nose into the wind on stand if the wind is bad enough, most times it stops the a/c from being lifted and turned on stand, also safer for the pax to board that way when the wind is nasty, we usually pull them from stand then to stop the jetblast on the terminal.

That makes perfect sense,thanks. Crappy phone pic from a distance to illustrate what i was talking about.

basill

All commercial aircraft have wind limits, not only for landing and taking off but also for things such as cargo/pax door opening. There have been a number of instances where aircraft have jumped off their chocks and weather cocked. Where possible aircraft will be parked into wind and the lee side used for door opening if it's below limits. Delays can occur in offloading pax and bags when out of limits as well as servicing aircraft eg:fuel, toilet, catering etc.

postitnote

I would imagine it's prudent to be upwind when servicing the toilet.

MIDLANDSMAN

Hi. I have an interest in all things aviation and enjoy this thread a lot. However, I have several questions which I have often wondered about when ever I have been on a flight, so I decided to hit you with them all at once. They are a mix of simple and possibly stupid questions but I would love if someone could take the time and maybe answer them. Apologies if it seems like a long list but it might keep someone busy on the forecasted cold weekend. Thanks.

1-Is there a speed limit when a plane is taxing on a runway? Some times, especially on long taxis, some planes seem to travel faster than other on the ground.

1a-If there is a speed limit, who monitors it? ATC? How would ATC know if they broke the speed limit?

2-This may be a silly question but how does a plane actually turn when taxing? Does the pilot apply brakes to one set of gear only and make the plane turn that way or is there a wheel or tiller to turn the front landing gear or can you vary the power to each engine depending on the direction you want to go?

3-How difficult is it to find your way to the allocated gate after landing especially at night, in a large airport with a maze of lights, taxiways, runways, aprons, etc. Are you guided each step by ground control or do you follow charts and hope you’re on the right track. From a passengers point of view, it seems at night we could easily end up in the grass or a field somewhere or maybe the view from the cockpit is clearer!

4-I was recently on a flight from Madrid to Dublin where a Ryanair and an Aer Lingus flight both bound for Dublin left within a few minutes of each other. It got me thinking, if over the Bay of Biscay or out of controlled airspace for example, a plane following another slightly slower plane on the same route, wanted to pass it out (or over take), is it allowed to over take? Or do they have to stay in the order that they are in even if it means the following plane has to fly slower. If they can pass, do they pass above, below, to the side, etc?

5-Sometimes, I have been on a flight and after arriving at the gate, seat belt sign is switched off and the scramble to get to your the bags and get off the plane begins, I have heard a noise coming from below the cabin. I’m usually around row 20 or so. I’m assuming it is the baggage handlers opening doors or something to do with hydraulics. The best description of the noise is that of a fellow with a hand saw trying to cut a plank of timber. Any ideas what it could be?

6-I heard that pilots generally work an early or afternoon roster. Would that mean that all pilots in the morning roster would arrive in at 5am or so to find out where they are flying to that morning? Even though they might know their roster for several days, would they know in advance where they are actually going to be flying to for the following days? Could they arrive in for 5am and discover that they are not due to leave until 8 or 9am for example and have to hang around waiting?

7-If a plane was at 35,000 feet or crusing altitude and directly over an airport and an emergency occurred (medical or etc). Could they descend rapidly (like a spiral) to get to that airport or in other words what would the closest airport be that a plane can land at, in an emergency from that altitude and speed?

8-On landing, planes use brakes, spoilers and reverse thrust to stop. Am I correct? Are these three systems equally effective at stopping or could a place stop if 1 wasn’t working?

9-Also, I’ve noticed that planes rapidly decelerate and stop when landing and often there is ample runway left. Why the need to stop to quickly? Why do they not stop more slowly, use the full length of the runway and save the brakes? Maybe it is to vacate the runaway ASAP for the next plane landing and save time for the turn around but I’m just guessing this.

smurfjed

1: Yes, limited by either the airplane or company limitations

2: Ground radar in certain airports but they don't know what you airline limits are.... so the real answer is probably no one

3: Bloody difficult for strange airports, thats why you see aircraft taxiing slowly...

4: Both would be controlled even in that area..... if in VFR conditions and airspace, then standard rules of the air would apply.

5: I think that you are talking about the A320 hydraulic transfer system..... it doest apply to other aircraft

6: Depends on the airline, but considering that pilots are controlled by duty time, its not prudent to have them sitting around.

7: Yes, but it would happen...... gentle easy approaches make more sense.

8: No they are not the same in capability, especially depending on the runway condition..... strangely enough the spoilers are generally the worst one to lose..

9: General airline rule to be quick, or airport runway minimum occupancy time constraints....

Hope that i got some right

IRLConor

MIDLANDSMAN wrote: »

8-On landing, planes use brakes, spoilers and reverse thrust to stop. Am I correct? Are these three systems equally effective at stopping or could a place stop if 1 wasn’t working?

smurfjed wrote: »

8: No they are not the same in capability, especially depending on the runway condition..... strangely enough the spoilers are generally the worst one to lose..

In addition to smurfjed's answer there's an interesting thread about brakes, spoilers and reverse thrust here: http://www.boards.ie/vbulletin/showthread.php?t=2057320512

Aircraft Freak

It's probably a question that has been asked before, I have flights booked for Majorca in May, the flight leaves at 18:30, and the return flight is at 22:30 (Spanish time) does the pilots day start with the flight @ 18:30? or has he done this flight twice in one day?

L1011

Aircraft Freak wrote: »

It's probably a question that has been asked before, I have flights booked for Majorca in May, the flight leaves at 18:30, and the return flight is at 22:30 (Spanish time) does the pilots day start with the flight @ 18:30? or has he done this flight twice in one day?

Which airline? Rota patterns and also aircraft use vary quite a bit between them and you'll likely get a more accurate answer with the airline given.

Aircraft Freak

L1011 wrote: »

Which airline? Rota patterns and also aircraft use vary quite a bit between them and you'll likely get a more accurate answer with the airline given.

EI, hopefully DVM.

Jack1985

Pilots at EI work a 5:3 roster now, usually consisting of doubles for the 5 days - However, of course some sectors would inhibit that (dependent on duty hour limits). Speaking for CC, PMI would be a single duty that day (DUB-PMI-DUB).

Tenger

Aircraft Freak wrote: »

It's probably a question that has been asked before, I have flights booked for Majorca in May, the flight leaves at 18:30, and the return flight is at 22:30 (Spanish time) does the pilots day start with the flight @ 18:30? or has he done this flight twice in one day?

Good bet that it is the same flight crew on both sectors.

Check-in 1730, DUB-PMI 1830-2040 local, less than 60 minutes on the ground. PMI-DUB STD is 2130, land back in DUB at approx 2340? Or something close to that anyway. Its only a 6 hr duty so could have a shorter duty preceding it.

4. Controlled airspace, usually just an overtaking manoeuvre same level. You see it quite often on flightradar24 coming in to Dublin jet passing an ATR.

Most aircraft will be at different levels so it's quite easy.

Outside of radar coverage like the Atlantic, aircraft will fly a set speed from one side to the other so ATC can take that into account. Usually they will add a few extra minutes between aircraft so they don't catch each other up. But something that will be much slower will not be allowed join the tracks and will either have to take a lower level or another routing to the side. Imagine a granny driving a Micra on the M50 at 50kmh and everything else is doing 90-100 you woulduch prefer if she didn't join the M50 and was told to use the side roads. The speed difference in general aren't huge for most aircraft and generally anything that is much slower can't usually fly that high anyway bar a few small biz jets and turboprops.

MIDLANDSMAN

Thanks to Smurfjed and all who answered my questions that I posted here. It has satisfied my curiosity and I'll start working on the next list of questions now.

faceman

Flying westbound from DUB to SFO today. Anyone know how the turbulence is looking en route given the recent frequent bad weather?

martinsvi

faceman wrote: »

Flying westbound from DUB to SFO today. Anyone know how the turbulence is looking en route given the recent frequent bad weather?

http://www.turbulenceforecast.com/atlantic_westbound_tracks.php

this an that at around FL340, doesn't look to major, enjoy your trip, I'm planning SFO myself later on this year