The great big "ask an airline pilot" thread!

Lustrum · 28-06-2014 09:51PM

In case anyone hasn't seen it, the NTSB have released an animation of the Asiana crash in SFO last year. Here it is https://www.youtube.com/watch?v=8MFPSfGoT1U

For those flying heavies, he only goes from flap 5 to flap 20 at 4.5Nm. Would this be considered fairly normal to make flap changes so late? In my (possibly over-cautious) mind, I'd imagine doing a VFR approach in a 777 that I'd like to be fully configured a lot earlier. Or is that being over-cautious?

The video is also a great example of how CRM shouldn't be done - ie. the guy who says "sink rate" three times without anyone replying to him! If only they had have listened....

View Profile · 29-06-2014 11:46AM

I don't fly heavies but on the 737 we would generally select the gear down and increase flap from 5 to 15 at about 4 or 5 nm. This would be the norm.

In the Asiana case he was high and trying to recover his glide path by increasing his descent rate. This can have the subsequent effect of increasing your airspeed, or not being able to decrease your airspeed. You need to decrease your airspeed in order to select more flap. it's a bit of a catch 22 situation.

CRM was piss poor in this case. Pilot monitoring should have picked up on the speed bleeding off much sooner, as should the pilot flying but he was task saturated trying to recover the profile.

Again this case shows how important it is for airline pilots to regularly hand fly the aircraft on approach or takeoff in order to maintain their quick instrument scanning skills.

Lustrum · 30-06-2014 02:51PM

I presume for a "normal" approach you'd select flap 15 at 4-5nm, so what would you guys have done in this situation, where you're too high? Would flaps and gear out have the desired affect do you think?

I guess I'm trying to understand how pressurised it is on an approach like that, that apparently basic flying skills and crm skills just disappear. Obviously it's a bit easier to say what you would do when you're sitting down thinking about it, but what advice would you give to someone to help them keep their heads when in a non-standard situation?

Jack1985 · 30-06-2014 03:22PM

Have heard as well the 737 can be a b*tch to slow down even with speedbrakes, is this true?

View Profile · 30-06-2014 05:47PM

Lustrum wrote: »

I presume for a "normal" approach you'd select flap 15 at 4-5nm, so what would you guys have done in this situation, where you're too high? Would flaps and gear out have the desired affect do you think?

I guess I'm trying to understand how pressurised it is on an approach like that, that apparently basic flying skills and crm skills just disappear. Obviously it's a bit easier to say what you would do when you're sitting down thinking about it, but what advice would you give to someone to help them keep their heads when in a non-standard situation?

Obviously you try to avoid situations like this where you get high on approach in the first place.

However sometimes (for example) ATC will shorten your approach by vectoring you in sooner so you may end up a tad high. In these instances and when closing in on around 15nm-20nm it is important to start slowing the aircraft down. This allows you to extend more flap, out to 5 or 10 with the gear still up. Speedbrake out to "flight detent" will also help slow you and increase your rate of descent (ROD).
Doing some mental calculations and keeping an eye on the glide slope needle you will get an idea if you are closing on the profile. If more is needed you can drop the gear. This again will help increase your ROD.

If this still isn't enough then slowing further to extend flap 15 and 30 should help but at this stage you are getting quite close to the runway. Maybe around 3nm and 1,000ft vertically. You need to be careful that your ROD isn't too high as you may get "sinkrate" or even "terrain" warnings.

Probably prudent to throw in the towel by now and call a go-around!

Tailwinds on approach add to this problem as does a having a higher landing weight.

And yes the 737 NG's newer wing design leads to a slippery aircraft which is harder to slow down compared to the older classics.

billie1b · 30-06-2014 08:14PM

View Profile wrote: »

And yes the 737 NG's newer wing design leads to a slippery aircraft which is harder to slow down compared to the older classics.

Can I ask, I was in the flight deck before returning from North Spain on a full flight on the 737-800 and we got talking, brakes came up in the conversation and how good they are on the 738. The Capt and f/o were saying to me that if they really needed to they could stop her in 700m (2300ft), granted you'd have pax with broken noses but they said it is definitely do-able on MLW. Is this true or were the taking the mick with me?

View Profile · 30-06-2014 10:03PM

billie1b wrote: »

Can I ask, I was in the flight deck before returning from North Spain on a full flight on the 737-800 and we got talking, brakes came up in the conversation and how good they are on the 738. The Capt and f/o were saying to me that if they really needed to they could stop her in 700m (2300ft), granted you'd have pax with broken noses but they said it is definitely do-able on MLW. Is this true or were the taking the mick with me?

Our Boeing landing distance calculation table states that 915m is achievable at 65t (max landing weight) with a flap 40 landing using maximum manual breaking in normal conditions. In reality you may stop sooner.

But like you said, it wouldnt be comfortable for the pax, you may spill your GnT.

billie1b · 30-06-2014 10:06PM

View Profile wrote: »

Our Boeing landing distance calculation table states that 915m is achievable at 65t (max landing weight) with a flap 40 landing using maximum manual breaking in normal conditions. In reality you may stop sooner.

But like you said, it wouldnt be comfortable for the pax, you may spill your GnT.

Cool, thanks for that

Jack1985 · 30-06-2014 10:39PM

you may spill your GnT.

Lol

, question as well if you for example in a swift move extend to flight detent the speedbrakes is the g-force from doing that in a quick move something you would try to avoid? I heard its gently you ease it out to flight detent to avoid any ''harsh'' feelings in the back?

View Profile · 30-06-2014 10:54PM

Jack1985 wrote: »

Lol , question as well if you for example in a swift move extend to flight detent the speedbrakes is the g-force from doing that in a quick move something you would try to avoid? I heard its gently you ease it out to flight detent to avoid any ''harsh'' feelings in the back?

Yes you should slowly extend and slowly retract the speedbrake. Again it is more comfortable for the passengers, especially at the back.

Jack1985 · 30-06-2014 11:03PM

View Profile wrote: »

Yes you should slowly extend and slowly retract the speedbrake. Again it is more comfortable for the passengers, especially at the back.

Cheers, have to say I miss handling the Boeing's actually prefer them over the Airbus just because I believe there's far more complexity and hands on involved in the 737NG compared to the 320 family - Does your own company have HUD's installed on the fleet? They look very useful in IMC conditions!

View Profile · 01-07-2014 05:45PM

Nah no HUD's so just Autoland in CAT 2/3 conditions.

smurfjed · 01-07-2014 05:57PM

This is a really neat site for aircraft information www.smartcockpit.com

adam88 · 02-07-2014 10:11AM

View Profile wrote: »

Nah no HUD's so just Autoland in CAT 2/3 conditions.

HUD????

L1011 · 02-07-2014 10:26AM

adam88 wrote: »

HUD????

Head-up display. Data displayed in the line of sight at its most basic description. Its a transparent screen between the pilots and the windscreen on the 737 as far as I know;

billie1b · 02-07-2014 11:07AM

MYOB wrote: »

Head-up display. Data displayed in the line of sight at its most basic description. Its a transparent screen between the pilots and the windscreen on the 737 as far as I know;

Correct, pretty much like a fighter jet pilot would use

adam88 · 02-07-2014 01:26PM

billie1b wrote: »

Correct, pretty much like a fighter jet pilot would use

Yes understand now. There obviously an optional extra??

billie1b · 02-07-2014 01:43PM

adam88 wrote: »

Yes understand now. There obviously an optional extra??

Yeah sure are, Air Dubai are the only ones I know of with them, not sure of any others

L1011 · 02-07-2014 02:00PM

billie1b wrote: »

Yeah sure are, Air Dubai are the only ones I know of with them, not sure of any others

I believe most of the airlines in the US with 737NGs have them; doesn't seem common in Europe though.

Tenger · 02-07-2014 02:37PM

MYOB wrote: »

Head-up display. Data displayed in the line of sight at its most basic description. Its a transparent screen between the pilots and the windscreen on the 737 as far as I know;

This pic shows the HUD in the B787.

B787 Cockpit by tearbringer, on Flickr

faceman · 05-07-2014 01:52PM

This is kinda a 'live' question!

I fly a lot and make no secret of the fact I'm a nervous passenger. I visit this forum a lot because it's a great way of normalising air travel for me. I'm currently on a flight from Dub to SFO with EI.

We're over Iceland and the seat belt sign is on as we hit turbulence. I'm sitting near rear of plane. The turbulence is light but the engines are throttling from high to low to regularly but we seem to be at the same height and speed. I'm kinda freaking out silently.

What could be causing the need for the engines to throttle high and low like that?

billie1b · 05-07-2014 02:23PM

faceman wrote: »

This is kinda a 'live' question!

I fly a lot and make no secret of the fact I'm a nervous passenger. I visit this forum a lot because it's a great way of normalising air travel for me. I'm currently on a flight from Dub to SFO with EI.

We're over Iceland and the seat belt sign is on as we hit turbulence. I'm sitting near rear of plane. The turbulence is light but the engines are throttling from high to low to regularly but we seem to be at the same height and speed. I'm kinda freaking out silently.

What could be causing the need for the engines to throttle high and low like that?

Ah there you are

smurfjed · 05-07-2014 02:46PM

Flight is most likely routing to avoid the wind, there is some light turbulence over Iceland, but it only has a single symbol, so its nothing to worry about. The engines are adjusting as the temperature changes.

Bigcheeze · 05-07-2014 04:24PM

faceman wrote: »

This is kinda a 'live' question!

I fly a lot and make no secret of the fact I'm a nervous passenger. I visit this forum a lot because it's a great way of normalising air travel for me. I'm currently on a flight from Dub to SFO with EI.

We're over Iceland and the seat belt sign is on as we hit turbulence. I'm sitting near rear of plane. The turbulence is light but the engines are throttling from high to low to regularly but we seem to be at the same height and speed. I'm kinda freaking out silently.

What could be causing the need for the engines to throttle high and low like that?

I've noticed that constant variation in engine tone a lot on the A330, particularly when travelling west to east when there's a strong jet stream helping us along. It's fairly subtle and most passengers probably don't notice it. I assumed it was the engines reacting to changes in the strength of the jet stream to keep us at whatever the assigned airspeed was. Could be completely wrong.

smurfjed · 05-07-2014 04:43PM

I assumed it was the engines reacting to changes in the strength of the jet stream to keep us at whatever the assigned airspeed was. Could be completely wrong

The aircraft is flying at a constant airspeed, the jet stream would actually affect the ground speed.

Tenger · 05-07-2014 05:48PM

faceman wrote: »

This is kinda a 'live' question!
......
What could be causing the need for the engines to throttle high and low like that?

Just the engines making adjustments to maintain speed as airflow fluctuates.

Neilw · 05-07-2014 09:48PM

I thought sheepskin seat covers went out of fashion years ago

Seems like most flight deck seats are this way, any reason behind it?

billie1b · 05-07-2014 09:58PM

Neilw wrote: »

I thought sheepskin seat covers went out of fashion years ago
Seems like most flight deck seats are this way, any reason behind it?

Breathability, it allows air circulation to flow behind the pilots back to stop them from get too hot and sweaty, also very comfortable

latynova · 06-07-2014 11:53AM

Hello pilots :-)

I just flew back from the UK on a 737 in 27 minutes (Manchester-Dublin). I'm wondering: what is the minimum distance/flight time that such a plane needs in order to operate safely?

Thanks!

Growler!!! · 06-07-2014 12:42PM

latynova wrote: »

Hello pilots :-)

I just flew back from the UK on a 737 in 27 minutes (Manchester-Dublin). I'm wondering: what is the minimum distance/flight time that such a plane needs in order to operate safely?

Thanks!

If the take off weight is more than the max landing weight (MLW) the aircraft must remain in the air until enough fuel is burned to bring its weight below the max landing weight. 73 drivers will give you the average figure.

If the the weight is already below max landing weight then it can safely fly short sectors as the Americans say " all day long "

The great big "ask an airline pilot" thread!

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