Ask The Pilot

[flychrisfly]

Coming in to land at DXB the other week we had a bit of a bumpy ride. The captain popped out of the coughpit after we landed and explained why the last few minutes of the flight (maybe 5-8 mins before landing?) were so rough - and it was for two reasons: 1) a bit of headwind, and 2) the plane in front was higher and we were flying through its wake vortex. Given we were on the part of the landing sequence where there are no more turns I would've assumed every plane would be on the same glide path and therefore every plane would be higher than the plane in front.
Any thoughts?

 

[jb747]

Coming in to land at DXB the other week we had a bit of a bumpy ride. The captain popped out of the coughpit after we landed and explained why the last few minutes of the flight (maybe 5-8 mins before landing?) were so rough - and it was for two reasons: 1) a bit of headwind, and 2) the plane in front was higher and we were flying through its wake vortex. Given we were on the part of the landing sequence where there are no more turns I would've assumed every plane would be on the same glide path and therefore every plane would be higher than the plane in front.

Dubai, at this time of year, is very hot. That leads to lots of thermals, and even the big aircraft will bounce around in them when down low. Headwind, per se, doesn't make it rough, but a gusty one would.

Wake. You often hit it for a few moments, but you shouldn't be consistently in any. It slowly descends away from the aircraft that formed it, so it's normally to be found below that aircraft's path. On an approach, that has the effect of putting it below the following aircraft. At Dubai though, there's some long STARs that most aircraft fly, which has them all flying the same track. Some heights are mandated, but not all, so it's quite possible for the aircraft to have quite different vertical paths (this only applies before joining the ILS glideslope, which happens at about 10 NM). If your aircraft were consistently below the aircraft above, wake could become an issue. Easily resolved by either matching, or flying a little above the preceding aircraft (which you can see on TCAS).

 

[747sp]

I was wondering in the past ,when it was legal, were flight crews allowed to smoke in the coughpit. If you could were the rules similar to those that applied to passangers ?

 

[jb747]

I was wondering in the past ,when it was legal, were flight crews allowed to smoke in the coughpit. If you could were the rules similar to those that applied to passangers ?

When smoking was allowed in the cabin, it happened in the coughpit. Those were hideous days. I recall one captain who used to light up a pipe. He was hated.

 

[Flashback]

When smoking was allowed in the cabin, it happened in the coughpit. Those were hideous days. I recall one captain who used to light up a pipe. He was hated.

Seems some airlines think it is still OK: We Tried To Call Out Our Flight Crew For Smoking... - One Mile at a Time

 

[lastrow]

Coming in to land at DXB the other week we had a bit of a bumpy ride. The captain popped out of the coughpit after we landed and explained why the last few minutes of the flight (maybe 5-8 mins before landing?) were so rough - and it was for two reasons: 1) a bit of headwind, and 2) the plane in front was higher and we were flying through its wake vortex. Given we were on the part of the landing sequence where there are no more turns I would've assumed every plane would be on the same glide path and therefore every plane would be higher than the plane in front.
Any thoughts?

I seem to remember several nasty situations where a smaller aircraft followed too close behind a B747. The wing vortices rotated the air with some force and following aircraft risked rotating as a result, in fact I think several did, even a 737.

There are strict separation rules now when flying behind some of this heavy metal. Maybe winglets reduce this vortex effect?

 

[jb747]

I seem to remember several nasty situations where a smaller aircraft followed too close behind a B747. The wing vortices rotated the air with some force and following aircraft risked rotating as a result, in fact I think several did, even a 737.

There are strict separation rules now when flying behind some of this heavy metal. Maybe winglets reduce this vortex effect?

Wake separation standards have existed for a very long time. I expect they predated the 747.

Winglets aren't designed to reduce the wake. They are meant to reduce the induced drag of an aircraft, and so make it more efficient. They may have a minor effect at reducing the intensity of the wake, but that's just a side effect. They actually harness some of the rotational motion as thrust. There's a good reference here... NASA - NASA Dryden Technology Facts - Winglets

 

[Saab34]

Do airlines have rules around age and retirements? Can a domestic driver still be going at 70?

 

[jb747]

Do airlines have rules around age and retirements? Can a domestic driver still be going at 70?

Yes.

Internationally, the age has moved around a bit over the years. It rose to 65 a while back, but beyond that you couldn't be in command. Suddenly, a year or so ago, the US changed it to a max of 65 for all ranks, and that's the state of play now.

We've had a number of international people move to short haul when they hit 65. I don't know how long they've stayed.

 

[mjt57]

We've had a number of international people move to short haul when they hit 65. I don't know how long they've stayed.

Lucky they don't fly for ANZ...

Air New Zealand 'shafted' elderly pilots over Airbus training | Stuff.co.nz

(dunno if this is a beatup or not. Possibly...)

 

[jb747]

Lucky they don't fly for ANZ...

Air New Zealand 'shafted' elderly pilots over Airbus training | Stuff.co.nz

(dunno if this is a beatup or not. Possibly...)

To be quite honest, if you've flown Boeing for your whole career, it's not surprising that some people have issues with Airbus conversions. I think the article has a large element of beat up.

 

[Quickstatus]

Today an A380 on the way to DXB returned to SYD.

VH-OQI attained FL300 before a rapid descent to FL100 and remained so for some time before landing in SYD.

Question about fuel jettisioning

Are there restrictions regarding location, altitude of this activity?

I understand that jet fuel despite having the consistency close to diesel will vaporise before reaching the ground, but is there an altitude minima?

 

[Orca]

.

Question about fuel jettisioning

Are there restrictions regarding location, altitude of this activity?

I understand that jet fuel despite having the consistency close to diesel will vaporise before reaching the ground, but is there an altitude minima?

Unless it's unavoidable, fuel dumping should occur at least above 6,000ft. ATC also must follow specific time and distance limits that segregate other air traffic from the vapour zone during and post-fuel dump.

 

[Orca]

Further to my above post, here is relevant excerpt from AIP (Australian Aeronautical Information Package)
66.5.2 When fuel dumping is required, the pilot in command should re- quest authority from ATC before commencing a fuel dump, and
must:
a. notify ATC immediately after an emergency fuel dump;
b. take reasonable precautions to ensure the safety of persons or property in the air and on the ground; and
c. where possible, conduct a controlled dump in clear air above 6,000FT and in an area nominated by ATC.

 

[straitman]

Today an A380 on the way to DXB returned to SYD.

VH-OQI attained FL300 before a rapid descent to FL100 and remained so for some time before landing in SYD.

Question about fuel jettisioning

Are there restrictions regarding location, altitude of this activity?

I understand that jet fuel despite having the consistency close to diesel will vaporise before reaching the ground, but is there an altitude minima?

Further to my above post, here is relevant excerpt from AIP (Australian Aeronautical Information Package)
66.5.2 When fuel dumping is required, the pilot in command should re- quest authority from ATC before commencing a fuel dump, and
must:
a. notify ATC immediately after an emergency fuel dump;
b. take reasonable precautions to ensure the safety of persons or property in the air and on the ground; and
c. where possible, conduct a controlled dump in clear air above 6,000FT and in an area nominated by ATC.

jb747 has covered this at least once before somewhere in the last 9800+ posts. :shock:

 

[Orca]

jb747 has covered this at least once before somewhere in the last 9800+ posts. :shock:

Correct, but it was way easier to answer again rather than try and find it ha!

 

[clazman]

Curious about cameras in the coughpit, are they allowed or is permission required from airline?

In some youtube videos, they cover the call sign plaque is there any real reason for this?

 

[clazman]

Businesses world wide are sweating on assets extending the shelf life, are we seeing this with airlines and will this result in problems in the long term?

 

[Quickstatus]

What would the apparent altitude be if a runway is 100ft above sea level with 993hPa and 49 deg celcius?

 

[Boris spatsky]

What would the apparent altitude be if a runway is 100ft above sea level with 993hPa and 49 deg celcius?

4780 feet - density altitude