Ask The Pilot

[justinbrett]

Perhaps there will be two pilots, but the FO has to serve drinks during cruise

 

[mel-world]

Interesting pattern from FR24 by a Cessna 404 at 13,000ft over Melbourne this morning. I can only assume that it was doing aerial filming of some sort but was wondering how it would affect traffic into and out of MEL, given that the approach was from the South. I did note that QF1552 from Hobart had to descend below 13,000 ft quite early.

 

[jb747]

Interesting pattern from FR24 by a Cessna 404 at 13,000ft over Melbourne this morning. I can only assume that it was doing aerial filming of some sort but was wondering how it would affect traffic into and out of MEL, given that the approach was from the South. I did note that QF1552 from Hobart had to descend below 13,000 ft quite early.

I would expect there wasn't much effect at all. FL130 at a max of about 20 nm from the airport is appreciably above the heights used by the inbound flights. At 20 nm to run, most traffic would be around 5,000', so even with buffers applied by ATC, there wouldn't seem to be much need to make aircraft descend noticeably earlier. 1552 doesn't strike me as all that early.

 

[Daver6]

Interesting pattern from FR24 by a Cessna 404 at 13,000ft over Melbourne this morning. I can only assume that it was doing aerial filming of some sort but was wondering how it would affect traffic into and out of MEL, given that the approach was from the South. I did note that QF1552 from Hobart had to descend below 13,000 ft quite early.

View attachment 328213

Looks like some kind of mapping/survey to me. Maybe Nearmap kind of thing.

 

[Flashback]

Looks like some kind of mapping/survey to me. Maybe Nearmap kind of thing.

Beat me to it. Exactly this. Definitely GIS related.

 

[gaz0303]

Any comment on OZ8124? I thought opening doors in flight was a bit harder work than what is being reported. Thanks

 

[jb747]

Any comment on OZ8124? I thought opening doors in flight was a bit harder work than what is being reported. Thanks

Interesting. Some aircraft doors are what are called plug doors. They cannot be opened in flight, because the first part of their opening action pulls them inwards, and as that is against all of the pressure on the door, they won't move. I don't think this particular door is a plug. They weren't on the 380. I'll have a look at the manual in the next day or so, but from memory the pressurisation controller dumps the pressure late in the approach, with the outflow valves opening fully on touchdown. The upshot is that at low level (below 500' or so) on approach there would be little to no differential, and yes, the door could potentially be opened. The pressure has to be dumped to ensure that the doors can actually be opened safely if there is an emergency on the ground. If they are opened with even a tiny amount of residual pressure, they will literally launch the person holding the handle out of the aircraft. This killed a purser in the USA a few years ago.

 

[Skyring]

I would expect there wasn't much effect at all. FL130 at a max of about 20 nm from the airport is appreciably above the heights used by the inbound flights. At 20 nm to run, most traffic would be around 5,000', so even with buffers applied by ATC, there wouldn't seem to be much need to make aircraft descend noticeably earlier. 1552 doesn't strike me as all that early.

That reminds me of a spectacular image of a 747 launching from LAX. Taken from above. Apparently there is a VFR route used by general aviation that passes along the shoreline over the flight path of airliners taking off from LAX. (The shot looks like it was taken from directly in front and not too far distant but that would be some super long lens in use. I hope.)

I don't see too many similar shots so I'm guessing that even with serious height separation this sort of thing isn't too common?

 

[Skyring]

…but from memory the pressurisation controller dumps the pressure late in the approach, with the outflow valves opening fully on touchdown. The upshot is that at low level (below 500' or so) on approach there would be little to no differential, and yes, the door could potentially be opened. …

Larger airliners are one thing but I notice that in the Dash-8 there are often infants crying during the descent which I take to be the result of pressure changes affecting their ears. Not too long ago FAs used to hand out lollies to suck but I haven't seen this happening for a while. Do different aircraft have different pressurisation/depress regimes?

 

[MEL_Traveller]

There’s a report courtesy of onemileatatime that a passenger opened an a321 door on final approach (around 1000 feet). No major injuries.

I’m not surprised about being able to open the door in those conditions, but discussion in the thread says that some boeing aircraft can actually lock doors until touchdown. As in not just pressure keeping the door from opening, but they can be physically locked. Is that true?

 

[RooFlyer]

I know this isn't a pilot question, but I thought our pilots may get some amusement (at the pilot's expense) out of the solution to this

Oops: Southwest Passenger Locks Pilots Out Of coughpit

 

[AviatorInsight]

I know this isn't a pilot question, but I thought our pilots may get some amusement (at the pilot's expense) out of the solution to this

Oops: Southwest Passenger Locks Pilots Out Of coughpit

Lol. Umm….clearly pilots who don’t understand how the system works. What did get me though is that they decided to board without any flight crew? I wonder if there was any power to the aircraft. I guess it’s why our procedures are very different.

 

[AviatorInsight]

There’s a report courtesy of onemileatatime that a passenger opened an a321 door on final approach (around 1000 feet). No major injuries.

I’m not surprised about being able to open the door in those conditions, but discussion in the thread says that some boeing aircraft can actually lock doors until touchdown. As in not just pressure keeping the door from opening, but they can be physically locked. Is that true?

The overwing exits on the 737 are definitely ‘locked’ in place until the aircraft is on the ground and few other parameters are met. The entry and service doors aren’t ‘locked’ as such, more a case of plugged into place. Just prior to touchdown there will still be some residual pressure which could technically be overcome until the outflow valves fully open on landing.

The 777 does have locks on all doors when airspeed gets above 80kts.

 

[jb747]

I know this isn't a pilot question, but I thought our pilots may get some amusement (at the pilot's expense) out of the solution to this

Oops: Southwest Passenger Locks Pilots Out Of coughpit

I recall that the engineers managed something similar on a QF767 around the time these doors were being fitted. They test locked the door, but without anyone on the inside. And as Murphy was present, the access code they thought they'd entered wasn't correct. Their solution was to disconnect some of the electrics downstairs, and the door automatically unlocked when the busses were unpowered.

Lol. Umm….clearly pilots who don’t understand how the system works.

So it would seem. There was very easy way past this on every aircraft I flew that had these doors. Is it possible for one door to physically block the other?

What did get me though is that they decided to board without any flight crew? I wonder if there was any power to the aircraft. I guess it’s why our procedures are very different.

It was allowed by QF in some cases (though I forget the exact rules now).

The overwing exits on the 737 are definitely ‘locked’ in place until the aircraft is on the ground and few other parameters are met. The entry and service doors aren’t ‘locked’ as such, more a case of plugged into place. Just prior to touchdown there will still be some residual pressure which could technically be overcome until the outflow valves fully open on landing.

The 777 does have locks on all doors when airspeed gets above 80kts.

Are the doors physically locked, or just the handles? I'd guess that it was the same system as the upper deck on the 747, and that was just a handle lock. As the pressure differential built up, there was eventually so much load on the locks themselves that there was no way they could be withdrawn. For that reason, the locking system was an MEL item....you could go without it, as long as the seat belt signs were on until above a few thousand feet (and the door had a cabin crew member present).

Looking at the A380 manual, and assuming that AB would use similar logic on the 320.

During descent, the cabin vertical speed is controlled to ensure that the cabin altitude reaches an altitude slightly BELOW the landing field altitude prior to landing. The cabin pressure reaches the landing field pressure +0.1 psi, 1 minute before landing. At touchdown, all outflow valves open, to remove the residual pressure.

There is a flight lock actuator in each door that locks the door handle during the climb and descent phases, in order to prevent inadvertent actuation in flight.
The flight lock actuator releases the door handle in the following cases:
- During cruise (the differential pressure will prevent the doors from opening)
- If the aircraft is on the ground
- If it detects a failure of the lock actuator, or monitoring system.

The flight lock activates at 65knots, and remains locked until the aircraft reaches FL240. The manual doesn't specifically say where it unlocks at the other end, though I would presume touchdown.

The upshot of all of that is that the door handle should still have been locked when the passenger decided to leave.

 

[MEL_Traveller]

The overwing exits on the 737 are definitely ‘locked’ in place until the aircraft is on the ground and few other parameters are met. The entry and service doors aren’t ‘locked’ as such, more a case of plugged into place. Just prior to touchdown there will still be some residual pressure which could technically be overcome until the outflow valves fully open on landing.

The 777 does have locks on all doors when airspeed gets above 80kts.

Thanks!

 

[AviatorInsight]

So it would seem. There was very easy way past this on every aircraft I flew that had these doors. Is it possible for one door to physically block the other?

There’s only one door? My guess here is that someone from the last crew forgot to unlock the door master switch on their way out when they left.

But even if the aircraft was powered there is still 2 more methods to gain access without going through the window.

It was allowed by QF in some cases (though I forget the exact rules now).

Definitely not at VA. We can board without the CM and the FO can give approval without the Capt but at least one flight crew member must be present.

Are the doors physically locked, or just the handles? I'd guess that it was the same system as the upper deck on the 747, and that was just a handle lock. As the pressure differential built up, there was eventually so much load on the locks themselves that there was no way they could be withdrawn. For that reason, the locking system was an MEL item....you could go without it, as long as the seat belt signs were on until above a few thousand feet (and the door had a cabin crew member present).

The main entry doors are locked at all. Rotating the door handle to closed only latches the door in place so it doesn’t move. It is on these latches that we get the door master caution if either the handle isn’t in the closed position of the door itself isn’t secure properly. What ends up locking it are the gates at the top and bottom of the door (they actually move when the handle is in the open position to make door fit through the frame) that actually plug the door in flight once there’s any real cabin diff applied.

The over wings are different and are actually locked in place. Similar to the upper deck of the 747, we need to have a cabin crew member present at the door if the automatic locking is unserviceable.

 

[jb747]

There’s only one door? My guess here is that someone from the last crew forgot to unlock the door master switch on their way out when they left.

I was just wondering if the toilet and coughpit doors could interact with each other. It know that it’s a narrow space.

But even if the aircraft was powered there is still 2 more methods to gain access without going through the window.

Three if you count the axe.

What ends up locking it are the gates at the top and bottom of the door (they actually move when the handle is in the open position to make door fit through the frame) that actually plug the door in flight once there’s any real cabin diff applied.

The flight manuals don’t expand on the actual mechanical functions of the doors, so I’ll have to see if one of my engineer friends has any more info on this. But, the only aircraft that I know of on which any real force was applied to the door handle in flight was QF30, and whilst the door’s internal mechanism sheared, the gates actually opened. No pressure differential either…

 

[AviatorInsight]

I was just wondering if the toilet and coughpit doors could interact with each other. It know that it’s a narrow space.

They can stick together but it’s really only an issue when the coughpit door is open. I hate it during turnarounds when I’m in the bathroom and they open the coughpit door fully which prevents the toilet door handle from opening. It‘s a fine art on getting it unstuck.

Three if you count the axe.

Which is inside the coughpit.

 

[Saab34]

AV when will you get your captain upgrade? I remember you said there was a delay in recent times. With the new era of no staff and pilots resigning to join other carriers, has this sped up your command?

 

[Carrots]

Three if you count the axe.

Management would love that