Move COVID-19 Stuff

[J]

FAA warns of tail strikes, off-course flying by near-empty jets

One nearly empty passenger jet “climbed like a rocket,” prompting the pilots to exceed their assigned altitude. Others have scraped their tails on takeoff, gone off course, or strayed close enough to other aircraft to prompt mid-air collision alerts.

The common thread: the massive disruptions to the U.S. airline industry caused by the COVID-19 pandemic.

* * *
The Commercial Aviation Safety Team, comprised of the U.S. Federal Aviation Administration, unions, and airline officials, last month issued more than 50 warnings to carriers on the unusual factors they need to monitor more closely during the recent industry disruptions, according to documents reviewed by Bloomberg News.

They include tracking safety data related to unusually light aircraft, the stresses from employees fearing they could become infected by COVID-19, and possible fuel contamination on planes that were parked.

* * *
Details of incidents have begun to trickle out through NASA’s Aviation Safety Reporting System, which posts anonymous field reports after validating their authenticity.

They include pilots reporting that unusually light airliners behaved unexpectedly, such as climbing so fast that they exceeded assigned altitudes or couldn't maintain cabin air pressure. Others said the boarding process went so fast they forgot to finish safety paperwork.

Thousands of airliners are parked, some on runways at major airports. Normal flight routines are being disrupted. Training is being postponed. And airline crews face the looming threat of infection and a loss of job security.

“There is certainly a concern that all of these things could be a distraction to crews and could result in an undesirable situation,” said Hassan Shahidi, president of the nonprofit Flight Safety Foundation.

There have been no significant incidents, said Shahidi and others familiar with data collected by airlines.

NASA’s repository of reports from pilots, air-traffic controllers, and others reflect what Bahrami and Bristol have said. Reports of incidents in March have only just become public:

• An airline captain landing at Pittsburgh International Airport complained that planes were “parked all over” one of the runways, but it had not been marked as closed with lighted signs.
• A captain reported that an automated warning system ordered them to “climb” to avoid colliding with another plane. The pilot blamed it on another jet that was climbing faster than usual with a lightly loaded plane.
• An airline crew said they got a warning that the cabin wasn’t properly pressurized. They had been climbing so quickly with an unusually light load at high altitudes that the plane’s pressurization system couldn’t keep up, they said.
• Confusion over a missed radio call allowed two planes to fly too close to each other. A controller said that a nearby sector had been shut after another employee tested positive for the virus. “We were working abnormally complex traffic at a very high volume,” the controller said.
• After aborting a landing due to gusty winds, an airliner at takeoff power climbed so quickly that it exceeded its maximum assigned altitude. “To say I was rattled would be an understatement,” a pilot on the plane said. “I am concerned that we are flying these aircraft too light.”

https://www.inquirer.com/wires/wp/faa-w ... 00612.html

[3WE]

Interesting post.

Quote = J (with extensive snipping and paraphrasing)

3BS in red.

The common thread: the massive disruptions to the U.S. airline industry caused by the COVID-19 pandemic.

• An airline captain landing at Pittsburgh International Airport complained that planes were “parked all over” one of the runways, but it had not been marked as closed with lighted signs.

Um...OK, I see the lack of procedure, but could we address this by fundamental stuff like landing and taking off from assigned runways and following assigned taxi routes?

[J cites several instances of planes climbing faster than normal: over shoots, tail drags, pressurization issues]

Ok, but several years ago, lightly-loaded flights happened from time to time...And in the last two years, I (and I fall waaaaay short of TeeVee) have expereinced one or two BEFORE the travel crash.

[Gabriel]

Interesting post (agree with 3WE)

Black = J
Gabieeeie in red.

Others have scraped their tails on takeoff
It's not immediately obvious to me why the risk of tail strike (on take-off or landing) would be higher when the plane is light than when it is heavy.


gone off course
Off course? Because the plane is lightish? Weight acts in the horizontal axis too?

• A captain reported that an automated warning system ordered them to “climb” to avoid colliding with another plane. The pilot blamed it on another jet that was climbing faster than usual with a lightly loaded plane.
• After aborting a landing due to gusty winds, an airliner at takeoff power climbed so quickly that it exceeded its maximum assigned altitude. “To say I was rattled would be an understatement,” a pilot on the plane said. “I am concerned that we are flying these aircraft too light.”

Throttle controls vertical speed. Too much vertical speed? Reduce thrust.

• An airline crew said they got a warning that the cabin wasn’t properly pressurized. They had been climbing so quickly with an unusually light load at high altitudes that the plane’s pressurization system couldn’t keep up, they said.

This one makes no sense. From a cabin altitude point of view, the plane starts fully pressurized on the ground. The pressure differential is not there but that's because the external pressure has to drop, not because the the internal pressure has to increase, the internal pressure is never higher than when the plane is on the ground. There is nothing that the pressurization system needs to "keep up with" in terms of keeping the cabin pressurized while the plane is climbing at a given climb rate.

The only thing that can happen if you are climbing too fast is if you set the cabin vertical speed at a lowish value (like 500 fpm) and because the plane is climbing at 4500 fpm it will reach the point where the max pressure difference is achieved and at that point the outflow valve will open to keep the pressure difference constant at the max value, what means that the cabin altitude will increase at a higher-than-normal rate that may cause a lot of discomfort and pain in the ears. But that is not a lack of ability of the pressurization system to keep the plane pressurized.

As a simplified example, say that the airplane climbs from ground to FL360 at 4500 fpm constant. It would take 8 minutes to get there. Because the maximum cabin altitude is 8000 ft, you would need a cabin climb rate of 1000 fpm, which is not terrible but certainly more discomfortable an painful that what you normally experience in your typical flight.

However, the real problem is if you set up the system to climb the cabin at a more typical 500 FPM. Then when you reach FL360 the cabin would be only at 4000 ft. This would probably exceed the maximum differential pressure permitted, so upon reaching said maximum the outflow valve would open to keep the max differential pressure, and that means that the cabin will climb way faster, at thousands of feet per minute.

Solution for this? There are 2:
- Set up a faster cabin climb rate so the time to get to 8000 ft matches the time to get to your cruise altitude, or...
- Once again, throttle back and climb at a more moderate climb rte.
This should be identifiable during the flight preparation.

So all of the above are related to the airplane being light.

As 3WE said, it is not that uncommon that airplanes are light.
I have flown in almost-empty planes before, and also very short flights (like 20 minutes) where the plane would be very light on fuel.
And also there have always been repositioning flights and post-maintenance test flights.

While the frequency of "light planes" may be higher now, it should not be a "new skill" for pilots.

Then you had Pinnacle...

• Confusion over a missed radio call allowed two planes to fly too close to each other. A controller said that a nearby sector had been shut after another employee tested positive for the virus. “We were working abnormally complex traffic at a very high volume,” the controller said.
Ok, but this has happened also in other circumstances, like a power outage, or an evacuation due to earthquake or fire in the ATC center.

[Not_Karl]

Does the reduced mass of empty aeroplanies make them less prone to attract meteors?

[Gabriel]

Does the reduced mass of empty aeroplanies make them less prone to attract meteors?

Sure, less mass = less gravitational attraction. Bit the other side of the coin is that they are susceptible to accidentally get into orbit like what happened in this accident:

https://www.youtube.com/watch?v=wZUzUfBfeK8

[Not_Karl]

Bit the other side of the coin is that they are susceptible to accidentally get into orbit like what happened in this accident:

https://www.youtube.com/watch?v=wZUzUfBfeK8

Good point, I didn't remember that accident, only the one that was the opposite....
Ban all aeroplanies!

[Gabriel]

I think this one better demonstrate the dangers of gravity attraction between 2 airborne objects:

https://www.youtube.com/watch?v=s8H0Fi6jviQ

But we better wait for the final NTSB report.
Or for Joe Patroni.

[elaw]

the opposite

"Nobody's going to drown - the plane is pressurized!"... "Radios don't work underwater"

[3WE]

[Advertisment for Starflight one]

WOW, I NEED TO WATCH THAT MOVIE...WHAT AN ALL-STAR CAST...THE $6,000,000 MAN.

Will there be a movie with Wesley Snipes: Viruses on a plane?

[Not_Karl]

"Nobody's going to drown - the plane is pressurized!"... "Radios don't work underwater"

I have some doubts on some of the events shown in that documentary. I wonder if the final report is out...

But we better wait for the final NTSB report.

Concur.