Lots of failures of front of engine/cowling on airliners these days

[Vraciu]

You are not being objective if you intentionally misrepresent the information in your own link. The precautionary landing in Cleveland was for a cracked window.  It was not blown out.  Read your link again and look at the picture.  Either you have something against Southwest or you don’t have a grasp on facts, or both.  What ever your agenda is about Southwest, it is not based on factual information.

This is a good point.

The original window failure that brought all this on wasn't even related to this one.    That incident was due to an engine failure and the window was broken as a result of collateral damage.    Windows rarely just break to the point of total failure.  They crack and delaminate sometimes, heck they even blow off because someone used the wrong size screws to fasten them (British Airways 5390, BAC-111, June 1990), but they don't tend to "blow out" without some sort of trauma.

[Skuzzy]

What is the maintenance schedule for windows?  Is there one?

[Puma44]

What is the maintenance schedule for windows?  Is there one?

The jets go through a comprehensive maintenance schedule with specific depth of inspection at progressive time points.  Not sure how the windows fall in that schedule.  Every 7 days, a Southwest mechanic does an airworthiness inspection on each jet and signs it off.  Again, not sure what the specific requirements are of that inspection.  The mechanics would typically show up after the last leg of the night and start looking at the overall condition, lights, systems, etc as we gathered up our gear departed for the night.

As stated previously, Southwest Mechanics have plenty of skin in the game. They do not take shortcuts and will not hesitate to take a jet out of service if it doesn’t meet Southwest’s high standards.

This current dust up in the “news” media is a result of a slow news day.  There are mechanical issues with airliners every day.  Those issues are dealt with properly by the flight crews and mechanics. The jets continue on or are taken out of service. 

Airliners are kept in far better mechanical condition than the average person takes care of their car.

[Mister Fork]

The jets go through a comprehensive maintenance schedule with specific depth of inspection at progressive time points.

Correcto Puma... airplanes have a maintenance schedule similar to that of a vehicle. (from 737 Heavy Maintenance)
The 737 like all airliners undergoes periodic heavy maintenance this page describes soem of the maintenance programs and checks involved.

The first photograph below was taken whilst the aircraft was on a D check as part of the end-of-lease process. Most airlines lease rather than own their aircraft. Large airlines will often place a large order for aircraft with the manufacturer, then as soon as they are delivered, they will immediately sell them to a leasing company and lease them back on a fixed term, say for 7 or 9 years. This frees up capital for the airline.

One of the conditions for the handback of the aircraft to the leasing company is that the aircraft is returned to the lessor in as good a condition as it was given. Whilst it is impractical to have a 7 year old aircraft in new condition, the accepted compromise is that a heavy maintenance program be completed before handback. With the typical high utilisation of a low cost carrier this equates to a P48 check which has a maintenance interval of 24,000 flight hours (FH). Such a check used to be known as a “D” check.

The maintenance check periods and nomenclature is approximately as follows:

A check – every 500 FH. Now known as a P1 check
B check – every 6 months. Often incorporated into A or C checks
C check – every 4-6,000 FH / 2-3 years. Now P8, P10 or P12 checks
D check – every 24-40,000 FH / 9-12 years. Typically a P48 check
For example, a D check they basically strip the interior of the aircraft and then to x-rays of various key components, looking for micro fractures and other stress related issues to major components not visible with the human eye.  Nowadays, they also use AI software to assist mechanics in the analysis of the x-rays and other safety systems.

737 gutted for a D inspection

[Vraciu]

What is the maintenance schedule for windows?  Is there one?

Every single part on the airplane has a schedule.  A Continuous Airworthiness Maintenance Program (CAMP) is how most do it.  Everything is in the computer and at specified intervals the airplane is given a workover.  As the plane ages the inspections become more intense until we get to the 144-month at which time the airplane is almost completely rebuilt.    Then it starts over. 

Windows are in this program but they’re also on-condition (like any part) meaning you replace them if something is wrong.  We have manufacturer criteria for tolerance on things like delamination or scratches.   Anything too big or too deep means we replace it.

EMBRAER actually tracks every single part in the fleet and can give you a predicted failure time/date.   If the plane is in for inspection and a part is closing in on it’s expected failure it can be proactively replaced.   

At the end of the day this is why the industry went almost a decade without killing anyone.  It’s an amazing thing.

[Ciaphas]

Pre flight, through flight, post flight, phase minor and major (typically dependent on flying hours), depot level maintenance and all sub systems have their own work carded items that have inspection intervals aligned with phase, depot and and system specific requirements.


Sent from my iPhone using Tapatalk

[Puma44]

Great info Fork!  Interesting how much factual information can be found with a little effort vs making up info to support a slanted agenda.  Thanks for the effort and posting. 

[Vraciu]

Pre flight, through flight, post flight, phase minor and major (typically dependent on flying hours), depot level maintenance and all sub systems have their own work carded items that have inspection intervals aligned with phase, depot and and system specific requirements.


Sent from my iPhone using Tapatalk

Depends on utilization.  There is a high utilization and a low utilization schedule.  Hours *AND* cycles are determining factors in each.   If you reach an hourly limit first you do the inspection on that basis.   If you reach a cycles limit first you do it for that reason instead.

   

[Ciaphas]

Yeah minors and majors, it’s what I do for a living 20 yrs +

It’s all based on calendar and hours


Sent from my iPhone using Tapatalk

[Vraciu]

Yeah minors and majors, it’s what I do for a living 20 yrs +

It’s all based on calendar and hours


Sent from my iPhone using Tapatalk

Depends on the utilization.   We have inspections due on CYCLES, hours, and the calendar.     I do this for a living, too, and every time I sign for the airplane I'm responsible for ensuring I do not overfly any of the three.

 

[Ciaphas]

Oh I agree with you brotha, without cats like you and I ain’t a darn thing taking off.

<salute>


Sent from my iPhone using Tapatalk

[Vraciu]

Oh I agree with you brotha, without cats like you and I ain’t a darn thing taking off.

<salute>


Sent from my iPhone using Tapatalk

Amen.   You guys are the best.   

[Puma44]

Ditto!

[Delirium]

You are not being objective if you intentionally misrepresent the information in your own link.

Speaking of being objective, do you work for Southwest?

[Vraciu]

Speaking of being objective, do you work for Southwest?

No, he does not, and neither do I.  But we both have an understanding of how things work on the inside--him more so than I in this SPECIFIC case.


Next.