Southwest B733 decompression incident

http://news.uk.msn.com/world/articles.aspx?cp-documentid=156840226

Reading about this decompression, emergency descent and safe landing, debated on another forum, I was interested in the following figures regarding the aircraft involved.

N632SW, B737-300, delivered to SW 13.6.96.

The aircraft is 15 years old. Total hours to date, 48,722, total cycles to date 39,768. That means 1.225 hours per cycle.

If these figures are correct, this aircraft on average has been in use daily for nearly 9 hours out of 24 for the past 15 years.

48722 divided by 15 = 3248 divided by 365 = 8.9 hours per day.

SW is the mother of LCC flying with more experience of the concept than any other airline but should we be hearing warning bells given this intense level of aircraft utilisation?

SW has taken a sub-set of its 737 fleet out of service pending investigation, 81 aircraft are affected.

You may remember a similar upper fuselage detachment with an Aloha Airlines B737 back in 1988.

A more intelligent report on this incident.

http://www.flightglobal.com/articles/201

I don't think hi-cycles, hi-flight hrs and intense utilization are the problems. Modern airframe designs are tested & certified to endure abuses well beyond the utilization data recorded for airframe N632SW U hv quoted IF the operator follows EXACTLY the relevant maintenance procedure+schedule which is seriously expensive for hi-cycle/hi-hours airframes.

Unfortunately, operators don't always maintain such hi-level of discipline+financial commitment.

The Aloha 737 incident was a special case. Their 737 Original<A 732 was involved in that accident which unlike Southwest's 733, was designed in the late 60s> was among the 1st jet airframe types to fly in such unique op environment EXCLUSIVELY: Hi-cycle, super-short sectors<Basically no flight exceeds 1hr>, tropical oceanic weather<Hi-salt content in the air yr-round>. Both airframe and maintenance procedure designs were based on much less comprehensive data about such op environment than we have today.

FLX - I take your point about the Aloha incident, but the FlightGlobal site message I quoted also referred to an event in July 2009, when one of their B737 was holed in the upper fuselage on a flight from Nashville to Baltimore. (Sector length 1 hr 30 mins) The flight diverted to Yeager. I have no other details on this event. I am not aware if Boeing issued any directives or advisories after this incident..

Like I said earlier:
Unfortunately, operators don't always maintain such hi-level of discipline+financial commitment.

I enforce that is maintenance ckeck problems...is SWA doing a great job???
I agree totally with you FLX: operators don´t always maintain such hi-level of discipline plus financial commitment.

http://www.msnbc.msn.com/id/42434710/ns/travel-news/ It appears now that the blame for this incident is shifting from WN to Boeing. Until now Boeing has claimed that the structural integrity of the 733/4/5 fuselage was guaranteed through 60,000 cycles (the WN 733 had 39,000+), but Boeing has now revised their claims to only guarantee through 30,000 cycles before major overhaul repairs are needed. Boeing has now advised other 733/4/5 operators such as AS, LH, US and QF of this issue, so it looks as now other carriers will begin temporarily grounding their 733/4/5 fleets to make the necessary repairs. We should all be glad this issue was brought to Boeing's attention before anyone got killed.

When it rains it pours...the 787 debacle and now this.

http://www.msnbc.msn.com/id/42437823/ns/travel-news/?GT1=43001 Sorry, this was the link I meant to post with my above message.

The issue affects 579 airframes worldwide - only ones with a certain modification. Out of that only 175 have high enough cycles (above 30k) to require inspections. Of course as time elapses, more and more of those 579 planes will need to be inspected regularly.

Details are here:
http://www.flightglobal.com/articles/2011/04/06/355216/boeing-issues-service-bulletin-for-premature-737-classic-lap-joint.html

UPDATE: All WN's 733s have been inspected per Boeing's revised guidelines and they've been back to operating at full schedule since yesterday (Wednesday) morning. 2 more fuselage cracks have been found and these frames are being taken out of fleet for repairs. US, QF and LH are inspecting their 733/4/5s this week as well.

Again, thank goodness this problem was discovered before anyone got killed.

I´m not sure if that´s correct but i´ve read somewhere that are about 931 still flying :/

LH has 33 733 if i´m correct, they ordered the A320 neo so it´s time to replace older airframes...... :/