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B737 design flaw, pilot error induced by B737 design

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luckytohaveajob

Well-known member
Joined
Nov 17, 2005
Posts
1,114
Boeing has a flawed system design. Using the same non-descriptive horn to represent two separate functions is the problem, not giving pilots one more exception to the rule.


Boeing's insistence on it infallibility is Boeing's biggest failure. Boeing overall build a good product. But Boeing's over inflated sense of superiority is the reason Airbus has made the progress it has made in recent times.


AP
FAA renews, toughens warning to Boeing 737 pilots
Monday November 10, 5:39 pm ET
By Tim Klass, Associated Press Writer
FAA requires flight manual change to remind Boeing 737 pilots, 'Don't ignore warning horn'
SEATTLE (AP) -- The Federal Aviation Administration has toughened a requirement that Boeing 737 pilots be reminded not to ignore a cabin pressure warning horn, ordering preflight briefings as well as changes in manuals.if(window.yzq_d==null)window.yzq_d=new Object(); window.yzq_d['bN2ABNG_XLc-']='&U=13f40b4rv%2fN%3dbN2ABNG_XLc-%2fC%3d626899.12894134.13150363.1383221%2fD%3dLREC%2fB%3d5133107%2fV%3d1';
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The airworthiness directive, issued Monday and effective Nov. 25, stems from a crash in which 121 people died on Aug. 14, 2005, when a Helios Airways 737-300 slammed into a hillside north of Athens, Greece.
Greek investigators determined that the pilots had lost consciousness because of a cabin pressure failure shortly after takeoff on a flight from Nicosia, Cyprus, and that the plane kept going on autopilot for two hours until it ran out of fuel.
Authorities say the cabin pressure control settings had been operated improperly and that an alarm went unheeded. Last Tuesday the attorney general of Cyprus said five people would face criminal charges for the crash.
The FAA's order applies to all Boeing 737s, the world's best-selling commercial jet with more than 6,000 orders since the model was launched in 1965 and 5,397 in use worldwide, and takes effect in 120 days. Public notice and comment requirements were waived "because an unsafe condition exists that requires the immediate adoption" of the directive, according to the notice.
Changes in the manuals must be made by each airline. The process is complex, varying by aircraft as well as the nature of the change, and new wording must be validated before it can take effect, FAA spokesman Les Dorr said.
FAA directives typically are reissued by civil aviation authorities in other countries.
Airlines with large number of 737s, according to the Web site http://www.airfleets.net, include Southwest with 541 planes, Continental with 259, Ryanair of Ireland with 168, United with 162, Alaska with 110, Air China with 107 and China Southern with 102. Southwest, Ryanair, Alaska and some smaller carriers have all-737 fleets.
Chicago-based Boeing Co. and FAA representatives said the cockpit warning horn serves a dual purpose. On the ground it indicates something is wrong with the plane's pre-takeoff configuration, such as the setting of the wing flaps. In the air it means a loss of cabin pressure, which can cause pilots to lose consciousness if they don't immediately put on oxygen masks.
The FAA directed on July 7, 2006, that flight manuals be changed to remind pilots to pay heed to the warning horn after takeoff, but "we have received continuing reports of in-service events involving failure of the flight crew to recognize and react property to valid cabin altitude (air pressure) warning horns," according to the latest directive.
Dorr wrote in an e-mail that between the Helios crash and the first directive, the FAA received four reports of pilots disregarding the alarm, all from U.S. carriers which he did not identify. Since then there have been three reports from carriers that were not identified by country, he added.
Such problems in other countries typically are reported to civil aviation authorities who then notify the manufacturer, in this case Boeing, which in turn alerts the FAA, Dorr said.
Before the Helios crash, Boeing was alerted to "some cases where flight crews were getting confused" about the alarm horn and advised airlines "to do a little crew training on that," Boeing spokeswoman Liz Verdier said.
After the FAA's initial directive, which largely incorporated Boeing's advisory note, the manufacturer began working on a change in the cockpit and flight deck design to incorporate a warning light that will provide a second indication of cabin pressure loss when the horn sounds, Verdier said.
"Within the next month or so," she said, Boeing expects to have the change ready to incorporate into production of current models, the 737-700, -800 and 900, followed by production of retrofitting kits for earlier models a few months after that.
The FAA may propose further action to "address the unsafe condition" once the warning light kits are available, according to the airworthiness directive.
 
horn e article.....
 
If you ever had this happen to you (especially the first time) you would know how distracting and confusing it may be. At low altitude or in the Takeoff segment its a real handful with everything else thats going on. Usually the ivsi on the pressurization panel is pegged at 4000 fpm. It also appears your in negative pressure since the needle is below zero. Then you question your self if its + or - 4000 fpm since its right in the middle of the very small gage. Best bet it to level off and don't climb anymore till problem is fixed or return to airport. But thats not what always happens and the horn gets disregarded for a Takeoff warning malfunction which is now way behind where your at on your flight segment profile. There should have been 2 different horns/tones/alerts from the beginning to eliminate this issue.
 
If you ever had this happen to you (especially the first time) you would know how distracting and confusing it may be. At low altitude or in the Takeoff segment its a real handful with everything else thats going on. Usually the ivsi on the pressurization panel is pegged at 4000 fpm. It also appears your in negative pressure since the needle is below zero. Then you question your self if its + or - 4000 fpm since its right in the middle of the very small gage. Best bet it to level off and don't climb anymore till problem is fixed or return to airport. But thats not what always happens and the horn gets disregarded for a Takeoff warning malfunction which is now way behind where your at on your flight segment profile. There should have been 2 different horns/tones/alerts from the beginning to eliminate this issue.

Agreed; until you have this happen to you in the heat of the moment you cannot appreciate just how confusing it can be.
 
I love the solution: everyone does it wrong, so do they change the warning system, or do they just emphasize that it's really, no I mean really really important that you not screw it up.

"management by memo not incentive". Duh. I can't believe Boeing hasn't had to pay out $100 million because of this stupid system. How much would it cost to have the GPWS say, "Cabin Pressure Warning. Cabin Pressure Warning".

No, instead they're going to issue memos and make stuff bold print. Nice.
 
no NASA app required

Lets not make more out of this than needed. It's not that hard. If you get an intermittant horn, you only need to ask yourself one question. Am I on the ground? If yes, then its a Takeoff warning horn. If No, then grab the mask.
In the Air = grab the mask. Simple.
 
Lets not make more out of this than needed. It's not that hard. If you get an intermittant horn, you only need to ask yourself one question. Am I on the ground? If yes, then its a Takeoff warning horn. If No, then grab the mask.
In the Air = grab the mask. Simple.

Nicely put!!!!
 

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