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ANA and Japan Airlines ground all 24 787 aircraft

Boeing's 787 Dreamliner has suffered multiple problems across the aircraft fleet this month. Boeing’s 787 Dreamliner got another ding on its record yesterday when an All Nippon Airways (ANA) aircraft had to make an emergency landing.
 
What is known about the emergency landing is that the cockpit display showed that the aircraft was having battery problems. Presumably, after the battery fire in Boston, pilots were taking no chances and landed the aircraft as soon as possible.
 
The batteries in these aircraft are especially important because the 787 Dreamliner fleet uses electrical systems rather than hydraulic systems found on most passenger aircraft.


All Nippon Airways 787 after emergency landing. [Image Source: Kyodo News]

After these issues, all 24 of the Boeing 787 Dreamliner aircraft operated in Japan by ANA and Japan Airlines have been grounded for safety checks. ANA owns 17 of the 24 aircraft with Japan Airlines owning the remainder. These 24 aircraft are nearly half of the 50 787 Dreamliners that have been delivered and flown commercially around the world.

In response to the issues with the aircraft, the FAA has launched a comprehensive safety review of 787 Dreamliner’s critical systems. This review will include an evaluation of how Boeing designs, manufacturers, and assembles the aircraft. Boeing has pledged to fully participate in review stating that it believes the process would bolster public confidence in the aircraft. 

Source: LA Times



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RE: Lithium Ion Batteries?
By Samus on 1/16/2013 10:31:55 PM , Rating: 2
quote:
lithium ion don't discharge quickly as well as lead acid, that's why they work great for phones


That is complete bullshit.

Lithium batteries are capable of discharging and recharging at ridiculous rates, some more-so than others.

I've jumpstarted a truck with a 12.4v 4200mAH R/C Car lithium pack and it got warm, but hey, that's a 150 AMP draw, draining the capacity of the battery at 35 times its capacity. Some consumer packs are rated at 50C and higher (50 times capacity draw!)

Charging is different. Most packs are 2C-5C (not to be confused with 'cells', this means you can charge the pack at 2-5x its capacity.) For example, most cell phone battery packs are rated at 1C because they are crap, so a 2200mah battery pack shouldn't be charged at more than 2.2amps. An iPad charger puts out 5v@2a, so if you wanted to charge your 1500mAH iPhone battery in under an hour this would be a way to do it. The battery will get warm, but this won't shorten its life or do anything unsafe. The voltage cutoff and thermal monitor will shut off the charging and wait for it to cool, then resume, if ambient temps are too high for this to happen.

What I suspect Boeing is going to do is replace the chemistry with LiFePO4 or something else more stable at extreme cold/high temperature, pressure and vibration.

Lithium Ion is very delicate to any extreme, Lithium Polymer improves temperature and pressure tolerances but can still become unstable if super-heated or impacted. LiFePo fixes almost all of this, and since Aerospace is generally a safety-rules-all sector, spending a few extra grand on reliable batteries won't be a big deal.

Here's some basic consumer-level information of Li-Ion/LiPo for anybody curious:

http://www.rcgroups.com/forums/showthread.php?t=20...


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