my ipad air is crashing all the time after the ios 8.3 update. he goes on with the apple logo and then in never comes to lockscreen but is goes off.... I need my ipad for homework and tests for tomorrow... plzz help me

A word of advice ... Don't make changes before a deadline.

You can still downgrade to 8.2. Might be able to revert to previous version if the ideas below don't work.

See here for your device.

http://api.ineal.me/tss/status

see the post by arizonacat and others in this thread.

https://discussions.apple.com/thread/5337442?tstart=0

arizonacat points out these sites:

• Provides easy access to Apple firmware files.
  http://www.ipswdownloader.com/
  
  
• How to install the ios software. The install will erase your exiting data. Backup your existing data.
  http://osxdaily.com/2010/11/23/how-to-use-ipsw-files/
  

Re-boot ipad.

Press and hold the Sleep/Wake button until a red slider appears, then drag the slider. Then press and hold the Sleep/Wake button until the Apple logo appears. page 128 iPad user manual.

force power down if the above give you trouble.

Hold down both the Sleep/Wake button and the Home button. Ten seconds or more. Hold until the Apple logo appears.

more details on re-booting:

http://ipad.about.com/od/iPad_Guide/ss/How-To-Reboot-Your-iPad-Power-Off.htm

Restore to factory settings by loading the latest version of ios that your machine will support:

Do a full backup of your device. Twice is best -- cloud and computer.

"You can use iTunes to restore your iPhone, iPad, or iPod touch to factory settings and the latest version of iOS."

http://support.apple.com/kb/HT1414?viewlocale=en_US&locale=en_US

"You can put your iOS device into recovery mode, then restore it using iTunes.:

http://support.apple.com/en-us/HT201263

At last resort you could consider DFU (Device Firmware Update). This could void your warranty.

http://www.imore.com/tip-put-iphone-ipad-dfu-mode

Is your battery charged? Use the charger and cable that came with the device and leave it on the charger for an hour or so and try again.

This will work even if the device is powered off. Of course, you will need power for it to work. Have you tried to plug the device into a power outlet. Should get around a battery problem.

Force power down if the above give you trouble.

Hold down both the Sleep/Wake button and the Home button. Ten seconds or more. Hold until the Apple logo appears.

more details on re-booting:

http://ipad.about.com/od/iPad_Guide/ss/How-To-Reboot-Your-iPad-Power-Off.htm

See iPad 2 crashing after 8.3 update