View Full Version : BATTERY LIFE

12th May 2006, 11:19
Could anybody please tell me what is the minimum battery life required for certification purposes when one has total generator or alternator failure on an IFR aircraft and what this time is based on.

1. Light Twin.

2. Jet Aircraft with inoperative APU & RAT.

If somebody could quote the relevant regulations either Aussie or UK would be helpfull.

12th May 2006, 13:41
Can't point you to the appropriate regulations on the design certification, but I'm under the impression that you must have 30mins minimum in the event of a complete electrical system failure.

12th May 2006, 13:51
.. and, in your next sim session .. ask to have a look at a double genny failure (or whatever it takes on your bird to end up on standby DC power) shortly after takeoff ... conditions ..

(a) severe IMC

(b) a bit of terrain gently stirred into the mixture

(c) and then have the backseater sit on his hands .. reposition to the ILS defeats the whole point of the exercise ..

.. and then see just how quickly the battery life evaporates ..

I used always to give this to endorsement crews in training ... the number of pilots who were quite used to the failure-position reset routine was near 100 percent ... the number who had severe adrenaline responses during the early part of the recovery letdown was significant .. instant converts.

A useful Oz reference (http://www.casa.gov.au/rules/1998casr/021/021c38.pdf)

12th May 2006, 21:25

You asked about the regulatory information in the UK, the current regulations are in the main EASA Certification Specifications, see the link for detail.


For aircraft below 5700kg, with some exceptions, the UK CAA mandates a specification which you can find on their website in:-

CAP 747 Mandatory Requirements for Airworthiness. The specific detail can be found on their website in the Publications section. Look in the publication at, quoting from memory here, the Appendices, Generic Requirement 4.

Happy reading.:hmm: