Bird Strike Detector for Jets??

I began working on the 767 electrical power systems shortly after this incident. There were a number of systems that were discovered to have been left off the standby power system (the barry power).

We also ran into a problem in that the system incorporated a static inverter with a 1 kVA rated output. The original design had only utilized about 50% of its capacity. Unfortunately, its rating had been specified assuming linear loads. While the Boeing specs limited the current THD any load was allowed to draw, loads of less that 200 VA were exempt. And most of the loads supplied by the inverter were small and of the non linear variety (power supplies mostly) with up to 30% current THD.

After the Gimli incident, the missing bits were moved on to the inverter bus, whereupon the inverter refused to produce an output voltage within spec. The loads were taken back off. Since my responsibility only extended to the power system, when I asked where the loads were put, I was told to shut up and mind my own business.

Sloman would have told them to strap extra batteries to the bottom of the plane, and Dimbulb would have signed off on it.

Battery capacity wasn't the issue. Static inverter capacity (particularly derated for nonlinear loads) was.

British Airways (I believe) ordered an option to transfer DC loads over to the APU start battery as well as the primary standby battery. That provides some additional 24 Vdc capacity.

Wow, friendly. Were you working for Boeing directly, or for one of their subs?

Would doubling the VA rating have helped?

And, are the batteries changed out periodically? (They wouldn't happen to be lead-acid, would they?)

Michael

Directly. That was when they still did some engineering in-house. But no more.

The proper solution(s) (which we implemented on the 747-400 and on) were: To spec a new static inverter capable of supplying nonlinear load currents, and to remove the exemption on power quality for smaller loads.

There is an involved maintenance procedure for the batteries. And they are wet cell NiCad, 24V 40 Ah.

One of my more interesting projects was doing an analysis for a failure mode where the battery charger gets 'stuck' in constant current mode and electrolyzes most of its water, producing H2 gas. Its basically a problem in electrochemistry. Since most chem data is in CGS units, that's what I used for the analysis (the desired result was a percentage H2 concentration in air, so it really didn't matter). When I submitted the results, my boss started throwing a fit about how Boeing simply didn't used metric units. I didn't want to introduce the possibility of an error due to units conversion, so if he wanted it re-done in furlongs per fortnight (yes, that's what I actually said) he could have someone else do it. The document remained as is.

"Wingsuit Life Vest under your seat"?

"In the event of an in-flight emergency your computerized Wingsuit will carry you to safety. Simply don the wingsuit [cue Flight Attendant demonstration] and pull the cord. The wingsuit autopilot will safely land you even if you black out."

Michael

iirc..most crash deaths are from people getting BBQ'd from the burning jet fuel. Or maybe it was asphyxiation from the jet fuel smoke and then BBQ'd.. dunno..

D from BC myrealaddress(at)comic(dot)com BC, Canada Posted to usenet sci.electronics.design

Asphyxiation first sounds more likely.

Michael

Correct. There was a proposal some years ago to equip commercial aircraft with 'smoke hoods'. Basically a clear, high temp plastic bag one would pull over their head and secure with a drawstring. The bag had a permeable patch made up of an activated charcoal filter to allow some air exchange.

The idea was that people still alive after the impact would have a few minutes of breathing air and vision. Although the opacity of smoke is pretty bad, a significant hindrance to vision is its effect on one's eyes. If you can see and breath, your odds of getting out of an aircraft are much better.

The airlines killed the proposal.

Sounds like a 'smoking' hot product idea to put on E*bay.

D from BC myrealaddress(at)comic(dot)com BC, Canada Posted to usenet sci.electronics.design

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Sell them at the airports!

"Not sure about the safety record of XYZ Airlines? Buy a Smoke Hood now, and get a FREE canister of oxygen! Provides 5 minutes of escape air. Only $100! How much is YOUR life worth to you?"

Not O2 canister needed. There's plenty of oxygen in the cabin unless its actually engulfed in flames. What kills you is the buildup of Co2, CO and other noxious gasses. If you can filter those out, you can breath.