DFDR on MEL...

[Mitch Cronin]

Was about to head out for some high power runs after an engine change the other day and began to wonder out loud whether there'd be any trouble doing so with our DFDR missing.... and was absolutely amazed when someone pointed out that it's in the MEL ...

Then I came to wonder: Just because it's legal to go without the thing, does that mean pilots would do so?

What say you folks??

edited to add... it's in our A320 MEL, I haven't yet looked for other ships.

[Tango Foxtrot]

Mitch;

Deferrable on the -8 and RJ. Three days as long as the CVR works. How would a U/S DFDR affect the safety of an A/C? And yes on the rare occasion when DFDR is U/S, the A/C goes flying. I often see MELs questioned, but have never heard of anyone refusing an A/C because DFDR is U/S, or not there.

That's the way it is where I am.

Tony!

[Canus Chinookus]

If the MEL says I can go, I go.

[Mitch Cronin]

Interesting.... Niether of you so far are thinking as I had guessed you might.... OK, so the book says go, (yep, providing the CVR is working and it must be fixed within three days)... however... if the kadiddle goes for a flammy and there ain't no DFDR to record it, and as a result someone winds up putting the bird into a whoa-dang.... who's to say who didn't screw up???

Or.... in a worst case scenario.... heaven forbid... we wind up shovelling the bits of what once was an airplane out of the muck some place.... and all we have is the sound of "oh damn!" on the CVR.... Who do you suppose will wind up being blamed for the result, without a DFDR readout to tell the whole story?

I'm surprised the regulators would allow it.... and I'm even more surprised to see pilots allow it. The likelihood of any airplane hitting the dirt is slim (thank goodness!) anyway... so the likelihood of one with the DFDR on MEL digging a big hole is rediculously remote, but to allow for the possibility.... it seems to me like saying:

released as per MEL blahblahblah, if this one goes bad we'll never know why, so we can put all the blame on the pilot. (or wherever we like)

[Specs]

Well.....If things go wonky then it's obvious the missing DFDR affected the W&B and that's the cause right there. sheesh

[Southshore]

So much of life is statistics, in other words, managed risk. TC says, (and the insurance industry) for the large part, flying is immensely safe. This is the same reasoning behind 2 engine offshore stuff. You can reasonably expect to go 3 (or whatever number of) days without a critical incident. That's the thinking. No? Well, the other rational says that the hardware is gonna get baked anyway. So, there ya go.

[Specs]

I seem to recall reading somewhere that we're (the industry) not to far away from real time downloading of data while in flight. It would save a bit of wgt I imagine and preserve data. That would have be useful in light of those incidents where the FDR was either destroyed, unuseable or lost at sea.

Of course what do you do then the xcvr goes inop? Same as you do with a missing fdr I suppose - defer it for a 3 day fix but given the low cost and abundant spares stock of radios, or even on board switching between radios, I'm not so sure they'd allow for a MEL deferral?

[Guest woxof]

If you think it is unsafe to go because the DFDR is U/S, what about all the other things in the MEL. AS a passenger which plane would you rather fly on. The one with no FDR or the one with a reverser locked out? You are being unrealistic.

[Guest Kilo Mike]

On a different slant; A question to ask is how many deferals would you be willing to accept?

I have my limit ... Do you have your own? I sometimes don't care if it's deferable by the MEL. Once my limit is reached, she's going to the barn.

[Spinnaker]

What are these MEL things you guys are talking about? I never see them... how about you Canus?

[boestar]

WE are limited to 3 MEL. Any more and we need Flight Ops approval to fly it.

B

[Moon The Loon]

Yo Mitch: Some of the others have it right. If it's legal to take, then it gets taken. Look at it from another point of view: the manufacturer says it's safe, the legislator says it's safe, the flight operations VP says it's safe - how do I justify not taking it?

On the other hand as already stated, if sufficient MEL items exist, some can impact on others. For instance on the DH8 we could go with an inop ECU. At the best, this is a major MEL item as it can really mess you up on your approaches if not handled properly (and there's no "book" on proper in this case. Experience provides the technique). If the nose-wheel steering is also inop, then the MEL stated one has too great an impact on the other and you can't go.

Then there are the multiple MEL's without compatibility charts. One then needs to make up one's mind on how one can impact the others before a decision to go/no go is made.

Hope that gives you a little insight from the dark side.

[vanishing point]

As Moon states, there are certain items that can be deferred provided you don't lose certain other items. These are spelled out in the "Supplement Combatibility Chart".

I'll have to look up the FDR. As for not having one working and the flight goes south at some point..........I'm sure they'll be able to piece it together from all the cursing and name-calling on the CVR (in fact I'll make certain of it!)

[Mitch Cronin]

It wasn't from a safety standpoint that I was thinking you might not want to take the thing... Heck, the box only records what is, it can't change anything, so there's zero effect on immediate safety...

I was just thinking from a "for the record" point of view... but then I can see the "why not?" too. In the worst case scenario you wouldn't care anymore, and if anything less than that worst case should happen to occur the world will just have to take your word for what happened.

Cheers gents.

Mitch