Spanair accident at Madrid

[NigelOnDraft]

Would this accident have occured with a fully functioning TOWS but RAT heater CB pulled?

The answer is NO it wouldn't.

Disagree Posts above show occasions where TOWS have been ignored.

2 systems seem to have "failed". One was deployment of Flaps. One was TOWS. One is critical, one is supplementary...

If the Flaps don't get deployed, we have a major system / SOP failure. TOWS is a supplementary system designed to "trap" the first failure, and usually would do. However, we cannot rely on it doing so, nor blame the TOWS for the accident. Even if the TOWS had been tested, it might have had a failure mode that allowed it to say it passed, and/or failed later on.

The recommendations of the inquiry, need IMHO, to 90%+ concentrate on stopping an aircraft getting to a takeoff roll without Flaps deployed. If an aircraft starts rolling, then aborts due no Flaps + TOWS - that is not the safety system working "correctly". It just a **** lucky near accident

NoD

[forget]

Here we go again. Lets get the facts right. NO CB WAS PULLED WHICH AFFECTED THE TOWS

Please point out where this has ever been said

that a CB was pulled which affected the TOWS.

AFAIK only 1 CB got pulled - the one for the RAT Heater, and the RAT Heater alone... so I for one believe it has been said repeatedly.

The two statements do not tally. Pulling the RAT Heater CB did not, does not, and cannot, affect the TOWS in any way.

[justme69]

Just for clarification, there have been several accidents of this type where slightly different reasons have led to similar consecuences.

-There have been cases where a perfectly serviceable TOWS was disconnected by a "human" pulling a c/b (MAP case in Lanzarote).

-There have been cases where a (electrically) "working" TOWS has not been activated due to a bad switch in the thrust handles (727's like in Delta Dallas accident or 737 in DCA incident). In those cases, a theoretical "lighted indicator" that would've signaled the TOWS was powered on the ground would've given the false sense of security that the TOWS was working, when it actually wasn't for practical purposes.

Even worse, in Dallas case, the switch was determined to work "some times", perhaps once every 2 or 3 actuations, so checking the TOWS would've only LIKELY, but not for sure, have detected the malfunction. Neither an "operating" lighted TOWS indicator nor a test are 100% effective measures to know the TOWS won't fail when it's needed. The most effective measure given current designs is the test shortly before each takeoff, though, as it would most likely catch an inop TOWS on time. The pilots are not going to be staring at a lighted TOWS indicator to see if it's on while they take off. And having it "on" doesn't mean the TOWS will work if the switch in the handle is broken or if the loudspeaker is blown, i.e. Only chance of catching it is to test it and pray it doesn't fail from that time until the time it's needed.

(Incidently, in Dallas Delta accident, i.e., the crew answered the checklist FLAPS/SLATS as the correct "15/15/Green light" while the FDR and the CVR showed no indications that they ever moved the handle nor did they really had appropiate time to have done it as they moved to the next item in a like less than a second. So paying "lip service" to checklists is a long known fact.)

-There have been cases where the TOWS failed for undetermined reasons (Northwest in Detroit).

-There have been cases where (probably) the TOWS failed due to part of the ground/air logic circuit failure (Spanair).

-There have been cases where the TOWS worked just fine but the crew failed to take appropiate action (LAPA).

-There have been cases of accidents with victims where it wasn't clearly reported why or if the TOWS failed (Lufthansa in Nairobi or India Air in Hyderabad).

But the short story is: quite a few airplanes have tried to take off with incorrect configurations, when procedures, training and aircraft indicators (flaps/slats panel indicators) should've made it clear that this wasn't a good idea. Most of them have been "saved" by the TOWS. Of the rest, most have crashed and some have saved the day one way or another (quick command of flaps, reducing angle of attack and flying ground effect, aerodynamics conditions allowing for clean takeoff with little performance penalties, etc).

But we come back to quite common even nowadays scenarios of landings with gear retracted (forgotten, usually on small private planes, but even recently in small and even some large airliners), spoilers in the wrong setting, or similar events. They range from simple oversights to configuration alarms being turned off by the crew while dealing with another malfunction that made them distracted.

A 100% reliable TOWS is not "impossible", but it's probably not "worth the time and effort". Such a design and expense is probably better use on other, more vital systems. But a much better design is certainly possible, one that is close to 100% effective and today's technology should make it more than cheap enough to be considered. So why not?

But the main reason for these accidents, crew failure to perform vital actions for which they were trained and under not overly-stressful circunstances (well rested, before a takeoff, plenty of time to double check on 20 minutes long taxiing... some of you would simplify it as "pilots simply screwed up"), will not really be solved, only "masked" by the more effective TOWS.

[lomapaseo]

It was determined by the regulators that the system should be checked prior to each flight. However that gets in the way of making a profit so some operators drop it down to first flight of the day only.

Are you sure that there are facts supporting this hypothesis?

Do you have anything other than supposition to support this?

[grumpyoldgeek]

It's time to wake up. Commercialism and its supporters will kill this industry.

I thought they (and a healthy dose of government subsidy) built the industry.

[bubbers44]

The TOWS check takes 10 seconds. Usually during push back. It would not slow down operations at all. Yes, the TOWS would not be required if pilots did their checklsts properly. I always thought if I really did the checklist nothing should be a problem. Just responding to the checklist is another matter that is easy to fall in to. We get bored and keep repeating the same checklists and sometimes just say the words. That is where the problem lies. Saying the response then looking at the actual position. Usually you realise the mistake but the checklist reader may assume what you said was true if he did not verify. Humans are prone to get complacent when doing the same thing over and over.

[el #]

Originally Posted by NigelOnDraft

2 systems seem to have "failed". One was deployment of Flaps. One was TOWS. One is critical, one is supplementary...

Sorry NOD, but if you use words as above, that is the same ambiguity present in the preliminary report and various press pieces.

1) The flap system has NOT FAILED. evidence so far suggests that pilots have NOT set flaps.

2) The TOWS system HAS FAILED. Due to R2-5 malfunction,

3) Maintenance has FAILED to detect and address (2).

Regarding the comment about 90% of engineers would have done (3) same as in Madrid. I have a problem in believing so, but if it's true that makes me happy that I'm not a Pilot and I don't fly that often after all.

All the rest I agree with you.

[NigelOnDraft]

el #

1) The flap system has NOT FAILED. evidence so far suggests that pilots have NOT set flaps.

Agreed, but I did clarify it with:

If the Flaps don't get deployed, we have a major system / SOP failure.

Re the Engineers, I am afraid that is my observation, with quite a few years of Airline Ops, a good number as Capt - and increasingly so. Defect in book (e.g. an ECAM Message), ECAM Message in MEL cross refers to MEL procedure, MEL actioned PDQ, or if "No Maint Actions required" then Flt Crew expected to accept it under ACF.

It is the MEL sections, under the above scenario, that are supposed to "trap" insidious deeper problems...

I am not saying that the Spanish / Spanair / MD-80 philosophy is the same since I work under a different authority / airline / type(s). But I am saying that from my experience, the apparent chain of events as far as the RAT Heater / Engineering actions went, is much as I would expect, and certainly not enough as far as those individuals were concerned to have been e.g. negligent enough to carry any responsibility in law.

NoD

[FlyGooseFly!]

Blubbers44 posted :-

Just responding to the checklist is another matter that is easy to fall in to. We get bored and keep repeating the same checklists and sometimes just say the words. That is where the problem lies. Saying the response then looking at the actual position. Usually you realise the mistake but the checklist reader may assume what you said was true if he did not verify. Humans are prone to get complacent when doing the same thing over and over.

Once upon a time I thought I had engaged and involved four other people in a calculation - fortunately one with a non-fatal outcome - when it turned out to be incorrect I remonstrated at length only to be told - "Oh, we heard what you said but we didn't bother to actually work it out because we thought YOU knew what you were doing!"

[GXER]

forget said:

When the MD-80 RAT Heat MEL was written up it allowed flight with no forecast icing conditions. Simple, and no problem so far. Pull the RAT Heater circuit breaker and off you go. Crucially, what wasn’t considered by the MEL writers was why the RAT might Heat on Ground. A failure of Relay R2-5 (Flight Mode) would do it – which would also disable the TOWS. So, pull the RAT Heat circuit breaker, RAT Heat problem fixed, TOWS is now inop with NO indication of failure. And I defy any line engineer, no matter how smart, to raise his hand and say “Hold on guys, RAT Heat on, I bet R2-5s failed and we can’t just pull the RAT breaker because the TOWS might also be inop”. That’s down to the MEL actions and, from what I’ve seen in this case, they ain’t up to the job.

This accident has been waiting to happen from the day the aircraft left Long Beach. Very poor TOWS/Flight/Ground logic design, and very poorly written MEL.

Purely from logic perspective - the conclusions (a) that MEL writers did not consider why RAT might heat on ground and (b) that the MEL was poorly written is not justified by your argument you present, unless the MEL actually contemplates the scenario of the RAT heat operating when air/ground logic dictates that it should NOT be operating. If the MEL merely states that flight is permitted with RAT heat inoperative (for whatever reason) in certain circumstances (no icing forecast), then the MEL did the job it was designed to do. Of course it is possible to argue that it should do more - but that's another issue.

[sevenstrokeroll]

communication on the internet forum is imprecise...

yikes

we are pilots talking to pilots...sometimes we are cryptic, it is our way.

we use one word that covers many in radio work.

we chat on this forum as if we were in the ''ready room'' talking things over with our fellows.

I don't always agree with Nigel, but I wouldn't point at his posts as imprecise.

when we don't understand, we should ask questions...say again



Someone indicated that when the airlines were regulated we had more plane crashes...true. But we have more safety gadgets now, more experience and we shouldn't be repeating accidents from 20 years ago.

30 years ago the US airline industry was deregulated. IF it had remained regulated, adding new safety gadgets to the cost of a ticket, things might even have been safer.

cryptically yours

sevenstrokeroll

[sevenstrokeroll]

imagine

imagine if another plane had been right behind the doomed flight? imagine if one of the pilots behind the doomed plane noticed that the flaps/slats were not extended.

imagine if that pilot didn't radio a warning prior to taking the runway?

imagine if that pilot DID radio a warning?


WE are our brother's keeper. Keep your eyes open for the problems of others...and after you check their plane out for problems...CHECK YOUR OWN PLANE ONE MORE TIME. (or like count basie, ''april in paris'' one more once)

[TyroPicard]

MEL precision...
You may fly with RAT probe heat INOP.
The RAT heat is on on the ground, when it should be off.
The fault is not in the RAT heat, it is in the system that auto-controls it, so a different MEL item may apply. But the RAT heat is not INOP.
Simple, innit.

[Joetom]

Defect. "One nav light inop on left wing tip"

Action. "Crew will not accept MEL, so new bulb fitted, still inop"

Aircraft N/stopped and crew and passengers to hotels.

Working party on route to troubleshoot and fix inop nav light.

This appears to be the way some see things going.

One point has crossed my mind, this MEL item may of been used many many times in the past for the same said pilot reported defect, when defect was fixed by changing a relay, did no alarm bells get sounded !

[BOAC]

It is indeed a sobering thought, NoD, that if the crew HAD tested the TOWS as per the apparent manufacturer's rec., before the return to stand, things could well have been different.

[lomapaseo]

It is indeed a sobering thought, ..., that if the crew HAD tested the TOWS as per the apparent manufacturer's rec., before the return to stand, things could well have been different.

It's going to be interesting in the timing of this kind of test. Just how often and when?

Should it be in the takeoff checklist right before the crew call out green green for the flaps/slats. If not is there a chance that someday a crew does the check on taxi out then aborts the takeoff for any reason goes back to the stand and some maintainence function mistakenly disables the TOWS.

It's not easy to pick out the best solution without data and analysis of the Pro and Cons

[sevenstrokeroll]

whenever mx does work in the cockpit, we have to do an ''originating' checklist...meaning first flight of the day.

whenever I got into the cockpit, I checked that the engines were not running and then I moved the throttles, got the warning and pulled them back.

it takes less time than it takes to type.

[atceng]

circuit breakers

The information came from a block diag and from post #2003, mermoz92,although they refer to the possibility that breakers feeding the RAT heater breaker may have been switched of as per maint man to ensure isolation.If these were not reset other functions would be unpowered including tows.
I must try to read your Graph thoroughly after assembling the tiles,to see if it is possible to establish if RL2-5 was faulty or if alternatively there is any evidence that the sensor logic feeding the relay was erroneously causing it to be de-energized.
Apologies to the winged fraternity for boring technicalities.

[justme69]

For that and other reasons I do not believe at all it was for "commercial reasons" that some airlines (not only Spanair) "stuck" to the original McDonell recommendation of checking TOWS in the first flight of the day and then whenever pilots entered a "new" cockpit or where absent from an "old" one for a long time.

They know TOWS don't fail that often nor are they too hard or expensive to fix (relatively quite a simple system).

They know it SAVES them money. They know it only takes 2 seconds to test them.

But somewhere, the person translating/writing the SOPs for Spanair (and other airliners) never heard of Boeing LATER recommendations to change that to "check the TOWS before each and every takeoff-period".

Nor did the FAA or EASA or any other regulatory body in the world make such a recommendation mandatory.

I'm pretty sure should there have been better communication between Boeing and Spanair (or the other operators which SOPs still didn't include the updated procedure), I'm pretty sure it would've been adopted.

In fact, Spanair adopted it a few days after the accident, before any recommendations or directives were out.

I do not know what communication channel failed there. I don't know if it is each individual airline job to constantly bombard Boeing with:
-"Have you changed anything from our SOP"?
-"Have you changed anything from our SOP"?
-"Have you changed anything from our SOP"?

Or if it is Boeing's job to query each operator flying their airplanes:
-"Have you included recommendation update YYY-XXX?"
-"Have you included recommendation update XXX-YYZ?"
-"Have you included recommendation update AAA-BBB?"

Or if all Boeing has to do is fax EASA/FAA/each country's authority and say:
"Remember procedure XXX-XXX? Well, it was wrong. We found a better one. Please tell everybody to use YYY-ZZZZ instead. This is the only communication we will send out."

And then pass the ball to each country regulatory body to oversee the update and compliance.

Spanair claims they were never told about the update in procedure and therefore never included it. Their SOPs were the ones they thought were recommended by the manufacturer and approved by Spanish and European regulatory agencies and of course would've passed FAA ones too. Other airliners flying at the time in Europe used the same standard procedure.

So who do we "blame"? Obviously all of them have some "fault" in the subject, but who is the main culprit? The way it is now, it seems they all thought they were doing the right thing. Except, maybe, Aviación Civil or perhaps FAA/EASA?

[justme69]

Oh, no, I understand the recommendation.

I also know the first one was made AFTER the accident in Detroit, and it was not the original, approved procedure.

I also know that many operators claim they NEVER WERE NOTIFIED of the recommendation. Plenty of them flying around up until very recently. As you very well say, for over 20 years since it was made.

I know Boeing CLAIMS they notified it to all operators that AT THAT TIME were using MD-80's. I also know that Spanair (and others) didn't exist at that time and started their operations AFTER the recommendation was sent out.

I'm also curious if Boeing recommended individual types, or better yet, ALL their planes, not only those with a generic "similar TOWS design" referring to the MD-80 series (other types have suffered similar accidents/incidents).

I wanted to know how it was possible that Spanair "inherited" an approved SOP that didn't include it and, apparently, nobody told them.

And why this recommendation wasn't "approved" and mandated by the FAA or ANY similar international bodies at all.

Until a week ago.