AF B772, GPWS averts CFIT
 

I'd like to know some opinion about this incident (post retrieved by www.avherald.com)

An Air France Boeing 777-200, registration F-GSPG performing flight AF-953 from Malabo (Equatorial Guinea) to Douala (Cameroon) with 37 people on board, was en route to Douala maintaining FL090 when the crew requested and was cleared to deviate north of the assigned route due to thunderstorms. Later, while turning right towards Douala the EGPWS of the aircraft issued a terrain warning and called "PULL UP!" which the crew complied with climbing the aircraft to FL130, where the EGPWS stopped the warnings. The aircraft subsequently continued for a safe landing in Douala.

The French BEA reported in their weekly bulletin that the occurrence was rated a serious incident, the French BEA is investigating the serious incident.

My note: MSA there is 15700 ft

Maybe loss of situational awareness being consumed (mentally) by the weather presented?

It's Air France...what more do you need to know...

Are we to believe that the crew of a European National Carrier operating one of the worlds most sophisticated a/c are found bumbling around in IMC with nothing to tell them what the MSA is in their area ? Are AF existing in in some sort of time-warp trapped in the 1950s ? What IS going on with their training division ?

EGPWS has made more saves than we'll ever know about.

Thank you and God's Blessings to Don Bateman and all his colleagues at Honeywell for developing GPWS.

Is this correct?
I find it quite strange. Am I the only one?

was also a story at jacdec.de

Out of interest, why?

I am not a pilot, nor am I familiar with the area. However, looking at google maps I can see that it is a short hop and, depending on runways in use, the majority portion of the flight is over water. A visual approach on Douala's easterly runway from the direction of Malabo would not constitute a problem flying at FL090. The problem presumably arose from the wx deviation and a possible loss of situational awareness.

A 777 maintaining 9000 ft where the MSA is almost 16000?
Not an airline pilot, so what am I missing here?
Is that the normal SID profile for that departure?

I guess they were also helped by some probably awesome climb performance of a 777-200 with only 37 people aboard.

DirtyProp, check google maps. See for yourself. The MSA applies to certain areas around Douala, otherwise nothing could ever land!

It was almost a full moon that night. I wonder if they climbed into VMC and puckered up a little.

"Out of interest, why?"

Probably, Nigel, for the same reason that many professional pilots find it odd too. I'm sure you know (or should know!) that flying below MSA IMC is only OK under radar or on a procedural cleared route where that level or above is acceptable. To then 'divert' off that route at FL90 without a **** clue where the hard stuff is is OK with you?

AF certainly know how to screw things up! Who are you with?

I think there is a subtle 'gotcha' waiting to trap the unwary. You fly around your regular routes and airfields and have a feeling for what's underneath you. Often, especially in B777, you will be at a major radar airfield. Thus you fly the magenta line & radar vectors and do not have an en-route chart or TMA chart to hand. You've briefed via the STAR chart, but now you debate off the STAR and are lost. It's a consequence of LNAV/MAP displays; and even more with paperless cockpits. OK the charts on on i-pads, but only of you lookout them. Complacency is going to be a killer, and trusting technology to save you is not a healthy attitude. Remember Air Inter at Strasbourg with the EGPWS disconnected. It would have save them, but the company had disconnected it.

Thank you, but I rather check the SID for that airport.
We use Jeppesen charts for flying, not google maps.

While I can't comment on this situation, I find is surprising how many pilots are quite happy to fly out of airports in high terrain with both ND's selected to weather instead of terrain......in the winter when there is no CB's for at least a thousand miles. There is a theory that the terrain display will show when there is a GPWS warning but at some locations, you may not be able to outclimb the mountains especially if an engine is lost. Some like to immediately level off after a problem in these areas as well(at least in the sim) while still headed for terrain.

Now in this case, there is almost certainly weather around but if you are at low altitude in the mountains, you may want to have one display on terrain or at least be checking the terrain once in a while on the other, especially if deviating off the safety of the airway MEA to get around weather.

Perhaps some cooling in the hat would be appropriate. GPWS will warn of gradients of terrain,with comparisons of closing speed. So a sudden change of direction may pick up the first impressions,until the computing element can decide the rate of gradual approachment to a perceived threat. It will give indications,based on it,s own programmed limits. It does not mean that pilots are not aware of,where they are. They simply record that GPWS warning came to us here. It,s a common practice to react in Gpws false warnings. Most common Practice is to do what it wants You to do,so i guess this was the case.You will be safe,then. (from the upper floors and eager reporters,too) I have had many of those,some for reminders,and most for just seeing the limits of the system. -and for pilots today, EGPWS is beyond my time in cockpits,so maybe someone would like to tell about that gadget,to ease also the minds of any interested,in here.

@Naali quote in part "GPWS will warn of gradients of terrain,with comparisons of closing speed. So a sudden change of direction may pick up the first impressions,until the computing element can decide the rate of gradual approachment to a perceived threat. It will give indications,based on it,s own programmed limits. It does not mean that pilots are not aware of,where they are. They simply record that GPWS warning came to us here. It,s a common practice to react in Gpws false warnings. Most common Practice is to do what it wants You to do,so i guess this was the case.You will be safe,then. (from the upper floors and eager reporters,too) I have had many of those,some for reminders,and most for just seeing the limits of the system. -and for pilots today, EGPWS is beyond my time in cockpits,so maybe someone would like to tell about that gadget,to ease also the minds of any interested,in here."

There are many enhancements introduced by EGPWS compared to GPWS. Two key ones are that altimetry, terrain database and navigation position are combined to provide "predictive" alerts of threatening terrain ahead and a color-coded terrain awareness display that provides important situational information about the surrounding terrain with respect to altitude and location.

Those seeking information or unfamiliar with EGPWS might start here: https://aerospace.honeywell.com/en/p...FQwPaQodKmAAdA

Ps. JammedStab I think that we had a good procedure of mostly having the different display on both. Seen couple of times how they can disagree at Tkof mode. The spare Horizon is not there for nothing...

Not much of a pilot if you're using the SID for an arrival!

Groucho The question was why they were "cruising" at FL90. My question was why is that determined to be "strange" and I asked why?

Yes - there are rules for flying below MSA, and I am not saying those rules were followed when they deviated. But that was not the question.

So I ask you, as a stated professional pilot, what cruising FL you would expect / choose / fly / could achieve in a widebody with a sector length of ~60NM?

And I also ask you, how and where has it been stated that the route, as planned, had an MSA of >FL90?

Did the crew climb until the warnings stopped or until they made MSA? I read somewhere that EGPWS warnings stop by design before a safe level off can be achieved.

The French BEA would do us all a favour by ensuring that airline training departments and pilots take EGPWS warnings seriously by vigorously & correctly flying the escape manoeuvre - that is, climb until at least MSA.

Did the aircraft really make a "safe landing" or was it just dumb luck, or Providence, that there wasn't a CFIT as the disoriented crew levelled off below MSA?

If EGPWS saved them, were they not looking at their ND.....or did they have not have the brightness turned up?

Shooting down people involved in accidents or incidents seems to have become the favorite passtime here.

If you know a bit the place you wil find that both airports are at sea level, the whole route is above sea. For a roughly 50 NM leg going easbound, FL90 is a good and correct level . No high MSA in there.

How about this ( speculation )
You take off , take course 060 and find a CB in the middle of the route, you are 3 in the cockpit , you look at the Wx radar , discuss it, and decide to go left. How long you wander left and why unoticed for so long is most probably the issue.
Because when you are clear of the Wx and decide to turn right back to DLA , bingo the EGPWS wakes you up and you find out there is Mt Cameroon in between.

Now a bit of pontification to the Non-pros here :
Because you are profesional you make a report of this to avoid others to make a similar mistake, and your airline, passes it on to the Investigation Board, which, because it is professional organisation publishes it so that other operators can learn from this and avoid it too.

Another possible scenario, Eastern 401 L-1011 in Everglades .

Every professional will read the report in a few months and the system will probably be a little safer as whole.

Throwing stones at people/airlines /countries will set us back 40 years, where nothing "embarassing" was ever reported.

So keep it cool guys, it is good to have reports like this.

Yes, I was under the impression that the plane was departing and not arriving.
Better not fly with me...

Best post in a long time ATC Watcher. Thank you!

Correct, and which is what Nigel and myself were saying all along. As for the rest of your post ATC Watcher, you're bang on. Even though not a pilot myself I get frustrated by the idiotic reactions we often see here on this forum by people who PRETEND to be pilots and spout utter and absolute rubbish.

Having previous experience in this part of the world, it is easy to see how this could happen. A 60nm sector in this aircraft will take about 15mins from wheels up to wheels down. If you add all of the flight deck procedures that need to be done to configure, you are a busy body. Now add to this unhelpful ATC, broken Nav Aids, and the worst weather you are likely to encounter anywhere in the world, the mixture becomes even more difficult. Bearing in mind, flying into a CB that extends up to 60,000ft will have the same effect as flying into Mt Cameroon, and with these airbourne mountains covering much of your sky, your attention may be drawn to the radar display at this point. I think for any pilot that has not experienced this area of operation should not be so critical of this crew. The installed system worked as designed - a disaster was averted - and we can all learn from this.

double post.

EGPWS is a back up system. Terrain awareness/altitude awareness is a basic of instrument flying. MEA/MOCA/MSA/Grid MORA. If you're not on a printed line (MEA/SID/STAR altitude restrictions) it's up to the crew to decide if MSA protection is provided(ie above MSA for the portion of the MSA circle that you're in). If MEA or MSA protection isn't guaranteed, and basic terrain awareness isn't available(terrain chart/minimum radar vectoring chart), then you need to operate above the grid MORA.


Yes, the system, because of the backup safety system, worked. It's not supposed to rely on the backup system. There's a reason why a EGPWS alert is usually a mandatory reporting event, because it's not supposed to happen in the first place.

I remember a case where a 737 crew recieved a GPWS alert around FL100 during an approach in bad weathher in a mountainous region. They zoomed up to FL200+ until the alarm eventually silenced.
The investigation showed they where never close to terrain and attibuted the alarm to hail.

DJ77
In IMC you act on GPWS warning. When out of the warning condition, then you start analyzing. You don't have time to think that it might be wrong, because if it comes on and if it's wright, you're not where you think you are.

GPWS (pre EGPWS) -

After making a crossing restriction the midnight crew accelerated for a high speed climb. GPWS - Terr....Pull... Both radar altimeters flash to below 200' and just as quickly the radar altimeters go away. So the crew thinks they've got a maintenance write up.

That morning the FO starts looking at terrain maps ... "And that's when I started shaking..."

Seconded!
We always need to be reminded of other people's 'nearlys' :ooh:

Misd:

AAL 965, the 757 CFIT near Cali, Colombia, was also equipped with plain old GPWS. There was an informal consensus that had they retracted the spoilers immediately upon hearing the first "Whop! Whop! Pull Up!" put the throttles to the stops, while rotating, they may very well had cleared the ridge-line.

But, had that happened, it was problematic what their subsequent action would have been, for there was higher terrain to the left and straight-ahead. A climbing turn to the west would have worked, though.

That was the accident that resulted in EGPWS.

@ Miraculix. You missed my point.

In this thread most posts (including the title) assume a priori that a CFIT has been averted close to Mt Cameroon. Very possibly it may be what happenned but, please, let's not anticipate and draw definitive and patronizing conclusions (as usual on R&N) before the real story is known.

DJ77

Sorry if I misunderstood you and yes you're right, lets not jump to any conclusions regarding the cause of the GPW that was reacted upon.

I placed a graphic snippet from Sky Vector on one of the STARs. Note also the MSA note.

http://i201.photobucket.com/albums/a...psgstmzkey.jpg