View Full Version : Obstacle or standart srategy

1st Jan 2010, 18:29
What strategy would you prefer in case of engine failure over mountainous area with a MORA 20000, max FL for standart strategy is 220? A320 NONETOPS.


2nd Jan 2010, 00:36
No strategy?:}

2nd Jan 2010, 09:17
Hi Boroda,

2,000 feet clearance sounds too close for my comfort (effect of winds etc.). So I'd opt for Obstacle Strategy in the hope that I'd be away from the 20,000 MORA, or I'd have used a bit more fuel so my ceiling was higher than 22,000 feet.

2nd Jan 2010, 11:29
Accepted. But if the clearence is rather enough to compensate all the effects? Isn't it better use standart strategy to land more quickly, to run the remaining engine at possily lower thrust for shorter time? What the reason could it be to hover at green dot for long time in such situation? I ask because there is an opinion in our company to use obstacle strategy whenever you are over area with MORA above 10000 - I don't understand the necessety:ugh: I accept it only in exeptional cases when mountains are higher then our maximum possible level for any strategy or near it.

2nd Jan 2010, 13:01
Our company SOP is the obstacle clearance strategy as well. Be aware of any escape routes or decision points (such as those published when routing over the alps). The latter will be of more importance in the case of an explosive decompression, fire etc and/or an inability to maintain alitutude above the MSA/grid MORA - again not an issue on the A320 but will be on a heavy A321.

Getting down quickly and reducing the time on the remaining engine doesn't really feature in anything I have read for anything other than things like fires or decompression. Of course if you have reason to believe that the live donkey will go out (fuel contamination as an example) then I can see your logic for getting on terra firma quick. But generally in our airline we like to take things nice and slow. The obstacle clearance strategy will give you plenty of time to get on oxygen (if necessary), establish comms, work out who has control, carry out ecam procedures in an unhurried manner, get a call into ATC etc etc. If you have any doubts about your terrain clearance then get ATC to give you a vector to somewhere safe and back it up by checking against the enroute charts.

Finally the engines are rated for MCT for as long as you have enough fuel to feed them so I wouldn't be particularly worried about the live donkey unless as I noted above you had reason to believe that whatever caused you to lose the 1st one is about to raise its ugly head again.

2nd Jan 2010, 14:54
I accept it only in exeptional cases when mountains are higher then our maximum possible level for any strategy or near it.
Surely if neither scenario would suffice you do not fly over such area at all?

FD (the un-real)

2nd Jan 2010, 15:52

of course, you are right

No way do I want to hurry procedure or do it more complex (thus reducing safety level) or fly between stones. But when I obviously above them there is no difference from our pilots point of accomplishing procedure exept for setting another speed, speed that is greater than green dot, that is almost minimum.

Spasibo for your opinions

2nd Jan 2010, 16:24
I tend to imagine the eng out scenario cruising over FL300, but it can happen during the climb, at 9.000, for instance. Then the strategy to adopt is really important.
In the cruise, you are suposed to be able to fly 2,000 higher than any obstacle, so no need for an obstacle strategy, no need to fly slow. Otherwise you would have to determine decision point/s and/or escape routes and fly the obstacle clearance strategy in the event of an eng fail and then go, turn back or divert to a escape route, as appropriate.
So my view of this is: if there are no decision points nor escape routes determined for the route segment being flown jusf follow standard strategy. If there are decision points, follow obstacle strategy untill clear of them, then standard.

Kirks gusset
2nd Jan 2010, 18:54
2000 ft clear of the flight planned route or 1000 ft clear en-route to an airfield at which a landing can be made. There is no options, if you need to keep high, use the obstacle strategy, if not std. The winds over high terrain effect the MORA, as does temp, so this is already taken into account when drifting down by the "advanced situational awarness of the crew" There is no rush, this is a drift down to stability, initially setting green dot or min clean plus MCT will buy you time and altitude, unless there is a reason to get down early, like single pack or APU capability, there is plenty of time to revisit the option.

2nd Jan 2010, 19:18
In Canada we have PC12 aircraft, with pasengers, at night, IFR over some very high rocks and hostile real estate, their driftdown will be making the front page any day now, already had a Ceesna 208 fatal crash under these circumstances, the line between stupid and brave is getting a bit fuzzy methinks.!

3rd Jan 2010, 14:44
So my view of this is: if there are no decision points nor escape routes determined for the route segment being flown jusf follow standard strategy. If there are decision points, follow obstacle strategy untill clear of them, then standard.:}

My view is this: if there are no decision points or escape routes determined for the route segment being flown it is completely safe to use obstacle strategy. If there are decision points or routes, obedience to whichever strategy or combination of was used to calculated those routes is vital to stay withing desired goals for all of a) obstacle clearance b) endurance c) oxy levels. Even if it means using Fixed Speed strategy over high terrain which of course is completely safe as long as margins between granite and net ceiling are due. Of course, don't forget the ISA and Anti-Ice.

FD (the un-real)

3rd Jan 2010, 19:43
Even easier:

-No MEAs above EO MAX FL: standard strategy

-MEAs above it: obstacle strategy plus decision: go, turn back or escape route

Bruce Waddington
4th Jan 2010, 02:56

Even easier yet,

Always start with the 'obstacle' strategy. Once the heart has calmed and the Drills, ECAM, and /or checklists are complete evaluate your situation and adjust the descent profile as required.

best regards,

Bruce Waddington

4th Jan 2010, 08:43
I agree.

The "heart rate overspeed.... reduce" is one of the first procedure lines to carry out, along with "wait, don't touch anything yet!"

Anyway, we should be familiar the MEAs below us during flight dispatch. I do in every flight. And now, in glass cockpits we have those MORAs and EGPWS terrain display.

In a flight from London to Antalya (Turkey) most of the flight I would do standard strategy without hesitation. But over Turkey, I would do obstacle without hesitating either.


4th Jan 2010, 10:50
Hello, Boroda! for your case you may use standart strategy without any doubt.
1.So the MORA already includes 2000' clearance + another 2000' over the MORA. So you will have 4000' over the highest mountain peak, even if you have instrument error due to the strong wind the clearance is well.
2. from another hand the standart strategy (as it have been said by you) decreases the time spend in the air with one engine operative.
3. drifting down from FL350 to FL220 will cover 100nm, I guess that is rather good to reach lower MORA.
P.S.: don't forget about another strategies as you fly over post soviet region.
con respecto!