24th Feb 2016: EC 135 crash in northern germany

[hueyracer]

I don´t know how autos are taught in the police nowadays (if at all-full autos to the ground are not a requirement any more, as pilots train on MET directly, which alleviates the requirements), but when i learned to fly (in the military), autos were done by looking outside-with the Radar ALT giving you some assistance, but we were not flying relying on them (or even waiting for an audio feed)...

[SilsoeSid]

… at night?

[Spunk]

Easy Sid, not all questions in a forum are meant to be cynical. Sometimes a question is just what it is: a question.
I'm not IFR rated nor do I have any NVG experience (if at all the crew was operating under NVG), consequently I haven't seen too many RAD ALT.
So dear Sid, subject to your approval, may I ask my question once more: does it really make any difference or would a landing light or even a night sun AND looking outside AND / OR a call-out from the Co based on a bar altimeter be more suitable (IF the RAD ALT issue has anything to do with THIS accident at all)?

[MightyGem]

OR a call-out from the Co based on a bar altimeter be more suitable

Not really. Bar Alts have an allowable error of +/- 50ft(IIRC), altimeter settings(in the UK anyway) are based on forecast pressure so may not necessarily give 100% accuracy, plus the co pilot would have to know the height of the ground above the altimeter setting datum and subtract that from the reading on the bar alt to know when they were getting near the ground.

A Rad Alt is far more accurate and gives your height above the ground so no need to be doing sums in a time of high stress.

[SilsoeSid]

So, you take off from the base with the bar alt reading zero, after all it has been said in that area "AGL is more or less MSL".

You're flying around the area, on the way back to base for example, and both engines go quiet ... what is the elevation of the ground below you? 49 feet, 62 feet, or perhaps higher. At what bar alt height would you begin the flare?

The mention of nitesun and rotating landing lights is totally irrelevant as you can bet your bottom dollar that the high load nitesun will be pointing backwards, will take three attempts to spark up from the controller in the back operated by the rear crew member and the rotating landing lamp will be in the wrong place ... and you probably aren't going to start moving that around.

The fixed landing lamp will be pointing in its usual place, which will be handy, however just as it begins to give a bit of ground definition, around the point at which you begin the flare, the ground goes dark again. The next time you see the illuminated ground is when you are cushioning on.

The rad alt will give you a pretty accurate height above the ground/ water/ trees/ rooftops on which to base your plan of action.

[John Eacott]

Sid,

You could surmise with the same degree of authority that the radalt will only show what you are currently passing above, and not the sheer cliff face or group of buildings 50 feet in front of you. The UK use of QFE, against the more widespread use of QNH, can be a limiting factor in this sort of assessment IMO. Flying on QNH from my experience has created a better overall judgement of height above ground if for no other reason that you are always aware that your baralt is referenced to sea level.

And for night ops my steerable searchlight/landing light would either be extended, or if retracted I would know the exact number of seconds to run it out to the optimum position. Just one of those idiosyncrasies that I built up over the years.

Now for the discussion on whether you should flare at the bottom of an IMC or night auto, or pull pitch and run on.

[megan]

Now for the discussion on whether you should flare at the bottom of an IMC or night auto, or pull pitch and run on

What is taught regarding this these days? 50 years ago the navy taught 35 knot run on.

[SilsoeSid]

You could surmise with the same degree of authority that the radalt will only show what you are currently passing above,

Isn't that just the information you need?

and not the sheer cliff face or group of buildings 50 feet in front of you.

... which would be the same cliff or building if your reference was the bar alt.

Flying on QNH from my experience has created a better overall judgement of height above ground if for no other reason that you are always aware that your baralt is referenced to sea level.

Interesting, which is all well and good if you immediately know the elevation of the local terrain below you to the nearest 100ft or so.
The rad alt has to be more useful as it doesn't give you a 'better judgement' of your height above the ground, it tells you.

And for night ops my steerable searchlight/landing light would either be extended, or if retracted I would know the exact number of seconds to run it out to the optimum position. Just one of those idiosyncrasies that I built up over the years.

How many seconds is that John?
I know for the 135 it is 'my 5 seconds' from stowed to the set forward position and then maybe a couple more to move it from the straight ahead position to somewhere more handy. (no control when it is in transition)
Ooops, no steerable LL on doub eng fail

Now for the discussion on whether you should flare at the bottom of an IMC or night auto, or pull pitch and run on.

Join in -
http://www.pprune.org/rotorheads/336...-training.html

[SilsoeSid]

yellowbird135, is this ok?

[John Eacott]

Sid,

If there is rising ground ahead, not seen in the dark, where would be the advantage of a radalt over a baralt? Of course it is more accurate for where you are, but sometimes I'm not sure that your thinking is as lateral as it could be.

The time to extend your landing lamp depends on aircraft type, as does which busbar provides the power. Not all helicopters lose the landing lamp with a double engine failure.

[SilsoeSid]

If there is rising ground ahead, not seen in the dark, where would be the advantage of a radalt over a baralt? Of course it is more accurate for where you are, but sometimes I'm not sure that your thinking is as lateral as it could be.

The advantage of a rad alt over a bar alt in this situation, imho, is that it's going to tell me fairly accurately how high I am over the ground that I am about to attempt the final stage of my engine off landing to.

I don't know about you, but my thinking is that a rad alt will tell me when I'm approaching 500', 200' then 100' and says, 'you know what Sid, best you start moving that thar stick & lever ... rather than a landing lamp giving me just enough info that says, 'well here's the ground Sid, whatcha going to do in the next 3 seconds to get out of this' or a bar alt that says, 'well Sid, if you were over the water you'll be getting wet just about .. now!'

Not all helicopters lose the landing lamp with a double engine failure.

I don't think any do, do they?

[TorqueOfTheDevil]

Agree with Sid's points in the posts above.

In this sad case, there was no building or cliff ahead. They very nearly made it successfully onto the ground. We don't know yet if the RadAlt is a factor in the outcome, but I would suggest that if this crew did have and use the RadAlt information, it was that which allowed one of the crew to survive. If they didn't have it, they might all have survived had they had the information.

Sincere condolences to the families and best of luck to the surviving crew member for his/her recovery.

[Rotate too late]

I echo the sentiments of the previous two posters, I'd also like to congratulate people on a far more professional/mature approach to this tragic incident on this thread. Having observed the Shoreham thread over on the mil forum, some of it quite shameful considering the loss of life.

[yellowbird135]

yellowbird135, is this ok?

Absolutely....I read and try to learn from it....and in general, I appreciate your views.....for your professional knowledge, and also for entertainment value....

[Thomas coupling]

Silsoe and yellowbird, to be pedantic, however - in reality the RAD ALT is a history gauge. It canot tell you what is coming, it is telling you what height the land was that just passed underneath its beam. Rely totally on rad alt and you will be behind the eight ball for sure.

EOL @ night - pot luck.........Strathclyde et al.

[SilsoeSid]

Quite right TC, and to be even more pedanticer, couldn't we say that everything we see is historic

I think you'd agree though that it would be better to have a slightly historic indication of the surface that we have just flown over, calculated and indicated for us by the rad alt, than having to remember the topography and every contour line of that area; and then have to work out an historic elevation of that surface based on the QNH, that may have changed up or down while on the task ... at the same time handling a double engine failure ... at night

[[email protected]]

You might find that the rad alt produces a cone rather than a line-beam and the T/R processes the returns to an average result.

Flaring the aircraft would give the result a slight bias as to what was ahead of you rather than what you had just passed over.

[tecpilot]

Just as reminder, EC135 pilots are teached in the actual SIMs to do a night auto according to the indication of the radalt. And the RFM tells the altitude to flare. As any pilot should know, baralt can't used on autos because of the long indication lag despite a non useful pressure setting.

[yellowbird135]

AR at night:

Once in the flare the Rad Alt indication is no longer top of my priority list....I mean I now spend most of my time outside to get my visual references right (hopefully). Rad Alt audio still helpfull though.... Maybe had time in the descent to set the decision bug to 50' or something like that as an additional clue....

[SilsoeSid]

Too true yb135, once in the flare the rad alt has already done it's job; on the way down she's working as a good, quick, easy to see reference to when you're approaching that c100ft.