Precautionary Landing

[bill.lumbergh]

Been a long time since i've practiced one of these and can find NOTHING on the net regarding procedured. Can someone refresh my memory?

[bentleg]

The Information Manual for the Aircraft will have a section about this under Emergency Procedures.

Seriously sus out the place where you are going to land, including a low pass to check for obstacles etc, brief pax, PAN call perhaps, pre-landing checks, master switch off, ignition off, then land.

[wishiwasupthere]

70-75kts and 1/3 flap

1) Timing run at 500ft AGL, working out distance using the rough formula IAS divided by 2 multiplied by time in seconds which will provide rough length in metres. Also inspecting the undershoot / overshoot for the following leg.

2) Visual inspection at 200ft, and inspecting suitability for the following leg.

3) Final visual inspection at 50ft. Only needs to be flown if something on the strip warrants closer inspection.

I don't think that there is a standard procedure for a prec search so it will be interesting to hear how others do it.

[Jabawocky]

Simple, do it at 80 knots which is safe above stall and slow enough to look.

Time it....yes in seconds! and its 41.something M/sec..... or just say 40m/sec.

If you can not do that simple maths in your head find somewhere to crash! :eek:

[ReverseFlight]

My advice is to borrow a book or some notes and practice with a qualified instructor in a remoter location where you don't annoy the hell out of the locals.

The main point to bear in mind is a precautionary cruise which invariably involves a lower engine power and some flap so that (1) you fly slower (2) there's better forward and downward vis and (3) the stall speed is reduced.

[muffman]

Just to dwell unnecessarily on the issue of timing the field's length.....one way would be to always fly the timing leg at the same speed and work out beforehand how many seconds you require. The effect of wind could be allowed for by flying slightly faster into a headwind or slower with a tailwind (or just adjusting the time using common sense.)

The correct formula is 1/2 ground speed x time (in sec)

If you're interested, the way the simple formula is derived shows how accurate it is:

If your GS is say 80kts, that's 80nm per hour. To time a field and get its length in metres we need to first convert 80kts into metres per second.

So 1nm = 1852m and 1hr = 3600 seconds. So 1nm/hour = 1852m/3600sec

1852/3600 is pretty close to half.... It's 0.514 in fact.

So to convert your speed from knots to metres per second, just halve it and you'll be within about 2.8% of the correct answer.

In the 80kt example, if you timed a 14 second field, the correct distance would be 576m. Using the rule of thumb, you get 560m. 2/5 of bugger all difference. :ok:

(Also useful to know if you ever fly in china, where things like wind are expressed as m/sec.)

[A37575]

The main point to bear in mind is a precautionary cruise which invariably involves a lower engine power and some flap so that (1) you fly slower (2) there's better forward and downward vis and (3) the stall speed is reduced.


In a single engine light training aircraft of the Cessna/Warrior?Jabiru class, the stall speed is so low that you do not need to select any flap and in any case lowering flap does not necessarily allow a better forward view. With a high wing type you have a good view at all times. The lowering of partial flap was aimed at high performance singles such as the Mustang, Wirraway and other relatively high wing load types with poor view over the nose and where the nose attitude was slightly lower with flap down.

Much of what is published in current flying training books on such things as a precautionary landing, were based upon early wartime types where lack of navaids and presence of poor visibility in UK plus less reliable engines made navigation more demanding. Keep in mind most of the current flying training techniques were developed pre-war and published in Royal Air Force manuals which in turn were used by the RAAF post war. As the majority of instructors in the aero clubs were former Air Force pilots and some became DCA Examiners of Airmen it was their job to write flying instructor training manuals. From these came commercially available flying school manuals.

The chances of having to conduct a true precautionary search for suitable field and then having to make a true short field landing, are remote. Especially with cheap GPS units commercially available.

True short field approaches and landings flown on the point of stall are a military technique (like landing on an aircraft carrier) and not applicable to present day light singles who already have a certified over the fence speed published in their POH. That published speed has safety factors applied but there was no safety buffer on true short field landings flown barely above the stall and almost literally "hanging on the prop"

You can be sure the lawyers would nail - you as would CASA - if you were caught flying on the point of stall on final approach instead of the POH published minimum approach speed.

[RadioSaigon]

...master switch off, ignition off, then land.

Why would you turn a safe comfortably controllable precautionary landing into a FLWOP???

IMO that's making it all much harder than needs be. Sorry bentleg, I disagree. That's the sort of advice that leads to bent metal and injuries.

[The Green Goblin]

Quote:
Originally Posted by bentleg
...master switch off, ignition off, then land.
Why would you turn a safe comfortably controllable precautionary landing into a FLWOP???

IMO that's making it all much harder than needs be. Sorry bentleg, I disagree. That's the sort of advice that leads to bent metal and injuries.

I was going to pick that up too!

Perhaps he had to many glasses of red and was getting confused with a forced landing!

[bentleg]

Perhaps he had to many glasses of red and was getting confused with a forced landing!


Yep, I was talking about a forced landing with power, not what was asked.

[vee1-rotate]

Yep, I was talking about a forced landing with power, not what was asked.

umm....huh?? Still havent sobered up, or...?

[The Green Goblin]

Perhaps he had to many glasses of red and was getting confused with a forced landing!
Yep, I was talking about a forced landing with power, not what was asked.

You're going to have a bentleg after the boss kicks the **** out of your behind after conducting such an interesting procedure :}

Know wonder CASA are now conducting initial issue of grade 3 instructor ratings if this type of rubbish is being taught :eek:

Remember after vacating the said aircraft if damaged the MMFM drills or in laymans terms Mags - on, Master - On, Fuel - On, Match - Lit :)

[RadioSaigon]

...was talking about a forced landing with power...

really... :ugh:

Review your posts, and the replies

[bentleg]

Originally Posted by bentleg
...was talking about a forced landing with power...
really... :ugh:

Review your posts, and the replies

In view of the Sh*t being thrown, perhaps someone might care to explain why Cessna recommend the following for a forced landing with power -

http://i87.photobucket.com/albums/k129/bentleg/172R.jpg

[Pilotette]

Bentleg, in your initial post you say to switch the ignition off then land, however the Cessna manual page you posted to back up your argument says to touch down and then switch the igintion off..I think this is what people are getting at...no point switching the ignition off before landing! :ok:

[AussieNick]

if practicle do your 200ft pass offset to the right of the strip, that way you can get a better look at the conditions, just remember not to get too focussed as many a pilot have plowed in when doing a prec search cause they got fixated on what was outside and not flying the aircraft

[b_sta]

Bentleg, in your initial post you say to switch the ignition off then land, however the Cessna manual page you posted to back up your argument says to touch down and then switch the igintion off..I think this is what people are getting at...no point switching the ignition off before landing!

Unless you really want to make it a forced landing rather than a prec landing of course :}

[RadioSaigon]

:ugh:...<sigh>

[overhere]

Bill - practise this with a flight instructor at your next AFR - I've seen people (and relatively experienced PPL'ers) come unstuck doing these - fairly low level flying, at lower then normal speeds, flaps set & more impact of wind is not what a lot of people are comfortable with. If you have a massive desire to do this yourself as someone suggested go find a strip someone that has flat terrain all around and no high trees - especially around the base/final legs.

In 10+ years of instructing & charter I only ever did one of these for real and it was to inspect a grass strip after a fair bit of rain - I was taking a twin in with lowish props & didn't want to bend anything - as others have said it's fairly rare to do one for real. The benefit is at least you'll get some flying in the bad weather configuration of your aircraft.

[RadioSaigon]

Actually, on closer inspection of the Cessna checklist published above, I do have a couple of issues with the advice offered there...

It's a precautionary landing of a perfectly serviceable aircraft in a place other than your intended destination. That Cessna checklist is bloody near well on the way to creating an emergency situation out of what should be a relatively low-stress out-landing... avionics off, electricals off... what happens to the bloke reading that under a little more stress than usual that then goes and flicks the ALT/BAT masters off too, thinking that's what the checklist said to do -in the process robbing himself of lights, radios, flaps etc.??? Not overly helpful. (yes I do know it mentions the Master later after flap-extension, but...)

Then immediately after touchdown the checklist wants 1st the Ignition selected to OFF and then the mixture to idle-cutoff! That more than a bit arse-backward (hot engine, fuel in the induction) to my way of thinking -not to mention unnecessary at that point. Better yet, the master will still be on so you can get the flaps up and the aircraft weight on the mains, the pilot will then concentrate on controlling the aircraft landing roll, then perhaps later in the landing roll (when everything is well under control) mixture to idle-cutoff and switches off -if necessary.

Don't reckon there was necessarily a helluva lot of thought put into that particular checklist -heaven forbid anyone take it as absolute gospel and act on it in the event of a live precautionary. Hands everywhere like that means concentration ain't where it outta be. Lots of potential there I reckon.

[Lodown]

Like someone mentioned earlier, precautionary landings have a history dating back to ancient aviation times with partial radio coverage, poor weather forecasts and party line phone communications. The Cessna checklist posted by Bentleg is preparation for a crash. Once safely down and stopped, turn everything back on and clean up.
I've had to do many strip inspections using similar techniques. Checking for water puddles, mudholes, fences, anthills, stumps, saplings, ditches, old ploughs, dead cattle in the grass, irrigation pipes, unused fenceposts and other obstructions on a patch of dirt that the squatter swore was used by large twins. (After landing you find out that the squatter was referring to the one Army Caribou that landed in the same paddock 45 years ago and was never seen or heard from again.)
Several things that I try and remember are:
1. Look out for power lines in your flight path before concentrating on the landing area.
2. Obstacles in long grass will be easy to see from overhead, but won't be seen on approach or landing.
3. Fences and loose fencing wire offcuts are hard to see.
4. Single line telephone wires on old, short wooden poles are very hard to see until you land under them.
5. Your eyes will be looking down. Be careful when you turn at the end of the run. Be aware of wind and drift, particularly if turning with the wind and still concentrating on the end of the landing area.
6. Small anthills in long grass can be a big hazard. They can't be seen until you're on the ground and still doing 40kts.

[Joker 10]

Lodown, Good post, we all should remember why we might need a precautionery, too ofter it is just taught by rote out of a syllabus and the reason for it is never understood.

Most GR 3 have never actually done an operational precautionery

[riseagainst]

Yea some good tips,when i was training i used to also turn the di to a cardinal heading over the field for reference.

[RadioSaigon]

The Cessna checklist posted ... is preparation for a crash

Precisely. Put yourself in that mind-set, guess what'll happen? That's the problem I have with the checklist.

Like you, I have had to do many low-level inspections of impromptu landing sites, including beaches, paddocks, "strips", lakes, rivers, harbours, bays, ocean waterways and other less formal areas. The advice you offer is excellent. To my way of thinking a precautionary landing is conducted well before it becomes a "do it now or crash very soon" scenario, which implies that the pilot will have time and opportunity to find and properly assess a precautionary landing site, which of itself should (read: must) preclude the necessity of conducting a pre-landing checklist that is "preparation for a crash".

As others have intimated, this is an airborne exercise taught by rote, in slavish adherence to a checklist 1st published 40-60 years ago which was probably quite appropriate to conditions then -not necessarily now. Just no one has bothered to actually evaluate the checklist and update it to reflect more relevant conditions or scenarios. Of far more importance IMO would be teaching pilot candidates to properly recognise when and where the conditions and need for a precautionary landing may soon exist and then to act appropriately in those conditions.

[Kickatinalong]

Bill check your PM's
Kickatinalong:ok::ok::ok: