Discuss the problems and solutions to all of the situations that Pilot X finds himself in.
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By G-BLEW
#932750
Winter Blues

Pilot X obtains his IMC Rating to make good use of his new share in a Rockwell Commander. His first solo flight follows weeks of bitterly cold winter weather… By Richard Boswell

Overnight the temperature rose by six degrees. The ice started to clear as quickly as it had formed and it appeared that the entire country breathed a collective sigh of relief. The temperature was now +3°C, still technically cold for this time of year but significantly warmer than the last three weeks. And with a south-westerly wind, rather than the biting northerly that had become the norm, the temperature increase felt dramatically more than the six degrees.

X was itching to go flying. His last flight had been almost a month ago and that flight had been the successful conclusion of his IMC rating. This was something he had been meaning to undertake for many years, although there was always something else that seemed more important. However, the rating became a priority three months ago when he acquired a quarter-share in a Rockwell Commander 112 TC. This aeroplane was a big step up in performance, both in terms of airframe and avionics; this aircraft was fully airways-equipped. During the checkout, X quickly realised that in order to get the maximum from this aircraft he needed to upgrade his skills and his licence. He bit the bullet, enrolled on the IMC course and found time at weekends to actually complete it.

The day of his final test had been cold, clear and crisp – a classic winter’s day with not a breath of wind. It turned out to be the perfect day for flying on instruments, with the cold air remaining smooth through the flight and no drift at all. That evening, X had gone to the pub to celebrate – and that same night the temperature dropped below freezing, staying there for the next three weeks with snow and ice increasingly hindering everyday life. For most of this time his base airfield had been closed simply because they didn’t have the resources available to keep the runway and taxiways clear. Now the big thaw was almost complete and X was determined to go flying.
The route was simple and one he had done many times before – a fifty-minute hop to a small, tarmac airfield out to the west that had a decent restaurant. Recently, the field had been equipped with an ILS, which, with his new aircraft and skill set, gave X an added degree of comfort.

The weather seemed OK for the trip; the westerly wind had brought in a layer of stratus at 1,500ft but with the highest ground en route being just under a 1,000ft this shouldn’t be too much of a problem. The visibility was 5km at both departure and arrival airfield. Not perfect, but legal... and X had the comfort of his new rating which gave him a confidence he had not experienced before.

Missed approach

Ten minutes into the flight, X found himself having to make a decision. As he flew to the west, the cloudbase had slowly lowered from 1,500ft to 1,200ft, with his destination airfield reporting a base of 1,000ft above aerodrome elevation. However, he had the minor problem of the high ground located between his present position and destination. He engaged the autopilot and considered his options.
He could push on below cloud, but obviously this would put him close to the top of the high ground. He could turn around and go home; there was no pressure on completing the trip other than the pure joy of flying. Finally, he had the option of climbing and going over the top. The cloud tops had last been reported as 2,500ft, so the cloud layer should be relatively thin. The option of turning around was probably the safest, but there was no reason not to climb, apart from a slight apprehension of taking the aircraft deliberately into IMC without an instructor sitting next to him. He requested a climb to 5,000ft and, once granted, he disengaged the autopilot, focused on the instruments, opened the throttle and started the climb.

At first, his nerves made X a little unsteady. However, he forced himself to concentrate on the AI and keep his scan going. At 2,400ft he burst out of the cloud into blue sky. He continued the climb up to 5,000ft and re-engaged the autopilot. He checked the Ts & Ps were normal, but with an air temperature of -10°C he needed to the turn the heater up a little and direct the air down to warm his freezing feet.
Thirty minutes later, with ten miles to go and clear of the high ground, he requested a descent and vectoring for an ILS approach. He was cleared to 2,000ft and with his approach checks complete and ILS frequency correctly selected and identified, he closed the throttle and started the descent. At 2,500ft he entered cloud and checked the temperature again, which was just above freezing meaning a chance of engine icing. Still, the airframe should remain clear. He levelled at 2,000ft as instructed and concentrated on the dials again. He stayed firmly fixed on the instruments as he was vectored onto the ILS. When safely established on the localiser, he descended with the glide path and double-checked that he had the QFE selected. At 1,200ft he glanced up to see the runway; nothing yet, so back on the instruments. Another quick peek up at 1,000ft and then again at 800ft, but still nothing seen. He confirmed the cloudbase with the Tower – they confirmed it remained at 1,000ft. X was perplexed. He had imposed a minimum DH on himself of 500ft, just had his instructor had advised, but this first solo approach wasn’t meant to be down to his limits.

At 500ft he looked up again. Could he see something ahead? He wasn’t sure and descended another 50ft… 450ft became 400ft before the penny dropped. He applied full power and instigated the go-around on instruments just he had been instructed. Once safely climbing away, he selected the heater to demist.

1 Why couldn’t X see the airfield even though he was in VMC?
2 What golden rule did X break?
3 What other airframe systems are prone to this kind of icing?
By Tony Hirst
#933195
He couldn't see the airfield because the aircraft and screen were covered in a layer of Hoar frost due to descending his cold soaked aircraft from altitude into the stratus. However, the text describes lowering stratus which sounds like an approaching warm front and the risk of freezing rain.

I suppose there is a risk that the Hoar frost could affect the static ports ( as could freezing rain) as they are generally not heated.

To be honest I am not sure what golden rule he broke. Is descending below a self imposed minima or below the recommended minima for an IMC rating a golden rule? Also, No mention of an alternate or how he intended to descend below the 1500' cloudbase with descending below MSA should he have to divert or return.

Regardless, it doesn't read as if X had sufficiently comprehended the risk he was undertaking due to his experience applying the rating, time out of an aircraft that was a step up for him and the condtions.
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By Keef
#933275
+3°C on the ground implies it's going to be freezing not far above 1000 feet.
Did he consult the met reports to see where the freezing level is? Or what the temperatures are at various altitudes?

I have a personal rule that I don't enter IMC if it's below freezing, unless I know the layer is thin and I can get through it quickly. The Arrow has no FIKI capability, and I'm not brave. If I see embedded CBs in the forecast, that's enough to keep me on the ground.

Pilot X couldn't see the ground when he popped below cloud because of the frost (aka rime ice) on his screen.
Golden rule broken? Several - first, don't enter IMC if it's below freezing.
If you have no option, always turn on everything you've got to minimise icing problems, even if it is only screen demist and pitot heater.

Other systems prone to this kind of icing? The wings, the elevator...

It's not as drastic as clear ice, which can build up alarmingly quickly, but it does spoil the handling characteristics of the aircraft, and it makes it hard to see out.
By johnm
#933394
1 Why couldn’t X see the airfield even though he was in VMC?

Probably because the widscreen had iced upand it can be very hard to distinguish between cloud and iced up screen.

2 What golden rule did X break?

He descended below minima and did an instrument approach on the dreaded QFE, QNH, laddie QNH

3 What other airframe systems are prone to this kind of icing?

Static port ,air intake, carburettor, how long a list would you like?
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By Gertie
#935888
As a new IMCR holder who goes looking for clouds to fly in I know what I would have done different.

(1) With 3 degrees on the ground I would not have gone looking for cloud - VMC only.

(2) Having decided on my DA and written it on the approach plate I would not have descended below it.
By SteveKR
#935947
Seems like the questions have largely been aswered, but....

- The legal minimum DA for an IMCR pilot is 200ft above the full IR DA and never less than 500ft aal regardless of the actual system DA, so he broke that rule.
- We were not told either what the actual DA is. It may well have been less than the 500ft he was allowed, but did he actually know this? Was he carry the plates?
- Cloud in icing conditions? Not for me.

Personally as a low hours IMCR, I wouldn't enter IMC unplanned unless I had to. Workload is high enough without having to calculate minimums and brief for the approach without a bit of prior preparation. A month after last flying I would also not consider myself current to fly down to minimums.

Also cloud base is lowering towards the west, 5km vis (so high humidity), and humid air coming from the west where he's going. With 40 minutes still to go I'd be thinking that there has to be a fair chance cloud base is going to continue to get lower, possibly to the point where he couldn't get into his destination airfield and maybe even his home base if he's flying around long enough. Guess it depends on the forecasts and how accurate they've been so far, but on the face of it, he was not expecting the weather as it actually turned out. Why push on if you don't have to?
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By Keef
#936416
SteveKR wrote: - The legal minimum DA for an IMCR pilot is 200ft above the full IR DA and never less than 500ft aal regardless of the actual system DA, so he broke that rule.


Actually, it isn't. That's a recommendation, not a legal minimum.
By Splendid Cruiser
#936766
Specifically:

AIS AD 1-1-8

3.3.2.1 Pilots with a valid Instrument Meteorological Conditions (IMC) Rating are recommended to add 200 ft to the minimum applicable
DH/MDH, but with absolute minima of 500 ft for a precision approach and 600 ft for a non-precision approach. The UK IMC Rating may
not be valid outside UK territorial airspace, therefore IMC Rated pilots should check the validity of their rating for the State in which they
intend to fly. If the rating is not valid pilots must comply with the basic licence privileges, subject to the regulations of that State
By Splendid Cruiser
#937865
Actually, this reminds me of a previous discussion. The wording suggests that the 200' addition is recommended, but that the 500'/600' absolute minimum is mandatory.

However, I received this reply from the CAA on the subject a few years ago stating it is all recommended:
RE: IMC DESCENT MINIMA ENQUIRY.

Thank you for your enquiry concerning IMC Descent Minima. I apologise for
the delay in response.

In AIP AD Section 1.1.2 Para 3.2.2.1 pilots with a valid Instrument
Meteorological Conditions (IMC) Rating are recommended to add 200ft to the
minimum applicable DH/MDH, but with absolute minima of 500ft for a precision
approach and 600ft for a non-precision approach.

This can only be a recommendation as it is not included in the Air
Navigation Order 2005 or other form of regulation.

This recommendation is derived from Schedule 8 Part B(1)(2)(b) of the order
which provides that the holder of an IMC rating may not take off or land
when the flight visibility below cloud is less than 1,800 metres. On a
standard 3 degree approach, an aircraft breaking cloud at 500' or 600' will
typically require at least 1,800m visibility in order to achieve sufficient
visual reference for a safe landing. Legally there is no impediment to the
holder of an IMC rating descending to a lower specified decision height on
an approach if the flight visibility exceeds 1,800m, but whether this is
wise or not is an entirely different matter.

The CAA has no plans to amend the ANO so as to mandate this recommendation.
Of course, if we consider that there is a need to do so we will revisit the
position.

Yours sincerely
Personnel Licensing Department
United Kingdom Civil Aviation Authority
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By KNT754G
#938649
Accepting that the IMCr additions to minima are recommended (I have flown to IR descent minima several times on my IMCr) I find it strange that the PLD man says
This can only be a recommendation as it is not included in the Air
Navigation Order 2005 or other form of regulation.


The AIP is a Statutory Instrument and hence a legislative document, otherwise the "Approach Ban" would be unenforceable.

AIP AD1.1 paragraph 8 refes (the URL is way too long)
By Splendid Cruiser
#938945
The AIP is a Statutory Instrument and hence a legislative document, otherwise the "Approach Ban" would be unenforceable.

I don't believe the AIP is as such. The AIP references legislation to form the requirements. As per your example. The ANO does indeed describe the approach ban making it enforceable thus:
An aircraft to which article 38 applies, when making a descent to an aerodrome, shall
not descend from a height of 1000 feet or more above the aerodrome to a height less
than 1000 feet above the aerodrome if the relevant runway visual range at the
aerodrome is at the time less than the specified minimum for landing.
By profchrisreed
#939585
Definitely not a statutory instrument, but merely (as it says) an Information Publication.

Were there any conflict between the AIP and the ANO or other legislation, the version to comply with is that in the legislation not the AIP.
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By KNT754G
#940535
An aircraft to which article 38 applies, when making a descent to an aerodrome, shall
not descend from a height of 1000 feet or more above the aerodrome to a height less
than 1000 feet above the aerodrome if the relevant runway visual range at the
aerodrome is at the time less than the specified minimum for landing.


Actually a trifle more complicated than that.

AIP 1.1-16 states (currently ) that
8.1 The requirements for the commencement and continuation of an approach are defined in Articles 47, 48 and 49 of the Air Navigation Order 2005.


Unfortunately the ANO is currently at ANO 2010 and Articles 47, 48 and 49 have no relevance to the Approach Ban.

ANO2010 Articles 107, 108, 109 apply, and 107 references Article 83 (not 38) for UK registered Public Transport aircraft.

The rest of it (non ukl and non PT) are explicit in 108, 109.

It does, however, highlight the fact that when rewriting the AIP CAA did not conduct an adequate Impact Analysis on what other documentation would be affected :D