Blip,
Interesting subject, worth a response.
Yes this is a topic that is rather neglected by both pilots and the Authorities who design instrument approaches.
Yes to the former but not to the latter. Instrument approach design is based on transition from an unacceptable visibility to a position where a specified minimum visibility should allow you to safely land the aeroplane. It is a
descent plan. The international standards only consider all engine operations (AEO) in normal configurations because there are far too many variables to consider for OEI or other abnormal operations. It is not neglect, it is a choice between delivering a result or nothing.
Here in Australia the regulations state:
"In the event that a missed approach is initiated prior to arriving at the MAPT (Missed Approach Point), pilots must fly the aircraft to the MAPT and then follow the missed approach procedure."
They mention nothing about initiating a missed approach beyond the MAPT and below the Approach Minima. It seems you are left to your own devices.
The design criteria are that you go around before or at the MAPT unless you can safely land. The designs are 3D designs that require a starting position (lat/long/alt) and MApp gradient to be of any use. How many possibilities would you consider for other options while trying to provide a useful minima?
Any time you have to do something outside the design criteria, you are left to your own devices because you are the person who knows the likely circumstances, possible failures, performance consequences, personal capabilities, etc.
There are plenty of reasons why you might need to initiate a missed approach beyond the MAPT.
1) Subsequently lo(o)sing the required visibility.
2) Excessive crosswind/ downwind.
3) Windshear
4) Runway occupied by:
a) departing aircraft taking too long to initiate take-off roll.
b) previous arriving aircraft taking too long to vacate runway.
c) runway incursion by taxiing aircraft.
And there is absolutely no reason why an engine failure could not occur at that time. Sudden application of go-around thrust, bird ingestation. etc.
Yes, all that is true. It also should form the basis of your plan for safe flight. In many ways, the instrument approach design is now irrelevant, since you are flying outside the design parameters. You now have to get the aeroplane back to the MAPT if you wish to use the information that the MApp procedure provides. So now you have to have a
climb plan to get there. That involves totally different obstacle considerations and protected airspace options that are totally unrelated to the approach design.
Along the lines of what Winston said, just imagine the scenario when you are taking-off from the same runway. If your company has published a special procedure to follow in the event of an engnie failure during the take-off, follow that procedure.
NO, NO, NO - unless you can position the aeroplane within the confines of the take-off splay some 2 km away (for CAO 20.7.1B within 76.2m or 90m either side of centreline at the end of the TODA) given crosswind, yaw, control issues etc then the special departure procedure (SDP) is potentially very unsafe. You need to consider more broadly protected airspace that applies to where you are commencing your go-round.
Remember too that the clean-up/ acceleration altitude might be higher than normal.
That is certainly true, particularly as the SDP acceleration altitude is only valid if you are within the splay and not closer to the obstacles than for the take-off case. ICAO Instrument procedure design does not allow for level acceleration segments - another complication for OEI MApp planning!!
So, we have touched on two very separate issues. One is OEI MApp planning and the other is contingencies during descent below MDA/DA. They are both complex subjects with many variables.
and LOKE,
There is a suggestion of a higher minimum – but at times this can become very restrictive.
May I suggest you need to reconsider your attitude to the inconvenience of raising the minima to improve the safety of the MApp flight path - the professional decision is accept that there are times when the weather precludes you from going to certain places. Should you decide otherwise, then you become the person who may be required to defend your acceptance of the risk.
Stay Alive,