Other aviation hazards

[Discorde]

In recent incidents in aerial public transport ops (including the JAL landing collision and B737 door blowout) some commentators have noted that regulatory authorities are slow to respond unless large loss of life is involved. Here are some other current aviation hazards that (thus far) have not caused severe accidents but have the potential to do so:

Low and variable transition altitudes in non-US states. Mis-set altimeters can lead to level busts or terrain warnings. In the UK the CAA issue notams about altimeter settings whenever a low pressure weather system occurs. A world-wide TA of (say) 20,000 ft (or 6000m in metric areas) would allow altimeter resetting during climb and descent to be done during low workload flight phases.

Currently rapid depressurisation checklists mandate immediate initiation of descent without regard to ATC requirements. These checklists originated many years ago when high altitude air traffic density was much lower. An airliner plummeting through busy airspace these days might trigger multiple conflicting nearby TCAS RAs or, in the worst case scenario, collide with traffic below. The mantra 'aviate, navigate, communicate' is clearly not relevant in this situation.

Climate change is generating stronger surface winds which in turn will increase the incidence of landings with severe crosswinds. YouTube videos seem to suggest that landing with crab is now acceptable, but a mishandled landing might lead to gear collapse or airframe/engine ground strikes. Perhaps crosswind landing technique should be debated and standard procedures established, perhaps specific for different aircraft types.

Overhead luggage compartments in airliner cabins should be locked for take-off and landing to prevent delays to evacuations.

[Jwscud]

My personal biggest concern is incorrect data entry/incorrect intersection departures leading to crews trying to get airborne with insufficient flap/thrust. There have been a few incidents already where only the grace of god has prevented a hull loss.

[Consol]

12 pages of NOTAMs per airport?

[Easy Street]

Currently rapid depressurisation checklists mandate immediate initiation of descent without regard to ATC requirements. These checklists originated many years ago when high altitude air traffic density was much lower. An airliner plummeting through busy airspace these days might trigger multiple conflicting nearby TCAS RAs or, in the worst case scenario, collide with traffic below. The mantra 'aviate, navigate, communicate' is clearly not relevant in this situation.

Are you proposing here that aircraft should remain at their cleared level while depressurised and communicate with ATC before initiating emergency descent, working from the idea that emergency oxygen will supposedly last 15 minutes or so? If so, have you considered that time of useful consciousness is measured in single-digit seconds at modern airliner cruise altitudes? It is doubtful IMHO that all passengers and cabin crew would succeed in donning masks, much less be able to report 100% success to the flight deck in any kind of meaningful timeframe, so the only course open to pilots wishing to maximise the chances of survival of anyone who's failed to don a mask is to descend immediately upon depressurisation. A depressurised cockpit is not a place for complex thinking, cross-monitoring, assessing the state of the cabin, or negotiating a descent clearance with ATC - all communication is difficult under emergency oxygen, and anyone who has undergone decompression training can attest to the shock inducing effect of sudden cold and hyperventilation, which is likely to persist until some time after emergency oxygen is established. What's needed in this situation is a simple, mechanical drill which addresses the immediate and otherwise-inescapable threat to life presented by high cabin altitude. By comparison, midair collision is only a possibility, and one which other parties (not suffering the immediate and certain threat of decompression) can do their part to avert with full mental capacity in relative warmth and comfort. The existence of TCAS surely makes this a much safer procedure than it was many years ago. Triggering multiple RAs should be the least of anyone's concerns in this situation because TCAS is very good at changing its instructions as required to deal with the highest threat, whether that is the descending emergency aircraft or another aircraft making an RA against it.

I will accept that the accuracy of GNSS navigation increases the risk posed to emergency descent scenarios by aircraft being precisely on published tracks, rather than scattered either side of them as in days gone by, but TCAS more than compensates for that IMHO. The best way to reduce that risk is to reduce the use of published tracks, and indeed we are seeing growth of free route airspace in the upper air.

Late edit: I should also have mentioned decompression sickness, for which there is no defence other than immediate descent if severe injury, disability or potential death is to be averted. Think of its effect on the body as similar to the effect of opening the cap on a bottle of carbonated drink... except those bubbles are potentially fatal, so you don't spend time planning how best to screw the cap back on, you get the hell on with it. There's no hope of finding a hyperbaric facility capable of treating hundreds of pax simultaneously....

[Waghi Warrior]

My immediate action after doing the decompression drill would be to get off the airway (turn left or right 90 degrees initially) during the initial descent, in order to avoid other traffic on the airway.

[blue up]

My immediate action after doing the decompression drill would be to get off the airway (turn left or right 90 degrees initially) during the initial descent, in order to avoid other traffic on the airway.

In the UK you DONT do this due to the density of Airways. Stay on track so ATC can move people away from YOU.

[ETOPS]

suggest that landing with crab is now acceptable


Ex 737-400 and 747-400 pilot here. Wings level at touchdown or pod strike! Training all focussed avoiding wing down even to the extent of having the cockpit close to the upwind edge of the runway with max crosswind in the ‘47…

[Discorde]

Are you proposing here that aircraft should remain at their cleared level while depressurised and communicate with ATC before initiating emergency descent, working from the idea that emergency oxygen will supposedly last 15 minutes or so? If so, have you considered that time of useful consciousness is measured in single-digit seconds at modern airliner cruise altitudes? It is doubtful IMHO that all passengers and cabin crew would succeed in donning masks, much less be able to report 100% success to the flight deck in any kind of meaningful timeframe, so the only course open to pilots wishing to maximise the chances of survival of anyone who's failed to don a mask is to descend immediately upon depressurisation. A depressurised cockpit is not a place for complex thinking, cross-monitoring, assessing the state of the cabin, or negotiating a descent clearance with ATC - all communication is difficult under emergency oxygen, and anyone who has undergone decompression training can attest to the shock inducing effect of sudden cold and hyperventilation, which is likely to persist until some time after emergency oxygen is established. What's needed in this situation is a simple, mechanical drill which addresses the immediate and otherwise-inescapable threat to life presented by high cabin altitude. By comparison, midair collision is only a possibility, and one which other parties (not suffering the immediate and certain threat of decompression) can do their part to avert with full mental capacity in relative warmth and comfort. The existence of TCAS surely makes this a much safer procedure than it was many years ago. Triggering multiple RAs should be the least of anyone's concerns in this situation because TCAS is very good at changing its instructions as required to deal with the highest threat, whether that is the descending emergency aircraft or another aircraft making an RA against it.

The hypoxia and other distressing effects you describe would clearly be less injurious to the overall physical wellbeing of passengers and crew than mid-air collision.

Perhaps positive pressure oxygen systems for passengers and cabin crew would help to mitigate hypoxia effects while the flight deck crew attempt to negotiate an emergency descent clearance with ATC.

Hopefully this headline will never appear in our newspapers:
.COLLISION AIRLINER DESCENDED WITHOUT PERMISSION AFTER CABIN AIR PRESSURE FAILURE

[Easy Street]

The hypoxia and other distressing effects you describe would clearly be less injurious to the overall physical wellbeing of passengers and crew than mid-air collision.

Perhaps positive pressure oxygen systems for passengers and cabin crew would help to mitigate hypoxia effects while the flight deck crew attempt to negotiate an emergency descent clearance with ATC.

Hopefully this headline will never appear in our newspapers:
.COLLISION AIRLINER DESCENDED WITHOUT PERMISSION AFTER CABIN AIR PRESSURE FAILURE

How about "TEN DEAD, SCORES BRAIN DAMAGED AND DISABLED AFTER PILOTS FAIL TO GAIN PERMISSION FOR DESCENT AFTER CABIN AIR PRESSURE FAILURE"? That would not be great either. We treat certainties ahead of contingencies. As to positive pressure breathing systems: setting aside cost and complexity for an unrealistic moment, think about the amount of training required to use those effectively and tell me that they're a realistic option for pax, including infants, those afraid of flying, and those who enjoy an alcoholic beverage or two during their journey. And they do precisely nothing to protect against decompression sickness or mitigate the effects of barotrauma. Having undergone decompression training on multiple occasions I must vigorously disagree with you.

[Fargo Boyle]

From an ex- ATCO... Emergency squawk will get ATC's instant attention, and not just the unit you're talking to. (or not, if you're sorting out the aeroplane.) If they see you start a descent they'll clear traffic below out of the way - if you have time to get a Mayday out then great, but I can't believe you would expect a crew to sit there drumming their fingers waiting to call ATC while someone else is transmitting...

[meleagertoo]

I'd suggest that a prime hazard is the sort of gash N American RT demonstrated by the Alaskan pilot during this event. Sloppy, indistinct, non-standard and non-specific rambling instead of a Professinal MAYDAY call - a word they never uttered.
Leave alone asking - yes! asking! for descent in a rapid depressurisation whilst evidently not wearing an oxygen mask - completely contrary to the memory drill...

[Lookleft]

Nothing to do with being American. I know of an incident in Australia where the crew didn't declare a Mayday with a depressurization. Part of the issue is the dominance of media in its various forms and it's focus on sensationalism. There has been plenty of that lately. IMHO crews from around the world don't want to draw attention to their situation even if it is depress. Don't forget the crew in the 737 weren't faced with the scenario that endless sim sessions train for and that is the failure at FL370. I would imagine that this crew were dealing with a fair amount of startle factor trying to understand why they were depressurizing climbing through 16000'. Which crew anywhere in the world would anticipate a part of the airframe detaching on a brand new aircraft?

[fdr]

Ex 737-400 and 747-400 pilot here. Wings level at touchdown or pod strike! Training all focussed avoiding wing down even to the extent of having the cockpit close to the upwind edge of the runway with max crosswind in the ‘47…

The offset works well on the B747/744, B757, B767, it doesn't behave quite so on the B777. If the drift is eased off by rudder with an offset on the B777, the aircraft ends up offset from the CL. It is one of two weirdnesses of the 777. The other one being that most aircraft will swing towards the wind direction on a takeoff, the B777 doesn't that initially, it actually has an out of wind tendency, that occurs until passing about 80-90 kts. These were so striking I went through the QAR data of aircraft to verify the perceived response.

[Big Pistons Forever]

12 pages of NOTAMs per airport?

//\\ What he said !

[Discorde]

From 'How To Do Well In The Sim':

https://cimg4.ibsrv.net/gimg/pprune.org-vbulletin/697x733/rapid_depress_18ce68994f1b472cc6f1c581e212b8dc4b80b592.jpg

This is a personal opinion - and probably a minority one, judging by other posters' comments. I never experienced a real rapid depress and therefore never felt the physical distresses described above.

[ATC Watcher]

Emergency descent ? Aviate first communicate next ..Do not ask permission , That what we are told to expect as en-route controllers. .Turing 15 Degrees off track is what is recommended in Oceanic airspace I believe ( it was in my days , correct me if I am wrong) but in dense Condimental airspace , makes no difference where you go laterally as there is likely going to be someone in your way , so squawking A7700 is the only sensible way to attract attention to the ATC sectors below you and like this everybody will try to keep others clear. Remember the R/T frequency you are in is possibly only a few thousand feet deep, In an emergency descent from say 38.000 ft to 10.000 above say Belgium you could cross no less that 6 different sectors , from 2 different ATC centers ..and possibly a TMA as well so the approach sector of an airport , and it could be a military one. , So "a mayday " will help only the first sector .
Squawking 7700 and just saying on the R/T : your calf sign + emergency descent to 10.000 ft is what I will do . In very busy airspace . or in shared CIV/MIL airspace , like China for instance,. switching to 121.5 is not a bad idea either as the military are likely to be tuned in and keep their aircraft out of the way.
. And to make things more complicated , as was said before, TCAS will not help much at these kind of rates of descent ..

[punkalouver]

The offset works well on the B747/744, B757, B767, it doesn't behave quite so on the B777. If the drift is eased off by rudder with an offset on the B777, the aircraft ends up offset from the CL. It is one of two weirdnesses of the 777. The other one being that most aircraft will swing towards the wind direction on a takeoff, the B777 doesn't that initially, it actually has an out of wind tendency, that occurs until passing about 80-90 kts. These were so striking I went through the QAR data of aircraft to verify the perceived response.


According to Boeing, the swinging toward the wind at lower speeds is called the Anti-Weathervaning effect and affects all Boeing twin jets. But I suspect that the bigger the engines, the more the effect as the crosswind acts on the nacelles(rotating the aircraft in one direction) versus the effect on the vertical tail(rotating the aircraft in the other direction).

[Chiefttp]

“Climate change is generating stronger surface winds which in turn will increase the incidence of landings with severe crosswinds. “

Really? Talk about drinking the Kool-Aid and blaming everything on a phenomenon that is in dispute.

[Chiefttp]

I'd suggest that a prime hazard is the sort of gash N American RT demonstrated by the Alaskan pilot during this event. Sloppy, indistinct, non-standard and non-specific rambling instead of a Professinal MAYDAY call - a word they never uttered.
Leave alone asking - yes! asking! for descent in a rapid depressurisation whilst evidently not wearing an oxygen mask - completely contrary to the memory drill...


The topic of “Mayday” vs “Emergency” comes up often on PPRune. I’ve been flying Jets since 1986 in the USAF and Commercially. All I can tell you is, in the U.S., we declare an “EMERGENCY” this phraseology has been hammered into US pilots since day one of PPL training. I would only say “MAYDAY” if I were flying outside of U.S. airspace, which I did regularly for 28 years. I’m not arguing with you as to which is correct, I agree there should be one standard phrase to convey a serious Emergency, and I understand everyone else uses the MAYDAY terminology except for the U.S. It’s just never been an emphasis item in any training program or directive. The use of “MAYDAY” was required by the USAF overseas, but never in U.S. Airspace. I don’t know why. Don’t get your “panties in a bunch” over the RT in this incident, believe me, when any pilot declares an “EMERGENCY” in the U.S. it will illicit the exact same response as declaring “MAYDAY”. Hopefully emphasis will be placed on ONE STANDARD Phrase in the future.

[Bleve]

YouTube videos seem to suggest that landing with crab is now acceptable ...

Videos and photos of landing aircraft with large crab angles are very misleading. A zoom lense will foreshorten dimensions in the fore/aft direction of the lense. The effect is to make any crab angle appear much larger than reality.

[Friendly Pelican]

In substantial oversimplification:

1. If requisite deviation without clearance is Engine-failure-related, maneouvre to an appropriate level +/- 500.
2. If similar deviation is Weather-related, manoeuvre to an appropriate level +/- 300.

I know the reasoning behind both - but wouldn't it be simpler if the procedure was origin-independent?

[Semreh]

... in dense Condimental airspace , makes no difference where you go laterally as there is likely going to be someone in your way...

So what you are saying is that when the airspace is peppered with aircraft, an aviator worth his salt will not change heading in an emergency descent, simply squawk on 7700 and R/T calf sign + emergency descent to 10.000 ft, and that cuts the mustard.

(Sorry, I have an unfortunate predilection for puns. Mods are free to delete this before I do. (Well, they can anyway, but I formally don't mind))

[punkalouver]

So what you are saying is that when the airspace is peppered with aircraft, an aviator worth his salt will not change heading in an emergency descent, simply squawk on 7700 and R/T calf sign + emergency descent to 10.000 ft, and that cuts the mustard.

(Sorry, I have an unfortunate predilection for puns. Mods are free to delete this before I do. (Well, they can anyway, but I formally don't mind))

Well, if the TCAS shows traffic left and right and none ahead, what would you do. How about aiming for areas clear of terrain and aircraft instead of blanket planning on one particular option which frequently does not make sense. On a major enroute airway in central Asia or over the ocean, likely a turn. Crowded European or North American skies might suggest a different plan.

[alf5071h]

The greater hazard is in the unforeseen, and how we react.
With uncertainty, we, humans remain a hazard to ourselves - how we manage surprise.

This has always been so, but arguably reducing in line with safety tends.
Conversely where most of the easier situational hazards have been identified, those which might be encountered are more likely to be unseen, or discounted with erroneous reasoning, and thus a surprise.
There is increasing need to be prepared to be surprised and consider how we might respond.

Safety discussions (as in posts above) often overlook the urgency in situations which has been considered previously, which is reflected in procedures:
If - Then - Act. There is no need to double think situations, particularly where thinking might be in short supply when surprised.

An emergency descent is based on physiological needs, not traffic density. Beware false reasoning.

[MarkerInbound]

The topic of “Mayday” vs “Emergency” comes up often on PPRune. I’ve been flying Jets since 1986 in the USAF and Commercially. All I can tell you is, in the U.S., we declare an “EMERGENCY” this phraseology has been hammered into US pilots since day one of PPL training.

The FAA AIM now says A pilot who encounters a distress or urgency condition can obtain assistance simply by contacting the air traffic facility or other agency in whose area of responsibility the aircraft is operating, stating the nature of the difficulty, pilot’s intentions and assistance desired. Distress and urgency communications procedures are prescribed by the International Civil Aviation Organization (ICAO), however, and have decided advantages over the informal procedure described above.
It goes on to discuss Mayday and Pan Pan so change is slowly coming but old habits are hard to break.

[74757677]

Bit like position and hold and line up and wait, behind. Never had a problem with the former tbh. It’s the States, do what you have to do. Respect to the Kennedy ground, tower and area controllers. (from a foreigner)

[Chiefttp]

74757677,
My Son flies 777’s internationally. He says that in the UK tower will request a crew to “Line up and wait behind the landing BA 747 for ex. Or he says they’ll even issue a clearance to “
line up and wait behind the second 737 landing”.
Is this true? It would seem to me that could be problematic if a crew gets the sequence wrong?

[jumpseater]

74757677,
My Son flies 777’s internationally. He says that in the UK tower will request a crew to “Line up and wait behind the landing BA 747 for ex. Or he says they’ll even issue a clearance to “
line up and wait behind the second 737 landing”.
Is this true? It would seem to me that could be problematic if a crew gets the sequence wrong?

No, not correct. A uk controller can only use a conditional clearance for the first aircraft on approach. If a clearance is given to line up after the second/third landing aircraft, that is incorrect and should be challenged.

The phraseology is
Atc
ABC123 Behind the landing X, line up and wait behind.
Response
A/c
Behind the landing X line up and wait behind.

Behind is emphasised twice, and the stop bar only deselected as the landing aircraft passes the holding point.

This can only be used in appropriate weather conditions, and when used with landing traffic for the first aircraft to land only.

[421dog]

In the US, any sort of “MayDay or Pan Pan” elicits the same response: “Understand you are declaring an emergency, what is the nature of your emergency and what are your intentions”. It is not a graded response, and will get you a great deal of attention in even the most densely occupied airspace. ATC will accommodate you quickly, get you what you need and get everybody out of your way (and you to a more discreet frequency and, if practical, location, with sufficient alacrity to keep the system functioning safely and efficiently.)
Aviate, Navigate and Communicate (in that order) are the expected procedures.

Been there, Done that, Got the T-shirt…

[Chiefttp]

Jumpseater,
Thank You for your response. My Son said the clearance he was given to by Stanstead Tower was line a up and wait after the second landing traffic. I’ll pass on to him that that clearance is not correct and not to accept it.

[ATC Watcher]

So what you are saying is that when the airspace is peppered with aircraft, an aviator worth his salt will not change heading in an emergency descent, simply squawk on 7700 and R/T calf sign + emergency descent to 10.000 ft, and that cuts the mustard.

(Sorry, I have an unfortunate predilection for puns. Mods are free to delete this before I do. (Well, they can anyway, but I formally don't mind))
I know you\re trying to score points but remember an emergency descent is an emergency., the goal you save your skin and that of the passengers behind you as soon as possible and there are no fixed rules that will guarantee a safe outcome. Years back I.ve been doing combined SIM sessions with one major European carrier to try to find solutions but there are none

The best we found is the 7700 squawk. and an initial call using your real call sign . What we found at the time is that in a real emergency , in stress pilots are often automatically reverting to the dummy call sign used in the SIM when practicing that emergency ..

[jumpseater]

Jumpseater,
Thank You for your response. My Son said the clearance he was given to by Stanstead Tower was line a up and wait after the second landing traffic. I’ll pass on to him that that clearance is not correct and not to accept it.

UK CAA Cap413, Chapter4 para 4.34 is the document to look at.
It is remotely possible that Stansted have a local procedure within their Mats Part2 that allows this variation, but I’d be very surprised.