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maintaining the maintainers? What impact has human factors research and intervention had on overall aircraft safety?
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maintaining the maintainers? What impact has human factors research and intervention had on overall aircraft safety?
In my experience duty time for personnel involved in maintenance has never quite been taken seriously. As you say we have come a long way in understanding the effects of fatigue, but the management of it seems to lie squarely on the shoulders of the individual and their ability to say 'no, I must adhere to duty times'. Duty times are put in place to support engineers' in ensuring that they can perform their job in a safe and effective manner and yet it is engineers' who choose to work outside duty times. So why do we seem to have the inability to follow the law? Is it a lack of understanding of why duty times exist? Company pressure? Financial reasons? Inadequate resources, i.e. manpower? The love of aircraft? In my opinion, a little of everything. Engineers have a special nature and take great pride in their work. When an aircraft goes tech they feel an overwhelming responsibility to get the aircraft back up and flying and prefer to see the job through to the end regardless how long this might take. Although their is a heirachy within the maintenance organisation engineers' tend to take control of their own working environment, meaning, they may be working an 8 hour shift, but if at the end of that shift they still have a broken aircraft they will decide themselves to stay or go. There is no single person to control duty times, if an engineer chooses to stay then the responsibility relies solely with him/her, and the company itself seems to follow the philosophy that an engineer has read the company procedures, they know the rules and they have chosen not to adhere, should anything happen. We are also very individualistic in nature in such that we do not function as a group, one engineer may say no to working outside duty times, but the next may not follow ensuring that there is always someone who is willing to work outside the scope.
Engineers' are taught about fatigue, told the effects, shown example of accidents caused by fatigue, and shown the law that governs allowable working hours, however without an effective fatigue management process which includes the monitoring of duty time engineers will continue to work outside the rules.
There have been many mid-air incidents and sadly, a couple of mid air accidents during my ab-initio days.
Personally, there have been 2 occasions that would have led to a disastrous ending if not managed well.
1. Back in 2006 when I was doing my VFR Navigation flight up North towards NZNP, I have planned to do a touch & go at NZWU on the way up. NZWU is not a controlled aerodrome in a MBZ. Weather information is available for NZWU through the AWIB. Therefore, the runway in use is determined by the pilot operating in the area.
As I approached NZWU, I got the weather and it was favoring the South facing Runway. I made my calls in the MBZ and heard nothing on the air so I just carried on my approach into NZWU as per planned. However, as I called overhead and joining left hand downwind for the approach, another aircraft called up and broadcasted that he was on the finals of the reciprocal runway for a touch and go before carrying on his journey down south. By then, I was already on the left hand downwind. I called for him to make a left hand turn upwind instead of his broadcasted intention to vacate via the right hand downwind (which was where I was coming in from). I did not get a response from him so I watched him as he did his touch and go. Hoping that he knew I was there from my broadcast and attempt to communicate with him, to my horror, he made a right turn and started heading towards me. I managed to space myself out on a wider downwind before carrying out my approach. When our aircrafts passed each other, it was near enough for me to see the shock on the pilot's face to see the proximity of our aircrafts.
A few things I learnt from this:
a. Airmanship - Always broadcast even when you think that no one is listening
b. Airmanship - Always use the runway the wind is favoring if it is an uncontrolled aerodrome. If you decide to otherwise, do broadcast your intentions
c. Communication - Listen out and not just broadcast for the sake of broadcasting.
d. Situational Awareness - Always know what the other pilot is doing and how it will affect you.
2. In 2007, I was returning from an IFR NAV on a Seneca into NZPM. We came in for Rwy 07 for the circling approach for Rwy 25. The circuit area then was active and there were about 2 other aircrafts in the circuit. I shot my approach down to 700' and broke right to circle left for Rwy 25 as requested by ATC. As I joined left hand downwind for 25, there was another single engined aircraft at 1100' ahead of me. Tower gave instructions to the other aircraft above us to make a right hand orbit at his position to allow us to land first since we were lower and will be faster than him. The pilot acknowledged the instruction of the ATC. However, as we continued to fly downwind, we saw that the guy did not make an orbit and instead, he started descending and turning left to join base for the approach. Immediately, we made a right turn and informed tower that we'll orbiting due to traffic closing in on us from above for the approach. Tower later made the pilot land for a full stop and we continued our approach after him.
Few lessons from here:
a. Communication - Always understand the instructions from ATC and not just read them back because it is the right thing to do
b. Situational Awareness - Always know where the other aircraft are even though you are under radar coverage
c. Situational Awareness - Always know what the instructions ATC gives you is about and not just follow blindly. ATC may have made a mistake or someone else flying or even yourself may have made a mistake.
It was one of my very first short-field takeoff trainings on Palmerston North Grass runway25. Grass runway at Palmerston North airport is very short, it is only about 600 metres long with a paved taxiway in the middle of it. The surface condition on the day was wet and soft as it had been closed for a while , however it was cleared safe to conduct a takeoff and landing on the day. On every takeoff, especially in a short-field takeoff a pilot is required to have a decision point where he/she decides whether to continue or abort the aircraft. This decision point during a short-field takeoff can be selected by selecting a point on the runway and the safe airspeed for the takeoff to be continued at the particular point. As the aircraft I flew on the say was PA-28, my decision point was at the paved taxi way at speed of at least 40 kt. I kept saying to myself that "I need to have at least 40kt passing the taxiway" This decision was shared to and agreed by flight instructor sitting next to me. I applied full power and the takeoff was commenced on a wet and soft Grass 25. As the aircraft was rolling, the airspeed did not increase as much as I expected from the past flight. It only increased slowly. As passing my decision point(taxiway), airspeed was still about 35kt. Without saying anything to the instructor, I decided the abort the takeoff, and quickly close the throttle to idle along gentle braking. The instructor was surprised by my sudden action, however he had no time to apply full-power again as the distance left to run was insufficient. He then helped me with more braking in order to stop the aircraft within the distance available as my braking alone was insufficient. The aircraft came to a fully stop within the grass distance, the nose wheel was sitting just at the end edge of the runway.
After the flight, I had a talk about my decision with the instructor. He mentioned that the decision was good, however it was very poor communication as I didn't say "ABORT!!!" and also insufficient braking applied when the decision was to abort. At least I should have told him my decision to abort before acting so. He also mentioned that if I had told him he would still be happy to continue the takeoff. And also when decide to abort the aircraft due to many reason, maximum braking should applied.
The big thing I learnt from this flight was that when aborting the takeoff maximum braking should be applied to stop aircraft within available distance. It was lucky that there was a flat grass surface after the Grass runway at Palmerston North. What if it was something else?? And also the effective communication between crew is always required, especially when flying with a flight instructor who is the Pilot in Command and has more experience in flying as at the time I only about 12 hours of experience.
AVIATION MAINTENANCE: STANDARD OPERATING PROCEDURES AND THE IMPORTANCE OF FOLLOWING THESE PROCEDURES.
Embedded as a customer within an overseas-based aviation contractor working on an aircraft avionics upgrade project, I observed and experienced multiple safety incidents related to standard operating procedures. Documented below are two examples which highlight the importance of following procedures, describe the consequences of not following procedures, and demonstrate poor communication within an aviation organisation. Arguably, these examples demonstrate defences preventing potential accidents.
INCIDENT 1: CAPTAIN YOUR TEST FLIGHT IS DELAYED.
During the flight testing program the aircraft was configured for a particular serial and dispatched by the contractor in preparation for flight. As a part of this standard procedure/process the contractor maintenance team was to brief the aircrew on the serviceability state of the aircraft (during the pre-flight brief). The brief included the following:
• Project installations which had occurred since previous flight,
• Maintenance and repair carried out on the aircraft since last flight,
• Long term acceptable defects to be carried on the flight,
• General servicing and replenishment information,
• And any other relevant information pertaining to maintenance on the aircraft.
On this occasion the brief was completed and it was announced that the aircraft was serviceable for flight. When aircrew pre-flight was complete the contractor produced its maintenance release form fully signed, the aircraft maintenance log book was signed and the aircraft was released for flight.
As the aircrew were strapping into their seat and the aircraft ladder was about to be lifted the contractor’s quality assurance lead wandered into my office and handed me some paperwork. The paperwork indicated that during the evening the nightshift maintenance team had carried out rectification on a long-term defect on the autopilot system. Further inspection of the paperwork suggested that after a re-wire of a connector in the autopilot system, no functional and independent functional had been carried out. These are standard maintenance procedures. The contractor who briefed the aircrew on maintenance made no reference to this autopilot work and in fact had no idea the work had been carried out over night by the other shift.
After a quick exchange of words with the contractor I immediately went out to the aircraft to explain to the captain that his flight was going to be delayed, and that he needed to sign the aircraft back to maintenance so the contractor could carry out the functionals prior to the aircraft flying. Of note, in 25 years of working in aviation maintenance it was the first time I had to prevent an aircraft from flying.
Potential Safety Implications
The safety implications of this maintenance error have the potential to be catastrophic. An example would be an incorrectly wired autopilot system has the potential to place the aircraft in an incorrect sense (attitude). A functional and independent function confirms the autopilot system operates in the correct sense.
• Lack of adherence to standard operating procedures.
• Poor communication between the two functional elements in the contractor’s maintenance team.
Human Factors Lessons
It could be argued system defences captured this error prior to the aircraft taxiing but in reality it was a matter of timing which allowed this error to be picked up. Equally it could be argued if there was a problem on engaging the autopilot the pilot's skills, expertise and SOP's would mitigate the likelihood of an accident. However, if this maintenance error remained latent and lined up with other active and latent errors, and defences were breached, then a major accident could occur (Accident Causation Model).
Two important lessons can be derived from this incident:
• Standard operating procedures are an important element in a safety management system. Procedures are put in place to reduce error and mitigate consequences of error so they should be followed, and this ethos should be followed in all levels of the organisation.
• Communication is an important aspect of a safety management system. It allows information flow from top/down and bottom/up. The positive aspects of good communication contribute to safety and efficiency. In this case good communication between the maintenance shifts would have highlighted the functionals were not carried out and the customer would have been fully informed that the work had been completed.
INCIDENT 2: SAFETY LOCKING DEVICES AND PROCEDURES.
During standard post-flight maintenance on the aircraft described in incident one, the contractor’s maintenance staff were required to follow the customer’s standard operating/maintenance procedures, and these were laid out in the form of work cards.
On this aircraft there are two hydraulically activated large doors on the underside of the aircraft. To make these doors safe there is a safety pin (locking device) which is inserted at all times on the ground which prevents the inadvertent or accidental actuation of the doors with the aircraft hydraulic systems powered on the ground.
In short on two occasions this procedure was not followed correctly and the safety pin was inserted incorrectly, and on both these occasions the error was made by the same tradesman. On both occasions the error was noticed by customer representatives and brought to the attention of the contractor’s line management. Of note, no ground safety incidents were raised for these errors because an easily accessible, non-punitive and anonymous safety reporting system was not in place, and if there was it was not communicated well.
In the weeks following this incident another procedural issue occurred with contractor’s staff which involved the application of external power to the aircraft without using standard operating procedures. On this occasion, one of the aircraft hydraulic systems was left on when power was applied and there were people standing in area where the doors close. If this error had occurred with an incorrectly inserted safety pin and incorrectly positioned door switch (a part of external power on check), an accident would have been inevitable. This tradesman’s failure to follow procedures was investigated as a result of this incident and she was given remedial training.
Potential Safety Implications
The safety implications of this error have the potential to be fatal. In short, if a person was caught in these doors as they were being closed they would be literally cut in half.
• Lack of adherence to standard operating procedures.
• Poor or lack of thorough training for the contractor maintenance team on aircraft type.
• The competence of the tradesman could be questioned.
• After discussing the incident with the tradesman he was hesitant about notifying his management of uncertainty or lack of confidence in carrying out the task correctly.
• Poor design on the aging aircraft which could allow the pin to be fitted incorrectly.
Human Factors Lessons
This incident highlights latent errors documented in the Accident Causation Model. Important lessons can be derived from this incident:
• Standard operating procedures need to be trained, followed and their use embedded in the organisations safety culture.
• Training to generate expertise is an important aspect to be managed in a safety management system.
• Building a safety culture with open communication is important in aviation organisations. A ‘rule with an iron fist’ type attitude has no place in aviation at all organisational levels. This would help to mitigate tradesman having fears of ‘putting their hand up’ when they are uncertain, uncomfortable or feel safety and efficiency is being compromised.
• The value in having an easily accessible, non-punitive and anonymous safety reporting system has a necessary place in aviation organisations to allow collection of data on near-misses, incidents and accidents. This will provide data for reducing error and mitigating error consequences.
• Redesign of the safety pin (locking mechanism) is a valid option.
Aviation Project Team Fatigue
Interestingly I work for the same organisation as others who have posted information on maintenance fatigue in this forum, and I would like to comment on an experience I endured while working on a project team.
The organisation I am employed with and its management are well known to employ insufficient manpower on project teams to save costs and this particular project was no different. The project involved the upgrading of the avionics systems on an aging, turboprop aircraft by an overseas based contractor. The project team to be discussed was the customer in this upgrade and our responsibilities involved:
• Maintaining quality assurance,
• Ensuring the project met the contract specification,
• Providing operational and engineering liaison with the contractor,
• Ensuring the basic aircraft systems (non upgraded systems) were serviceable,
• And to ensure my organisation’s standards and documentation were correct and complete.
My role was the lead flight line/hanger specialist on aircraft type in a small engineering and maintenance team with four members (2x engineers and 2x senior technicians).
Over three and half years the aircraft was subjected to a major upgrade to its systems followed by integration and test phase. While the aircraft was in the hangar it was regularly inspected and serviced while in preservation. Prior to the flying phase the aircraft was subjected to a comprehensive wake-up servicing plus functional testing.
As the customer, our under-manned engineering team was responsible to ensure we were ready to fly and all the documentation was complete by a certain date, and this dead line had been set under the contract. The final few weeks leading up to the first flight (Functional Check Flight) were hectic due to the significant amount aircraft documentation, recording and aircraft inspections required. In short, to achieve this task our team worked on average 14-18 hours per day and weekend work for over a week to achieve the deadline. The task was complicated by poor and slow documentation of the work completed by the contractor. In the end our small team met the deadline and the aircraft completed its post-upgrade flight with reasonable success, apart from a flight safety incident which was unrelated to any of the engineering teams actions.
This experience has left lasting impression for me personally of what not to do in aviation and as an aviation human factors manager. Our small team was physically and mentally fatigued after 4-5 days but we pushed on to achieve the task, with a ‘can do attitude’. Key fatigue issues experienced included:
• Making mistakes with the documentation (which were corrected),
• Lost concentration during inspections where I had to walk away at times to clear my thoughts,
• Behavioural issues (Short temper),
• General tiredness and malaise with degrading health and appearance,
• Observation similar issues with my fellow team members.
At one point in the process one of the engineering leads and I put our hands up to demand a break, which did occur but was still not sufficient to relieve our fatigue. We also requested more staff during this period but continually had replies suggesting there was no money to make this happen and no staff available to supplement the team. Operational staff observed and expressed their concern to management of the hours worked by engineering, but the reality was that meeting the deadline was more important, especially for the contractor. Eventually, during the flight testing program, our concerns were recognised and the team’s composition was increased. However, it could be argued the manpower increase was valid and still required at the later date but should been actioned prior to the start of flight testing.
From this experience I learnt the following lessons:
• Fatigue in aviation maintenance is a real threat. Fatigue has the potential to generate latent errors which may go unnoticed until errors line up to create an accident (See Accident Causation Model)
• As a human factors manager in aviation projects or any aviation maintenance operation it is important to ensure there is enough employees or time to allow careful management of employee health and fatigue. This approach will maintain safety and keep the operation more efficient.
• As a human factors manager in aviation maintenance there is a requirement to be aware and understand the risks of pushing team members to their extremes and in this circumstance there was no true requirement. Note, it must be understood in some organisations like the military, there may be a necessary requirement to work to extremes (although it is discouraged).
• As a member at all levels in aviation organisations, and in the interest of maintaining safety and efficiency, there should not be any hesitation in notifying management of unsafe circumstances and practices.
• There is no place for the ‘can do’ approach in aviation if it has negative consequences on safety and efficiency.
• I would like to endorse the lessons learnt on fatigue described by Charger007 and Robere in this forum.
• SAFETY is a key requirement or outcome in any aviation maintenance or project activity so contract deadlines and financial drivers must NOT take precedence.
Another recent event which continues to add to my (hopefully) growing knowledge and experience base was the occurrence of a GPWS warning of “Caution Terrain” followed by a further warning of “Terrain Terrain, Pull Up” whilst on the final portion of a Non Precision Instrument approach when still under Instrument Meteorological Conditions. I was the flying pilot and as far as both I and the Captain could establish, was on the correct profile for our distance with speed and decent rate in accordance with company SOPs and the aircraft in the correct configuration (the tower controller was able to also confirm our bearing from the airfield was consistent with what one would expect of an aircraft conducting such an approach but as he had no radar, he could not verify our height).
When carrying out competencies checks, you expect emergencies and abnormal events to occur and so are ready for various things to happen. During a normal shift when such an occurrence presents itself, you definitely notice the greater time it takes to register, process and act on the event. Many studies have examined and shown this over the years, with reaction times of upwards of six seconds noted in pilots responding to a situation (George, 1996). I can recall there being a very real “what is that” moment before processing it, thinking that we were exactly where we should be so why is it going off before calling for a Go around/missed approach and climbing the aircraft away. We tracked towards a hold at safe altitude, checked several aircraft systems, confirmed we had the correct QNH set before trying the approach again for a safe and uneventful landing.
De-briefing the event afterwards I found it interesting that both the Captain and I internally (VERY briefly!) thought about ignoring what was probably a spurious warning before assessing the situation (bearing in mind, such thoughts are happening in a mere matter of seconds), complying with safe practices/SOPs and returning the aircraft to a safe height. It would seem the terrain awareness that my company conducts worked. With everything going on we still both thought briefly about a video all our pilots are shown concerning a 747 operating into Malaysia where the crew descended below the minimum safe altitude, ignored a GPWS warning because of faults the system may have had, only to fly into the side of a hill with the loss of fours lives (see N807FT Crash). False alerts may happen for various reasons and as tempting as it may be to ignore them sometimes, it still pays to listen to them and act accordingly; one of them might just save you one day.
George, F. (1996, March). Rejected Takeoffs. Business & Commercial Aviation, 76-81
During one of my duel CPL nav training exercise, I was flying with my instructor over the eastern part of the north island heading back to palmy. I remeber it was a day with clear blue sky but medium to strong westerly winds. All of a sudden, we encountered heavy turbulance and both of us was not straped tighly enoguh on the seat and was thrown around in the cockpit, bumping our heads into the ceiling. I immeditily applied full power and climbed as I suspected that the turbulance was casued by the ranges below which we started to fly accross, altho we had to bust the airspace, but to me it was an unforgettable experience.
This incident happened on my 2nd solo. I was doing solo circuit practice at NZPM (Palmerston North) with very limited flying experience, approximately about 15 hours. My intention was doing 3 circuits at Palmerston North in order to practice my flying skills. The first circuit was normal. Everything was usual. During the 2nd circuit I was told that: “Due to the arrival of an Air NZ flight, after touch and go continue climbing maintain runway heading until further advised.” Therefore after the “touch and go”, I was climbing on runway heading and waiting for calls from ATC (I thought I was doing as exactly as what tower asked me to do). However, I did not know that I should level off at 1100ft (circuit altitude and NZPM). The traffic around Palmerston was a bit busy, and I did not receive any radio calls from tower for a few minutes. Eventually when tower called me again I got asked to descend immediately and I noticed my altitude was almost at 2000ft (went into Ohakea controlled airspace without clearance). After that I descend to 1100ft and continued a normal circuit with a full stop landing.
What I learned from this incident is that a clear and good understanding of airspace is very important, and it can help understand the instructions obtained from ATC. Secondly, any time if unsure about any clearance, do not hesitate to ask. A confirmation on clearance is better than doing something wrong.
I was the First Officer rostered on an afternoon shift which involved two return trips over the same leg from a regional New Zealand destination (my home base) to Wellington and back. Our first leg to Wellington was uneventful and upon landing in Wellington we had a planned aircraft change to collect a different company aircraft and return to our point of origin. Upon entering our new aircraft and reading over the aircrafts defect list (referred to as "the book"), we learnt the aircraft had an issue that rendered the Flap system unserviceable. This meant the normal performance figures we would usually use (that assume the use of Flap) were incorrect. We were then forced to delay the flight while we calculated our new figures which included new speeds and new restricted Takeoff and landing weight limitations.
We departed late and enroute learnt the Weather at the destination was now marginal for our operation. A change the company made just prior to me joining was the inclusion of a threat briefing before takeoff and again prior to commencing descent. Often we do not perceive there to be many real threats but today we were able to identify several. Without Flap, our approach and landing would have to be at a higher speed than normal and the actual landing itself involves a slightly different technique to prevent a tail strike. We also had the threat caused by the marginal weather and the very real possibility of a diversion being needed and our finite fuel state. I was the Flying Pilot during the approach and still fairly new to the company (another threat) although the Captain was one of our most experienced pilots (hopefully threat mitigation). We briefed that on the approach I would continue flying by reference to our instruments and in the very narrow window of time in which we had to see the runway, if the Captain could see the runway and I could not, he would take over and complete the landing. Having identified all our threats and hopefully put in place as many strategies as possible to reduce them we continued and managed to make a safe and uneventful landing.
Our next sector back to Wellington was again uneventful and having made up some time, we managed to turn around and depart at something resembling on time for our last sector back home. Enroute we received news that the VOR at our destination was now not working and we would be required to conduct a GPS approach. The threats present earlier were still all relevant and adding to the list was now the fact we had to fly an approach that, although we were familiar with, we do not do as often as some others so consequently had less residual mental capacity to spare. Fatigue was also starting to set in as this was our fourth sector and we were fast closing in on nearly 4.5 hours flying time in challenging conditions. We ended up burning 10 minutes of fuel when we had to hold and wait for the weather to improve at our destination to a limit where we were allowed to commence the approach.
Finally the weather gets to a point where we can try the approach. This was the Captain's leg so I was the Pilot monitoring which required me to make radio calls and call pertinent height and tracking information on the approach. As we commenced the final portion of the approach (still in cloud) our GPS system failed. This was our sole source of navigational information so now we are effectively pointing at a hole in space, not knowing where we are or we are going. Instinctively and immediately the Captain called for a missed approach and attempted to gain height as quickly as possible. We both had the benefit of local knowledge and knew that even if unsure of our position, if we could gain a couple of thousand feet of altitude, terrain would not be an issue and we could then assess our situation. Whilst this was going on, as the Pilot monitoring, I was following company recommended procedure to try and re-establish GPS navigational information. With that achieved and at a safe height, we discussed our options and decided that a diversion to our alternate aerodrome would be prudent and that we would not use the GPS for the approach in case it failed again.
We were however not yet done! As we were about to commence the approach at our alternate, we were informed it was no longer suitable! This required a further diversion to another nearby field which was still open. This was entirely unexpected and required us to both dive into our books and find the new relevant approach plates. Under control again, the Captain comments that, "I don't like this, the Swiss Cheese holes are lining up." I could only agree. Finally however, we managed an uneventful landing, at an aerodrome we never expected to be at, after 5 hours flying over a very long day.
From the shift I took away several things. With everything going on, the Captain still kept up with and made sure the cross cockpit communication continued. He had 25 years in the company to my 3 months but emphasised I was to speak up if I saw anything or felt he had missed anything and to not assume he would get it right because of all his experience. We decided to carry extra fuel out of Wellington to give us plenty of options and time to make decisions which paid off greatly. The company decision to introduce the threat briefing to make sure crew are aware of risks present and discuss the implications of those risks. Thinking about things though, especially after the Captains reference to Swiss Cheese, some of the company actions may have actually introduced more threats to the operation. Although the aircraft will fly safely without flap, many companies would not consider having a flight depart with no flap and passengers onboard a prudent decision. My company considered it to be an acceptable option rather than cancelling the flight. On it's own it is not a significant threat but combined with other factors, it could provide enough of a distraction to allow something else to 'slip through the net.' Through this example (although we had many other things going on) I can see how decisions made by management could potentially flow through an organisation and introduce threats at an operational level that might one day lead to a failure in the last line of defence and that final Swiss Cheese hole lining up. I witnessed on this shift how important knowing about and managing threats can be and it was an invaluable lesson.
Regarding the above incident and whether it was a result of you “counting the wrong plane” or due to a breakdown in the controller’s situational awareness; while both explanations are feasible, I won’t launch into any conjecture about who was at fault.
What is far more concerning is the apparent lack of aerodrome control in the above incident. Any time there are two or more aircraft in the circuit, “ATC should advise the pilots of their position in the landing sequence and of the aircraft immediately ahead of them, including an instruction to follow or position behind the aircraft concerned” (CAA Advisory Circular AC172-2, 2.1.11).
E.g. “ABC continue approach number 3 for Runway ##, follow the Cherokee on left base”
A pilot’s acknowledgement of instructions to “FOLLOW” another aircraft is the acceptance of visual separation from the preceding aircraft, and the pilot must advise ATC if visual contact with the other aircraft is lost or cannot be maintained (NZ AIP Vol.1, ENR 1.1 – 28).
Your “traffic in sight” call seems ambiguous if you were given no detailed information on the preceding aircraft (i.e. aircraft type and position), and should have been questioned by ATC.
If you ever experience any similar incidents involving a loss of separation (and hopefully you don’t!), then please ensure you also report them through the proper channels. The subsequent investigation should help strengthen the safety system going forward.
During my CPL Nav training, I was sitting in the PM seat (co-pilot) seat with one of my class mate and we are heading to wanganui from new plymouth, on near half way I have discovered that our ammeter was reading zero, which means our alternators aren't working and we are running on batts. (in the old PA28 airplanes the batt is only able to last 1hr before it runs dry, and we have no idea how long it was on batt before). we quickly notifly the ATC(altho we are not in controlled airspace), all called ops, while the pilot in command is flying the plane and refering to QRH, we even left our cell phones on just in case, but lucky for us after a while using limited instrments we are able to land back into palmy with our radio still on
the lesson I learnt here is to always to have a back up plan(like we had our cell phones on just incase) and always do ur checks
I remeber once during my early stages of training in palmerston north, I was on a solo practice flight to the southern training aera south of palmerston.
When I completed my practice and wished to join the palmerston circuit patterm to do some touch and goes (a practice of landing and take-off skills), before a full stop landing. I was cleared for the circuit number 3, so I started to look for the 2 planes in front of me. (At that time I was trained in the PA28, not the DA40 we hav now with the flash as TCAS system), there was one plane on short finals and about to land and another on base. so I called the traffic in sight and position myself number 3. But just befor I turned finals, another PA28 flew past right in front of me, with distance (eye measured) close than 100ft!! The ATC did not say anything so in order for me to have enough distance, I gave myself space by deploying flaps and doing big S turns on finals for the "acctual number two" aircraft.
Till this day Im not sure weather it was me counting the wrong plane or was the ATC's miscount of planes.
Hi, I´m working as CRS for Icelandic company, under ICCA and UK CAA Regulations. does this Duty time also rule there? or do you know where I can find Max duty time for them?
During a normal take off on the seal at Palmerston North the plane started to head left towards the side of the runway quite alot. I was with an instructor at the time who took control and carried out the take off. After confirming with my instructor that i had not been using left rudder on take off he requested to re join and land back at Palmerston North to see if it was a fault with the aircraft. My instructor carried out a slower than normal landing on the grass runway and once we landed the plane continued to head left. We taxied back to base and later an engineer found that the left brake had been sticking causing the plane to head left. This was a good lesson in how to manage unusual aspects of flight and turn back if it is the safest option
During the initial stages of my PPL navigation flights I was doing a nav flight from Palmerston North to Wanganui with a touch and go in foxpine. After take off in foxpine I headed out to the sea to track the coast to WU. About 20 minutes after take off I needed to do a tank change and carried out standard tank change procedures and was filling in the fuel log when the engine cut out. I was quite shocked but started running through the immediate actions check list and set the aircraft into a glide and picked the beach as an appropriate landing site. After switching back to the other tank the engine started about 4 or 5 seconds later and i was able to return safely to Palmerston North. On inspection they found that the spring in the fuel selector had broken and when I changed tanks the selector went through to off instead of left tank. This was not picked up in run ups as I had started the plane on left tank and during run ups it is procedure to change tanks which I did and therefore I had not tested turning it to the left tank. This was a good lesson on how to work under pressure
During my PPL navigation flight block I was doing a solo flight from Palmerston North to New Plymouth with a touch and go in WU. Shortly after take off from WU the top latch of the door (Pa-28) slipped open and there was a great noise in the cockpit. I managed to get it closed again but in doing so lost some height and lost my position. I spent about 10 minutes running through a lost procedure to get my position and had to alter heading to get back on course.
On return to Palmerston North my instructor questioned me about how I managed to get so far off track as he had been watching through spider tracks. I explained to him the situation and he made the suggestion that I could have turned back to WU and landed and fixed the door on the ground, this would have taken more time but would have eliminated the time spent doing the lost procedure and would have ultimately been the safer option. Because of my lack of flight experience this had never crossed my mind at the time.
This happened to me when I was at the arrival position. I had an aircraft, let’s call it AK5, established on 15nm finals runway 20R, at 2500 feet. I had another arrival, AK6 maintaining 4000 feet, was heading southerly, no. 2 to AK5. Tower had requested for at least 8nm spacing between the 2 traffic to send out a departure. My plan was to continue AK6 on a southerly heading, cross the localiser and make a left turn to be positioned behind AK5. In that case, there will be less turns for AK6 and I will be able to achieve my 8nm spacing. When AK5 was at 12 nm finals, AK6 was next to it, on the left. I issued an instruction for AK6 to turn left to heading 290 degrees. AK6 replied “left heading 290, AK6”. Next, I observed that AK6 was commencing a right turn. Immediately, I went back to AK6 and queried if they are turning left. AK6 sounded a little apprehensive and replied “Affirm, you said right heading 290?”. Since AK6 was already on a right turn and there was no imminent danger as both traffic were vertically separated, I allowed and instructed AK6 to continue on the right turn. Subsequently, I issued an instruction for AK6 to descend to 3500 feet. Pilot read-back and I was not able to make out if the pilot had said 2500 feet or 3500 feet. I repeated my descend instruction. This time it was clearer and I was satisfied that the read-back was correct. Seconds later, I observed that AK6 had busted 3500 feet, mode C showed AK6 at 3300 feet and AK5 was just 1 nm to his 12 o’clock at 2500 feet. I was flustered and immediately transmitted with urgency to AK6 that the last altitude clearance was 3500 feet and to stop descend. AK6 was very quick to respond and immediately climbed back to 3500 feet. That was really closed! Without hesitation, I requested for a relief and reported the incident to my supervisor. ATC played back the radio transmission to check if there were any oversights that lead to the level-bust occurrence. It turned out that instructions and read-backs were all correct, the error was on the pilots’ execution of the instruction.
I had a lengthy discussion with my superior. Although the error was committed by AK6, nonetheless, there were some pointers that I should be mindful of in future.
Firstly, my superior highlighted that from a human factor's point of view, it is only a natural human instinct to take the shortest turn. From a southerly heading to heading 290, a left turn would mean 250 degrees turn and a right would only be 110 degrees. To avoid such misunderstanding in future, I should highlight my intention to the pilot if it is out of the ordinary. Phraseologies such as "Turn LEFT, LEFT heading 290" or "Turn Left heading 290, I say again, LONGWAY ROUND, turn left …" should be used to accentuate the intent for the pilot to expect to execute a wider turn.
Secondly, on hindsight, I should not have issued the descend instruction to 3500 feet from 4000 feet. It was observed that the pilot already committed 1 mistake even though the read-back was correct and that the pilot appeared to be uncertain when queried. It is in the best interest of safety to remain status quo till both the aircraft are on a diverging heading. Although we can argue that it is not wrong to descend AK6 to 3500 feet as the 2 traffic would still have the minimum required 1000 feet separation, there is a possibility that the pilots may commit another mistake as they may not be in the right frame of mind after committing the first mistake. Perhaps they are going through or trying to recall what had just happened a minute ago. We never know what is happening in the cockpit. Whether the crew are in sync or not with each other that caused all parties to acknowledge yet execute something else is hard to know. On the ground, when we encounter a close call situation, we can always ask for a relief or will be relieved immediately. In the air, the pilots have to cope and deal with the situation. So, to reduce the rate of error, it would be better to maintain AK6’s altitude at 4000 feet until the required lateral separation is achieved with AK5 before issuing another instruction.
I felt that, in this brief 1 minute occurrence, what could have lead to AK6 taking a shorter turn and descending through the cleared altitude of 3500 feet could also be due the close proximity to the aerodrome. It does not make any sense to the cockpit crew to turn away from the airport seeing how near (10nm from touchdown) they were to the airport. They were not aware of ATC’s intention to turn away and provide a bigger spacing to facilitate a departure.
So, after the discussion, we both agreed that the take-away lesson from this incident was to always state our intentions to the pilot. In this way, the cockpit crew will be aware of the bigger picture (better situational awareness) and they will be able to act accordingly. After all, they are also the expert of the system. We cooperate with each other to provide a safe, orderly and efficient air travel.
A266 contacted ATC and reported maintaining FL270. ATC acknowledged and replied "M2661, roger, maintain FL340". A266 then replied "A266, Roger, maintain FL340".
In this occurrence, ATC had mistaken A266 for M2661. This is a case of flights bearing almost similar sounding callsigns being mistaken for another. Here I would like to stress again that listening attentively is very important. We must always be extra vigilant when dealing with similar sounding callsign and also the read-back from pilots. The A266 pilot also did not realise that ATC had instead called M2661 and not him, yet duly acknowledged the reply from ATC.
With flights increasing constantly, especially in the Asian region, it is unavoidable that there are callsigns with similar numbers. Similar sounding callsigns are a potential threat. A more permanent solution is to feedback to the airlines so that they can work out some arrangement such as changing the callsigns or reschedule the flight time.
In the meantime, to mitigate the potential threat, we can
i. Intentionally repeat the callsign.
Example, “A266, I say again A266…” Either the pilot or controller can make use of this method to highlight the callsign to the other party.
ii. ATC could also highlight to the pilots that there are flights with similar sounding callsigns on the same frequency. This is to indicate to the pilot to be more attentive when listening out.
iii. ATC or PIC can initiate a temporary change of callsign.
Example: A226 can temporarily be known as A266D until the other traffic leaves the frequency or area of conflict.
Aircraft was maintaining FL370. Pilot requested via CPDLC to climb to FL390. Due traffic, controller was unable to approve the request and thus replied “maintain FL390”.
In this occurrence, the controller had meant to reply “maintain FL370” but did not realise that he had typed FL390, the requested level. In my opinion, a better approach to handling this would be to just use phrases such as “Negative” or “Not approve” only. This will not cause any misunderstanding in the clearance and pilot will maintain their cruising level. It is a more positive control and pilot would easily know that their request has been rejected.
In both the occurrences, ATC had used the phrase “maintain FLXXX” and both the flights actually left their cruising levels. In my opinion, since both the aircraft were already maintaining their respective levels, the pilot should not have initiated a climb. The instructions from ATC were not coherent. PIC should query ATC’s instruction – “Confirm to climb to FLXXX?”or “Confirm to maintain FLZZZ?” This will trigger ATC to re-examine the instruction issued and would then realised that there was a mistake made on their part. By just climbing without authenticating the discrepancy may jeopardise the safety of other traffic within the vicinity.
Today, whenever I hear any controller talked about what had happened when they were on position, I tend to analyse objectively. Some say I am paranoid. I choose to believe that I am now made more aware after embarking on this Massey programme and especially after taking this paper which requires me to contribute to aviation knowledge. I try to deduce what has gone wrong and is there anything that I can learn and share with others so as to enhance a safer and better working environment.
This was told to me by my colleague from a training aerodrome during one of our informal chats. I thought this was something I could share as it was a case of lacking in situational awareness and perhaps the instructor’s haste to finish his job as soon as possible.
Summary of Events
A first time student solo (SS1) had just touchdown and was zigzagging on the runway. Seeing such a situation, ATC instructed the succeeding training flight (T1) to execute a go-around. Instead of just following ATC’s instruction, the instructor interjected and requested for a landing as the student need to go for a subsequent solo. ATC was a little annoyed and advised it was due to the SS1 still on the runway. T1 acknowledged, dutifully and respectfully carried out a go-around. T1 landed safely on the next approach, student went for the subsequent solo and the instructor proceeded to the control tower to observe. When the instructor reached the control tower, he started to discuss on the need to go-around earlier. ATC was a little exasperated and asked the instructor whether he saw the SS1 trying desperately to straighten the plane on the runway centre-line? The instructor was a little embarrassed and tried to explain his side of his story – that he happened to be concentrating on the equipment in front of him and was not observing what was going on. ATC was not amused and rebutted that he should be looking out as not only was it a visual flight; this is also a training aerodrome whereby anything could happen at the very last minute. As such, he must be aware of the environment at all times and be prepared to execute any instructions issued out by ATC without delay.
Pointers to share
1. When flying under visual rules, a pilot should be aware of what is happening around the environment, even more so when one is an instructor. He must be prepared to take over the control when the trainee fails.
In this instance, the instructor clearly showed that he is lacking in situation awareness and was not performing his duty as a responsible instructor. Perhaps he was complacent, overly confident and trusted that the trainee would do the right thing seeing how this was a pre-flight to first solo.
2. Pilots should not always question ATC’s decision unless safety is deemed to be compromised. Otherwise, carry out the instruction first and query on the reasons later. Things could happen so fast, with you asking and not acting upon the instruction first may lead to an undesirable state of event.
In this case, ATC was obviously concentrating and getting ready to spring into action in the event that SS1 veer off the runway. ATC was planning the follow-up actions like coordinating with other agencies for the rest of the training flights that are still in the air to hold or divert to other nearby airfield in the event the runway becomes unavailable.
3. ATC has a bigger and fuller situation awareness of what’s happening within the vicinity of the aerodrome. Therefore, as an Air Traffic Controller, we should be patient and forthcoming in giving traffic information or reasons for a go-around even in a training environment. We should not assume that all pilots will see, think and know the same as ATC.
4. Perhaps, as pilots they too should have the foresight to anticipate and remember that they are not the only ones flying or needing assistance and guidance. They must be magnanimous enough to appreciate the bigger picture too as air safety is equally important to them.