The pilot of a light aircraft is accelerating down a runway in southern England when the plane starts moving to the left. Trying to avoid a runway excursion, he rotates the aircraft early and before reaching a safe flying speed.

We speak with AAIB Senior Inspector Emma Truswell about this incident and the findings from their investigation.

Also joining us is Paul Tedder from the CAA’s General Aviation Unit who covers the safety guidance around take off decision making and pre-departure briefings.

Reports and resources mentioned in this episode:

AAIB investigation to Europa XS, G-REJP

Clued Up: Rejected takeoffs (CAP 2510)

CAA Standards Document 14 (A): Class, type and instrument rating skill tests and proficiency checks

CAA Standards Document 19 (A): LAPL and PPL Skill test (Aeroplanes) policy and guidance for applicants and examiners

The Skyway Code

Training Comm 2019

Voiceover 0:17

Welcome to CAA Safety Files podcast

Nathan Lovett 0:30

Hello and welcome to the CAA Safety Files podcast from the UK Civil Aviation Authority. I'm Nathan Lovett from the CAA Communications team and in this series we look at occurrence, incident or accident reports that have been published throughout the different areas of the UK aviation industry. Each episode focuses on a different report, we look at what can be learned from it, and hear from aviation experts who help explain the relevant safety guidance. In this episode we're going to be discussing takeoff decision making, so the factors that can lead to a go or no go decision about whether to continue with the takeoff roll or whether to reject the takeoff. We're going to start by hearing about a recent incident report published by the UK Air Accident Investigation Branch or AAIB that has highlighted takeoff decision making, rejected takeoffs and departure briefings. I'm joined now by Emma Truswell from the AAIB, so we can hear what happened and learn from the findings from their investigation into this incident. So Emma, thanks very much for speaking with us. Can you start please by telling us about your role at the AAIB and your background in aviation?

Emma Truswell (AAIB) 1:29

Hi there. My name is Emma Truswell, I'm a Senior Inspector of air accidents. at the Air Accident Investigation Branch which is the UK's state safety investigation authority for aviation. Our remit is to investigate accidents and serious incidents with the intention of preventing reoccurrence. I joined the AAIB six years ago. My background was in educational psychology research and then I trained to become a pilot. I worked both in general aviation and then was an airline pilot for 11 years before joining the branch. I still fly with a UK operator and also have the opportunity to fly light aircraft as part of my role as an inspector.

Nathan Lovett 2:05

Thank you and what was your role with this particular incident and the investigation that followed?

Emma Truswell (AAIB) 2:09

I was the inspector who carried out this investigation on this Europa XS aircraft G-REJP, which experienced a runway excursion during takeoff.

Nathan Lovett 2:19

Please can you talk us through what happened in the incident?

Emma Truswell (AAIB) 2:21

A significant left yawing tendency occurred during the aircraft's takeoff roll. This resulted in the pilot rotating the aircraft before a safe flying speed had been reached in order to prevent a lateral runway excursion. This probably caused the wing to stall and the aircraft struck a raised earth bank. The report considers rule based takeoff decision making, rejected takeoff considerations and methods for self briefing those items before departure.

Nathan Lovett 2:47

Great. Thank you. You spoke to the pilot during the investigation. What did they tell you about the incident?

Emma Truswell (AAIB) 2:51

Yeah, the pilot reported that after applying full power to depart from this Nuthampstead airfields grass runway 05, that the aircraft yawed slightly more than usual to the left. He countered that with right rudder and brake expecting that the rudder would compensate for the yaw as airspeed increased. However later in the takeoff roll even with full right rudder and right brake applied the aircraft began diverging off the left side of the runway surface.

Nathan Lovett 3:16

The report mentions that the pilot reached a critical point as he neared the takeoff speed. What did you learn about those moments as he accelerated on the runway?

Emma Truswell (AAIB) 3:24

Yeah, the pilot described a critical point whereby wishing to avoid damage related to a runway excursion, but with the aircraft nearing but not quite at its takeoff speed, he stopped applying right brake and rotated the aircraft into the air. It became airborne briefly but touched down adjacent to the runway and then struck a raised earth bank and he hadn't previously considered rejecting the takeoff.

Nathan Lovett 3:47

And what do we know about the pilots experience?

Emma Truswell (AAIB) 3:49

The pilot had held a PPL since '88. He said he habitually self briefed certain aspects of a departure beforehand like what he would do if the engine failed after takeoff for example, but he could not recall any training he might have received on takeoff decision making, rejected takeoffs or specifically briefing those prior to departure. He'd owned this particular aircraft for around one month and most of his flying experience was on a different type. The Europa is considered by some to have challenging handling characteristics in moderate crosswind so the report discusses the benefits of pilots identifying key differences between a new type and what they might be used to.

Nathan Lovett 4:27

So the AAIB interviewed PPL holders, PPL flight Instructors and Examiners during the investigation into this incident. What did you learn from those conversations?

Emma Truswell (AAIB) 4:36

These conversations indicated that training and awareness of rejected takeoffs and related takeoff decision making was variable. Several long term PPL holders said they couldn't recall their initial training in those areas nor had they covered them in subsequent refresher training. All of the Instructors we spoke to indicated that pilots are commonly focused on getting into the air rather than considering the takeoff roll itself when preparing for departure. One Flight Examiner said that in his experience rejected takeoffs were one of the most commonly repeated test items mainly relating to the decision making aspect of the procedure. And one Examiner suggested that Flight Instructors may benefit from more knowledge in these areas. We talked to one pilot training organization who developed a structure for decision making during the takeoff roll. This involved early in the takeoff roll checking things like engine and airspeed instrumentation and runway tracking and making a clear stop or continue decision. Another training organization had produced an aide memoire for their pilots to use when briefing a departure which included nominating a decision point on the runway and specifying what their actions would be in either the stop or continue events.

Nathan Lovett 5:45

And the report on this incident mentions several guidance publications and resources for pilots that relate to emergency procedures. Please can you talk through what the report says in this area?

Emma Truswell (AAIB) 5:54

Well, we looked at a number of publications the CAA's Safety Sense leaflet on aeroplane performance mentions identifying a runway decision point for each departure, and warns pilots against inadvertently being go minded during takeoff to the exclusion of considering other things. Regulatory documents show that rejected takeoffs are a mandatory part of relevant skills, tests and proficiency checks and the CAA's Training Comm guidance leaflet includes advice to Examiners on how to test that element. It suggests using refresher training is an opportunity to address common training issues and encourage Instructors to promote using takeoff briefing structures and threat error management techniques. Threat error management is where a pilot thinks ahead to identify threats and specifies often during the briefing, how they will avoid or manage any resulting errors. Various leaflets and academic papers discuss pilot decision making in terms of the skill rule and knowledge module, which represents a continuum of the amount of conscious thought required by a response. Skill based responses are highly practiced and automatic in nature therefore require little conscious effort. rule based responses require more conscious effort. For example, if a problem is x, then perform action y. The paper we looked at described these as pre packaged units of behaviour which are released when the appropriate rule is applied. Knowledge based responses are almost completely conscious. For example, when a beginner performs a task or an expert experiences a novel situation. Take off decision making is particularly suitable for this simple rule based structure because decisions and resulting actions must be clear and prompt. Given that an abnormal event during takeoff would be novel for most pilots, a rule helps to avoid an unreliable automatic response while also reducing the conscious effort required by a knowledge based response.

Nathan Lovett 7:41

Great, thank you for explaining that guidance. And what are the findings from the AAIB investigation into this incident?

Emma Truswell (AAIB) 7:47

Overall, the investigation concluded that the accident was caused when, in order to avoid a runway excursion, the pilot rotated the aircraft before a safe flying speed had been reached, probably causing the wing to stall. Although the cause of the left yawing tendency was not established the report highlights the benefits of structured self briefing before takeoff to assist with effective decision making and prompt action in the event a takeoff does not proceed normally. There were a number of effects present during the takeoff, which would have contributed to the left yawing tendency. For example, propeller and crosswind effects on the grass runway. The investigation did not establish if there had been a technical fault with the aircraft. It touches on the benefits of pilots reviewing the characteristics of a new type and identifying any differences with what they might be used to. These can be considered in a threat error management context. For example, it can be beneficial to use more conservative operating limits for example crosswind component when gaining experience on a new type. Regulatory guidance and relevant academic papers confirm that a simple rule based structure for decision making, like used in commercial aviation is particularly useful for the takeoff roll during which decisions and resulting actions must be clear and prompt. For example, in the accident takeoff, the example structure used by one pilot training organization we consulted would have resulted in the accident takeoff being rejected because the aircraft was not tracking the runway centreline and because of a lack of acceleration. The likelihood of a successful outcome may be further increased by threat error management styles of self briefing that decision structure and relevant responses. This might include actively considering the possibility of stopping, as well as continuing the takeoff and consideration of things like a crosswind or wet grass and the location of a suitable decision point on any given runway. Refresher training presents an opportunity to brief and practice those items and perhaps use threat and error management style briefings. As a result of this accident, the CAA produced an article in its Clued Up magazine about takeoff decision making and rejected takeoff considerations in general aviation, which I understand is now available. The CAA has stated that it intends to explore other methods of promoting that guidance and new ways of engaging with the general aviation flight training community in this context.

Has the AAIB investigated other accidents that have highlighted decision making?

Well, there's an element of human decision making in every occurrence, so in that sense, yes. Takeoff decision making does have certain unique characteristics and related to that we have recently published a report on a PA 42 aircraft which experienced a runway excursion during a rejected takeoff. The registration for that one is G-LAMI. However, overall, the ideas behind rule based structures and self briefing and threat error management techniques serve as useful tools which can be applied in many different circumstances to improve safety.

Thanks very much for your time Emma, and for talking us through this report.

You're welcome. Thanks very much.

You're listening to the CAA Safety Files.

We're going to look now at the safety guidance and resources that are mentioned in the AAIB's report. The incident that we just heard about relates to general aviation, also known as GA or recreational flying. And joining me now to help explain everything is Paul Tedder, who works here at the UK CAA, in our general aviation unit. So welcome, Paul, thanks for being here. Please, can you introduce yourself and the type of work that you're involved with?

So my name is Paul Tedder. I'm a Flight Standards Officer in the general aviation unit here at the CAA, I started off in policy in the GA unit about five years ago. And since '20 I then moved into the flight inspection. So I'm one of the flight standards officers that carries out inspections and has oversight of certain GA operations and it includes generally all of GA operations, the flight operations side of it, those that aren't registered operators. So the private individuals, also the operators that fly ex military, Part SPO, which is specialized operations, parachuting, skydiving, aerial photography, and the general just pilot hiring an aircraft from flying schools that still requires oversight. And that's part of my role here.

And you're a pilot yourself, is that right?

I am yeah, I've been a GA pilot since '10. So we're probably going into the 13th year now of holding a PPL.

And you also fly commercially?

Yeah, I fly commercially as well and I've flown commercially, for around two years now.

We've just heard from the AAIB about the incident and their investigation into it. And you've read the report that they published? Is there anything particular that stood out to you about what happened?

There was a few things, especially from the report. The pilot was, well, in my opinion experienced in GA terms, quite a lot of hours. And the pilot recognized that something wasn't quite right but continued. And I think in the pilots own words passed a critical point on the takeoff roll, and still continued on. So that was really the highlight for me. It was just the fact that because he knew it wasn't quite right, possibly the decision making wasn't there at a time to sort of understand ok, what are my options here? And that obviously comes down possibly to a lack of pre briefing. You've done this thousands of times, hundreds of times, and you're not expecting something to go wrong, because you're so used to it. And when something does, you get that startle effect, and that can eat up crucial seconds.

As a pilot yourself have you ever found yourself in a similar situation to this one and have you ever decided to reject a takeoff?

Yeah, I've had one that that I can think of in GA flying, where I was not under pressure to undertake a flight. I just wanted to get airborne. I had plans for the day, and I needed to get there. So I had lined up on the runway saw the weather, the weather wasn't the best for the day, but I'd lined up started my takeoff roll then just probably about halfway through the takeoff roll the weather, in my head, I was like, no, the weather ahead in the climb out path was not good enough for me. So I did reject it, slowed down. For me, it was quite a long runway so I had plenty of time on this one. But in my head I hadn't planned to reject the take off until about probably a year or so ago in GA flying. I've never planned on ever rejecting, never thought about it. And ever since then it started in my head. I now try and pre brief myself. Okay, what am I going to do if I'm not at this point of this part of the takeoff roll, I will then have that sort of cutoff point or critical point in my head of I need to stop here. It's safer to stay on the ground than actually to fly. On that occasion it definitely was safer to stay on the ground.

And with the situation that you just mentioned where you made a decision based on the weather ahead. Did you have a predetermined point in the takeoff roll where you'd planned to make a go or no go decision?

No I didn't. It was all just a quick, really instant decision. I was already hesitant on the day I think I wasn't newly qualified. I was probably current in terms of the requirements, flying school requirements, at this time I was hiring from, but current in my head no, I hadn't planned anything. I had my plan for the day, I was gonna stick to it. I'd never until this point really though oh, what am I gonna do if I don't take off. In my head I was always going to be I'm gonna take off, I'm gonna go to my destination do what I need to do and come back. It was an instant decision. I'd never thought about it before I got in the aircraft.

And that's one of the key findings from the AAIB report, isn't it? They're highlighting the importance of having that go or no go point built into your pre departure briefing. So that leads us into the safety guidance that the AAIB has mentioned, much of it is information that's been published by the CAA. And we're going to look at each of those in turn and get your views on them. But looking at the safety guidance as a whole before we get into those specific publications. Are there any key messages that you want to highlight to pilots?

Yeah, I think the key safety message from especially the report is have a briefing beforehand, even in your head, just go through a pre flight brief we do it generally, when we're flight planning, maybe the day before or the morning before the flight, we would plan okay, this is our route. But actually do we plan? What could go wrong? What threats can we associate with the flight itself. And you are taught to a relatively small degree in your flight training about pre departure briefing, more in the commercial side when you progress if you want to go through to the commercial route. But it's more of a briefing that we get you to discuss are more of okay, this will be a takeoff from this runway, we'll do a right turn, climb out, stay below this altitude. And actually, you can incorporate the other threats of if I'm not running down the centerline, if there's unusual acceleration or I'm not at the speed, I want to be at a certain point. That's a good point to have in your head a predetermined point. And it gives you that structure to understand, okay, it's not a decision I've made really quickly. It's actually something I've though about 10 minutes previous to that flight.

Now the CAA has recently published an article in its Clued Up magazine highlighting takeoff decision making. Please can you take us through the key points that are covered in that article?

The key message really is about the threat and error management and the briefing beforehand which I've mentioned. Threat and error management is not really something that you're taught possibly at PPL levels, it especially wasn't when I got my licence, never heard of it. I think it was maybe called airmanship. But it wasn't something my instructor instilled in me when I was learning to fly. So that's although it's not a new subject it's something that is I think it's being taught more and more in the flying industry now. But it's more about having a predetermined structure to your briefings and actually carry out a briefing, you may think, oh, I don't need a briefing. I've done this hundreds of times, but you've done it hundreds of times. But on the hundred and first time something might go wrong. If your brain hasn't been there five minutes previous, you're going to definitely get that startle effect and that really is what got me I think on that flight was woah, what am I gonna do. Luckily, in my case, I had a longer runway, but in many other cases that I've flown to the runways aren't that long to reject. Yeah, the key is really that good structured takeoff briefing. And just being able to recognize a situation where it's safer to stay on the ground, than actually continue into the air.

Great, thank you. So moving on to the CAA publications and safety information that's mentioned in that AAIB report. One of those is guidance for class, type and instrument rating skills tests and proficiency checks for single pilot airplanes. Specifically, there's a section in there called abnormal and emergency procedures, what do pilots need to be aware of here?

So when you undertake your skills test, both PPL, CPL or LAPL, I think there is a requirement to undertake a rejected takeoff. Those rejected take offs, probably 60% of the time, you know, it's going to happen. So your brain is already ticking over going okay, there's going to be a rejected takeoff soon. So you've already prepped yourself, which is good, in some sense, because we're telling people to be briefed, anyway that you could reject, you're not always going to take the flight into the air. But on these occasions, I think, in my personal experience, and on the documents is therefore really obvious reasons to reject the takeoff. So fire in the aircraft or an animal or a person on the runway. Whereas in GA flying, it's not always that simple. It's not always obvious to reject the takeoff, it could be a slow ASI, something's not quite right with the aircraft, you can't see anything but in your gut, you know, hang on, this isn't quite right. Like in the accident report, the pilot knew something wasn't right, something was unusual, but continued. So it's not always clear cut options to reject. And obviously on skills tests like we spoke about the examiner on the right of the aircraft will say stop. That's a clear indication that you're going to have to stop but you won't have that examiner in the real world situation. It's down to you as the pilot to have that decision making skills and that's really one of the key messages here is that a key briefing beforehand gives you that extra bit of capacity when you're rolling down the runway of what to think about if something goes wrong.

One of the other things mentioned in the AAIB report is the CAA Examiner's form, which includes an assessment of rejected takeoff at a reasonable speed. We've touched on this a little already, in the sense that this will be happening as part of an assessment. So the pilot will know it's coming. But is there anything else that people should know?

Yeah, so it's only a slight little one, I suppose. But the reasonable speed is hard to quantify. Yes, you're going to do it at a reasonable speed, because that's what the test requires to make sure there's a safe outcome. You're not always going to have a reasonable speed, it might be right at the beginning of the roll when you're at a very slow speed. Or it might be the case where you've thought to yourself, okay, I've not got to a certain speed, so I need to stop. So yeah, although it's a good practice in the skills test, it's not always going to be when you expect it at reasonable speeds.

In this particular incident, the aircraft was also a relatively new type for the pilot, is there anything that people should be aware of in that type of situation where they're flying an aircraft, but have maybe gained the bulk of their flying hours on a different type?

Yeah new types, I think, are always difficult to get to grips with as a pilot, even if you're two thousand hours flying in GA, if you've done one thousand nine hundred of your hours in a different type of aircraft, you've gone on to a new aircraft, your brain is not going to be overloaded, but your sensory capacity is going to be slightly different. When you're still getting used to the aircraft, the way it handles something might be different on a different type of aircraft, maybe I don't know the way it handles in a crosswind or the acceleration might be a lot quicker or a lot lower than the previous type. So sometimes your brain can revert to what you're used to. But you just need to remember, I'm in a new type. In this case, I think the pilot undertook quite a few flights with a LAA instructor, which was really good. And because it was a new type, that's what we really encourage is to get somebody with experience on those types to fly with you for a couple, even if it's not mandatory. It shows good airmanship that you're willing to understand. Okay, I haven't got the most experience on this type, someone's in the hangar next door who has flown these before. I wonder if they'll come up with me for a couple. And that's always what we'll encourage, getting your peers to help you in that side.

One of the things that surprised me about this report is that the pilot told the AAIB that he didn't consider rejecting the takeoff. And that seems consistent when we look at a different part of the report where it mentions that every flight instructor that the AAIB interviewed during the investigation indicated that when pilots are preparing for a takeoff, they're usually focused on getting into the air rather than considering a rejected takeoff. As a pilot yourself, Paul, was that a surprise to you as well?

No, it wasn't because I think the only time I'd ever practiced for a rejected take off or even thought about it before I started flying on my own was during skills tests, and maybe the lesson before a skills test where the instructor would go, okay, we're just gonna practice rejected takeoff because maybe you'll do one tomorrow on the skills test. Not throughout that whole flight training did they say okay, we're going to learn about rejected takeoffs. And I think that's maybe a little bit late in the training course to start doing that. It may have just been my personal experience. But it sounds like it's actually quite a common theme, possibly throughout certain flight training industry. But it doesn't surprise me that once outside of the learning environment and you're flying on your own, didn't think about a rejected take off? No that doesn't surprise me because as I said at the beginning, I'd never thought about rejected takeoff in my pre flight briefings. Majority of my briefing before flying was about where am I going to go? What altitudes am I going to fly? What headings am I going to fly? Not about, okay, what could go wrong on the takeoff, what could go wrong on the flight or could go wrong on the landing. That never really occurred to me until probably about a year ago, in GA flying. This is actually really helpful for me, it made me feel a lot more confident, flying GA, knowing that I've really thought about what happens if this happens. And sometimes it's just even just before you line up, or just before you even start the prop, you're sitting in the aircraft, you just doing all your checks. Take five minutes, have a brief okay, we're using this runway today the wind is from the left, the grass is a bit wet. I've not flown from a wet grass for a while, it may be slower to accelerate than normal then in the takeoff, it'd be a right turn if an engine fails. It's what I'm gonna do. It's just going through that in your head. So if it does happen, it reduces that startle factor. So yeah, I'm not surprised that some pilots have not thought about rejected takeoff.

We were talking a little earlier before we started recording about how in commercial aviation, there is a defined structure in place around when to reject a takeoff. Why do you think there is this difference in terms of how it's focused on when it comes to general aviation?

Yeah, I think in the commercial side, it's very structured. There's defined criteria of when to reject a take off and 9 times out of 10 you've got another pilot next to you and in the first part of my commercial career, it was a single pilot. So I was on my own. But in GA, we don't have that set structure, we don't have those defined criteria, we don't have those systems onboard the aircraft that can alert us to something's not right, reject the takeoff, you don't have that in GA. So I think it can be quite difficult to incorporate that into the GA world. Some of the GA aircraft are really well equipped. So yes, they can alert you to this. But it's about really just using your experience and your knowledge. And if something doesn't feel right, something probably isn't right. And even if you reject a take off because it doesn't feel right and nothing was wrong, you've done the right thing because you weren't in the right frame of mind, something to you didn't feel right. So reject it. Go back to the clubhouse sit down five or ten minutes, if you think, okay, nothing was wrong. Work out. Okay. Can I go again? Shall we have another go? Or should we just say no? Okay, that's enough for today. I think I'll come back. We'll try again tomorrow. So yeah, it can be difficult to bring that structure into GA. But again, with the majority of GA aircraft, we don't have anti skids on our brakes. So you slam on those brakes, you probably will have a skid, it's not a bad thing, but these are their pride and joy for a lot of pilots, and they don't want to damage the aircraft. So sometimes they think, okay, it might be safer to take into the air. But in reality, it's probably safer to keep it on the ground, than to try and take a problem into the air where the aircraft might not be stable on the initial climb, and you could be worse off.

Thanks, Paul. So the safety guidance we've discussed so far has been aimed at pilots. But the AAIB has also highlighted some information for flight training professionals. Please, can you talk us through that? Particularly the CAA training comm published in '19, that is mentioned in their report?

Yeah. So I think one of the key points was around the flight with an instructor during your refresher training. And a lot of pilots I think, see it as a oh no I've got to fly with an instructor or that sort of mindset. And to be fair, I originally had that mindset, I was I'm free, I've got my PPL licence, I'm going flying in two years time I've got to go back with an instructor. But actually what that taught me was, I could use that time with the instructor to help me develop on my weaker areas. And I think they try and pick up on that in the safety comm, using that time that you have with an instructor to actually develop those weak areas or those points in your flying that maybe you're not as confident in or maybe you haven't done it for a little while. So do it on the refresher flight. I think in the safety comm, I think the AAIB bring out that it is a valuable opportunity to bring up these weak points that they see possibly from when talking to pilots. It shouldn't be seen as Oh, now I've got to fly with an instructor. It's okay. This is an opportunity for me to develop in an area that maybe I'm not as confident in as maybe I was two years ago.

So we've covered the guidance that is mentioned in the report. Are there any other resources that you'd recommend pilots look at that could be helpful in this area?

There's loads of information out there for pilots to read one of them again, we've probably mentioned it on previous podcasts or other Clued Up articles, is the Skyway code. We don't actually have a section in the Skyway code on rejected takeoffs. But we have a section on decision making in the Skyway code. And that brings in that threat and error management that I spoke about earlier. So it's only I think it's only half a page, but it does link to a bigger document, but that half a page on decision making. Next time before a pilot goes flying, just have a look and go through the points in the decision making. You can say yes, I've covered all those. So that'd be my advice. The last time I flew GA was probably about two months ago. So yeah, I definitely got out the Skyway code and had a look and just to refresh my memory on areas that I wasn't too on top of at the time.

That's great. Paul, thanks very much for talking us through all of this safety information.

Thank you.

You can find links to all of the resources that we've been talking about in the notes for this episode. Thanks again to Emma Truswell at the Air Accident Investigation Branch for speaking to us about their investigation. We've included a link to their report in the episode notes too. So that's it for this episode, but if you have any feedback or suggestions for subjects that you'd like us to cover in future episodes, please contact us at safetyfilespodcast@caa.co.uk. Thanks for listening.

Thanks for listening. This is the CAA Safety Files.