EXERCISE 5: Taxying
In the olden days when everything was black and white, the RAF taught me that a taxying accident is unforgivable. Their exact words.
Now, fast forward to the 1960s and the subject comes up again. I am enjoying a chat with Phil Smullian, the boss of Air Cape’s charter ops and a much decorated WW2 RAF pilot. .
I always enjoyed Phil – he was a rotund, smiling guy with a big walrus moustache and a brilliant sense of humour.
The naughty fuel pump
Suddenly there’s a crash and Ray Grinstead bursts into the office – all arms, legs and excuses. Ray was the sort of guy who was always bursting into rooms – not a quiet and peaceful individual.
His excitement was generated by the fact that he had just taxied the company’s Chieftain into a fuel pump. He was explaining that it was not his fault because the windows had misted up.
Ray was not RAF trained and didn’t have the benefit of their views on taxying accidents.
Phil leaned back in his chair and viewed Ray’s performance patiently with his arms folded comfortably over his ample stomach. A single raised eyebrow made it plain that he doubted Ray’s sanity.
Eventually, when Ray ran out of steam, Phil said softly.
“Ray, it seems we have three protagonists here. An aeroplane, a fuel pump, and yourself. Please go and sit quietly in the crew-room and think about this. Let me know when you have decided which one was at fault.”
Charlie Brown
Here’s another brief story about the longest taxi in the world and this wonderful little Colt of mine: ZS-CBN.
We were on our way back to George from the Margate Air Show. I was flying my magic Grob G109B in loose formation with Charlie Brown when he had a complete and sudden engine failure
The pilot, Wally Nell, landed Charlie neatly in pretty rough terrain in the bush. No damage.
I circled overhead and was much puzzled by this development. Engines don’t suddenly stop with no warning, but Charlie Brown obviously didn’t know this.
I told Wally to try a restart, which he did, and the naughty little bugger ran as smoothly as a sewing machine. I got Wally to take her up to full throttle and hold her there for five minutes – absolutely no problem.
Now what the hell do I do? I can’t trust the little rat after that display, but at the same time I can’t afford to have it put on a truck to the AMO in PE.
I told Wally to knock down the fence and get Charlie Brown to the main road, while I flew the 35 odd nautics to Port Alfred.
Once there I got the cops on my side and they drove me to the Colt and escorted me back while I taxied the 55 road kilometres to Port Alfred.
The Colt took to this like a kid to cookies – no overheating, no scrubbing of tyres, no cooking of brakes. He would have happily taxied to Johannesburg if I had asked him. Yes, ‘he’ and ‘him’ Colts and Tri-Pacers are definitely male, they are tough like tractors.
The engine stoppage was caused by a small rectangle of aluminium plate, actually an airflow straightener just below the mouth of the carb. This broke off and got sucked into the venturi where it blocked the airflow. Of course, when the engine stopped the plate fell to the bottom, and the engine again ran sweetly. Charlie Brown was fixed and flying happily the next day.
Flight test forms
In the days before Pontius was a student pilot, we used massive flight-test forms that required us to allocate numbers between 0 and 9 for each part of each exercise. Thus, the first aspect of a medium turn was ‘safety precautions’. We would give you 0 if you didn’t look out for other traffic. Or 9 if your lookout was so exaggerated as to be comical.
The number we allocated would be multiplied by a loading factor and the total would then indicate how much pleasure or pain your performance had caused us.
So, if your lookout was a bit half-hearted and only warranted a 4, this would be multiplied by the loading factor of say 5, to reward you with a total of 20 points for lookout prior to medium turns.
As each exercise consisted of perhaps half a dozen aspects, with each aspect having its own mark and its own loading, there were eventually a vast quantity of numbers scattered over the form. Afterwards we would go into a quiet corner with a pencil and rubber – we didn’t have calculators in those days – and total all these numbers to find whether you had passed or failed.
You were eligible for a couple of thousand points if you did everything properly.
The interesting part is that we would take huge pride in writing a secret number on the back of the form, before takeoff. This number, based entirely on your start-up and taxying, would be our guess of your final score.
Amazingly it was invariably correct within a couple of percent.
I’m saying the way you handle an aircraft on the ground is a faithful reflection of the way you fly it.
When you are being tested the DE will look for the following. It’s all covered in the flight-test (sorry skills-test) form under : Section 2: Pre-flight Operations
You get a 1 to 4 evaluation now. 1 means dreadful, but officially called ‘not yet competent’. I hate this PC-ness. We aren’t allowed to say ‘fail’ because it might offend the guy who has been trying to kill you. 2 means sub-standard. 3 means you meet the standard. While 4 indicates that you are something of a golden boy, or girl.
So, using these performance classifications, here’s what you will be trained and tested on, before takeoff.
| Aspects | ||||
| Pre-flight inspection, cockpit preparation, passenger briefing, etc. | 1 | 2 | 3 | 4 |
| Engine start and after-start procedures | 1 | 2 | 3 | 4 |
| Taxying and aerodrome procedures | 1 | 2 | 3 | 4 |
| Pre takeoff checks and crew briefing | 1 | 2 | 3 | 4 |
Let’s look at each aspect in turn:
Pre-flight inspection, cockpit preparation, passenger briefing, etc.
We discussed this before, but basically the preflight must be unhurried, and by the book. It must also cover a methodical, round-the-cockpit inspection of everything inside the cabin. Including such things as the floor being free from oil cans that may roll under the rudder pedals.
I actually tested a guy who could see nothing wrong with having a Coke bottle rolling around the floor in a tatty 172 with a dirty windscreen. I don’t think we were in the air more than ten minutes before he did something so heinous that I called off the test and never saw him again.
Do you remember the Ravin that scraped its tummy along the runway on takeoff at Wonderboom. It seems the pilot didn’t notice that the undercarriage selector was somehow in the UP position. All was fine until he rotated for takeoff. The squat switch on the nosewheel sent a message to all stations saying, “Up with the gear, guys”. Sad, but it tells me the pilot twice failed to check the gear selector. He should have done it during his pre-start round-the-cockpit checks, and then again during his post start round-the-cockpit checks.
Now let’s look at passenger briefing. The extent of this depends on who your passenger is. If this is their first flight, you will have to be particular about what they may and may not touch. How to work the intercom. Where the fire-extinguisher is stowed. How to work the door and the emergency exits. And how to adjust their seat and so forth.
I once had serious conflict with a charter pax who grabbed the stick of a Cessna 182, soon after takeoff from George. He put his great hairy mitt on it and yanked – with alarming results. I whacked his arm and spoke harsh words. He thought the wheel was a convenient handle to heave himself forward while adjusting his seat.
Unbelievable. But it was my fault – poor briefing.
Then there was the old, experienced Dak pilot who was known as Father Christmas because of his massive white beard. He was being tested for an IF renewal in Cape Town by a notoriously unpopular DCA inspector, whom I will call Goosy.
As Father Christmas released the brakes to taxi, Goosy said, “Haven’t you forgotten my briefing?”
Father Christmas brought the aircraft to a halt and turned to face Goosey, “Indeed I have. Thank you for reminding me.” He paused. “Here’s your briefing. In this cockpit, you are to keep your hands and feet off everything.”
“What happens in the event of an emergency?” bleated the offended Goosey.
Father Christmas looked him in the eye. “Particularly if there’s an emergency – do… NOT… touch… anything.”
This briefing is particularly important if there are two licenced pilots in the front, or two crew members. Their duties and responsibilities must be clearly defined. Who is navigating? Who is doing the radio work? Who is working the levers and pedals? And who is going to be doing what in an emergency.
Engine start and after-start procedures
Start-up is very easy. Confirm you will be able to taxi forward from where you are. Make sure the brakes are on, and that you are not going to blow dust at anyone. Switch on the beacon to warn bystanders. Now do exactly what the POH says.
Remember to clear the prop – you need to take this seriously and get your pax or instructor to check on their side. Imagine mangling a toddler or a dog.
If you set the throttle too high and the revs scream before you throttle back, expect an old-fashioned look and a low mark. That is about the worst thing you can do to a cold engine – letting it rev before the oil circulates.
I say again – good engine handling is the hallmark of a good pilot.
As soon as it’s running, stick your finger on the oil pressure gauge. And while you are waiting, glance at the ammeter – it should show a high charge for a short while, to replace the power used by the starter.
Settle at the POH idling revs.
Now do another complete round-the-cockpit check, switching on the things you will need – radios and so on – setting frequencies, checking the ATIS, and switching off the things you don’t need, like the electric fuel pump.
Taxying and aerodrome procedures
First you must know where you are going to taxi to. The windsock should have given you an idea, and the ATIS should have made it clear. If it is a complicated airfield you may need a map to find your way.
Let’s assume you know where you are going, have obtained clearance, made sure it is clear in front, and have anticipated what the wind and gradient are going to do to you. I will come back to wind and gradient in a moment.
How do you start taxying? Most pilots have a two point system – 1) release the brake, 2) use enough power to get moving. Sound about right? If you were doing a SAAF flight test, your instructor would tell you to shut down the engine and come back when you had learned to taxi.
Here’s how an Air Force pilot starts taxying, and I can see no reason for civvies to do it any other way:
- Throttle fully back. This confirms that the carb’s slow idle is set correctly and she doesn’t die through carb icing, which is common on a damp morning, and difficult to detect. Also you don’t want the aircraft leaping forward like a racehorse out of the box.
- Release the park brake.
- Take enough power to get moving.
- Throttle fully back again.
- Brake to a full stop with the toe brakes.
- Use enough power to overcome inertia.
- Throttle back and use power to adjust your speed.
So now you have started taxying and you are going at a walking pace until you are away from other aircraft and people. Keep the nosewheel on the white line.
Taxying in the wind
If your aircraft is light enough to be affected by the wind, then be sensible about which way you hold the control column – particularly if you are in a taildragger.
The rule is: climb into wind, and dive out of wind.
This means that if the wind is from the front, keep the stick back (climb) and the ailerons into wind. And if you are going downwind (dive) keep the stick forward and the ailerons the wrong way. So the wind is coming from say your 4 o’clock position, you should hold the stick forward and to the left.
The exception: if you think your slipstream over the elevator is outdoing the tailwind, then the stick will be back, but the ailerons will still be the ‘wrong way’.
Watch those brakes
One of the most common taxying sins is to ride the brakes. You wouldn’t do it in a car, so why do it with an aircraft?
Perhaps the worst taxying accident of all time was on 27 May 1982. A 24 Squadron SAAF Buccaneer landed safely at Pietersburg after a hydraulic problem. The pilot then decided to taxi – despite the QRH (Quick Reference Handbook) saying “NO TAXYING” after hydraulic problems.
All went well until the hydraulic pressure expired just as the taxiway sloped down to where four Impalas were parked. On impact, the Bucc and one Impala caught fire and the rest were either written off or seriously damaged.
That was a case of post event euphoria. They were so elated to have landed safely they stopped thinking.
Earnest Gann did a similar thing after doing a hectic spiral through the clouds in a four-engine passenger aircraft that had a fire in the hold. He got safely on the ground and then taxied the burning aircraft to park at the fuel bowser.
Situational awareness is critical. Not only do you have to concentrate on the job in hand, you must also be aware of other aircraft, vehicles and people on the ground, as well as circuit traffic, the wind, the surface, the gradient, your inertia, engine temperatures, brake temperatures, carb-icing and right of way. The position of the sun can be critical for visibility and can even cause an epileptic fit when flickering through the prop.
And when you get to the threshold or holding point, this is where your airmanship really shows. How do you decide where to stop, and which way to face? And are you going to pick up stones in the prop, and will you blow crap at another aircraft? There is a whole bunch of stuff to think about:
Okay, the Gleitch says I must wrap it up now – he only gives me 2,500 words a month and I have to arrange them in such a way that you are either informed or entertained. I’ll try harder next month.