Life as Ground Crew: Fuel Inspections & Contaminations.
I currently working at an airfield alongside my weekday and weekend job. I joined the airfield on a voluntary basis as I was super passionate to get involved in aviation any way I could before starting training. I’d definitely recommend anyone passionate as I am to get stuck in and get to work with their local airfield or aero club. Although fuel checks means early mornings (7.30 am) and long days the enjoyment and fulfilment outweighs the hard graft!
A typical day at the airfield starts with runway checks (which we have covered already) followed by fuel checks. There are two types of fuel at the airfield: AvGas and JetFuel.
~ INTRODUCTION TO FUEL ~
AVGAS
Avgas – also known as aviation gasoline is used by spark ignition piston-engine aircrafts. This is predominantly for planes with propellers, such as the Cessnas and Piper Clubs. Now there are two types of Avgas: Avgas 100 and Avgas 100LL. Both types differ based on the lead content, for example AvGas 100 has a high lead content vs AvGas 100LL which contains low lead (LL). The ‘100’ written aside Avgas refers to the Octane rating – this is a measure of the resistance to detonation. A high resistance means more fuel to air mixture can be compressed without ignition occurring. This is great because for a given fuel burn – there is more output and thus better engine efficiency per compression/ignition cycle.
Avgas 100LL is the version used at the airfield I work at. If you’re confused whether you’re using Avgas 100 or Avgas 100LL (in the case you SOMEHOW miss the labels at the fuel pumps and on the aircraft fuel caps) you can distinguish both by their distinct colours. Avgas 100 has a green colour whereas Avgas 100LL has a sky blue colour.
JET
To make things more confusing there are also two types of Jet fuels – Jet A and JetA1. There are some differences in specifications, such as different freezing points (Jet A: -40C; Jet A1: -47C) but both can be used interchangeably. Jet A is mainly used in America whereas Jet A1 is used all over the world. The colour of Jet A1 is almost transparent with a faint of tint.
Jet A1 is the version used at the airfield I work at. This is available for helicopters at the airfield (whilst some helicopters can use both Avgas 100LL and Jet A1). There has been instances where student pilots have fuelled up piston engine aircrafts with Jet A1 by mistake! Hence now it is procedure at the airfield to switch off Jet A1 once fuel checks are completed.
~ FUEL CHECKS ~
Full audit trail + Fire Extinguishers
One of the most important aspects is to complete an audit trail of the fuel checks when done every time. Like many airfields there will be a pre-filled fuel check sheet that requires your name, tank readings, dips readings and any observations or cause for concern. The second most important thing to do is ensure every morning fire extinguishers are made available and within reach vicinity when carrying out checks.
Tank readings
At my airfield there are 2 AvGas pumps and 1 JetFuel pump – Tank A, B and C. First, tank readings are taken – these are done to identify which tank is low on fuel and needs a re-fill. If a tank is low on fuel – the ground crew manager is informed and the tank-pump in question is turned off until re-filled (which is usually a day).
Meter readings: Fuel pumps + Bowsers
A meter reading is taken of the 3 pumps – just like your gas meters at home there is a screen that has the meter digits written. Since there is two AvGas meters to record the meter reading is taken from the first pump and is then reset for the second pump. So far it isn’t too difficult except for certain codes to remember – this will vary from airfield to airfield. If there are any bowsers at the airfield – readings from them are also taken.
Contamination checks: Pumps + Bowsers
During fuel contamination checks we are first looking for contaminants, such as water. If the fuel pump is contaminated with water this risks the formation of ice crystals in the aircraft fuel tanks and/or fuel lines at high altitudes. Water is a common contaminant particularly where fuel has been stored in tanks and overtime moisture build up. This may occur if fuel in underground tanks has been extracted and placed into fuel bowsers.
We’re also looking for particulates, such as airborne solids (dust and pollen) that enters the bowsers through opening/closing bowsers or entering through damaged hoses when refilling. The presence of even small amounts of water can introduce rust overtime which may build up and eventually find its way into an aircraft fuel tank. Microbial growth is another form of contaminant that is often associated with fuel tanks. Micro-organisms like fungi and bacteria are present virtually everywhere. Certain microbes accelerate erosion and rust formation through byproducts formed. Therefore it is important regular, thorough fuel checks are completed to ensure the fuel is safe to use by pilots who will be flying short and long distances – sometimes cross country or over the channel.
- Empty previous fuel samples
Fuel samples taken previously are normally stored away in a fuel cupboard. These are first emptied into interim fuel tanks (later all the fuel within the tank is tested and transferred back into the main tank). Next, the fuel containers are filled up with Avgas and Jet fuel for contaminant testing – the Jet Fuel switch is normally switched off to avoid student pilots mistakenly filling up piston engines with Jet Fuel (instead of Avgas) – so this is switched off straight away after the samples are filled up.
- Testing for contaminants
A dipstick is placed inside the fuel sample chambers and tested for contamination. A dye is placed on the rod and this will turn red if the fuel is contaminated. In such case this will need to be reported and a full tank testing will be required. Fuel bowsers are mobile fuel trailers situated at either end of the airfield or near hangers – these are also checked to identify if there is any contamination of fuel. All containers from pumps and bowsers are then stored in the cupboard.
It is important when you are filling the testing containers to check for contamination – safety gloves are worn and it is done away from you. In addition to this fuel should fill the containers slowly in order to prevent the fuel spilling over. Once the fuel pumps and bowsers are checked and are safe to use – the audit form is completed and stored safely. If there is any cause of concern – even if it is minor this is always reported back to the ground crew manager and ground crew team.
Summary
The procedure to fill and test for contamination will vary with each airfield depending on whether you have individual logins, fuel cards or devices in order to do this. But the objective and the outcome is the same – all airfields and ground crew teams aim to provide a safe working aerodrome where instructors, student pilots and recreational flyers can safely fuel knowing thorough, consistent and regular checks are completed to the best standard of safety. Whilst my team and I normally do these checks super early (7.30am) it is for sure a great way to start a good day. Shortly after, I watch from the window sipping on hot tea as planes arrive to fuel and taxi for takeoff!