pplmuppet
5th Jun 2006, 18:40
Hi All. It's been a while since i posted in this forum, and thanks to those that provide the service. (i had another username many years ago but have forgotten it), hopefully, i can either provide some insight to others, or others can help us all with a dilemma i recently experienced. I am not essentially looking for the 'was it the right or wrong decision?', type answer or confirmation of my decision, i think it is more of opening up a topic for discussion and maybe a learning process
A brief background. I recently attained my PPL, this year and subsequently moved countries in the process having done my PPL in another JAA state. In the new country i found a flying club with seemingly reasonable machines and reasonable prices. Now here comes the interesting part.
Having low hours, around 60, I decided to get a check flight in one of the club's a/c, as it happens a Robin DR 400 160HP Romeo Kilo. The check ride was interesting to say the least as i hadn't flown this type before (Piper Cadet 161 was my training a/c) and it was little more responsive than the trainer i had used, it was also a stick as opposed to a yoke. But never the less i managed to get 1h:15mins on type with the club instructor. After the flight i wanted to go and take it for a spin at the weekend, so as i had been trained to do i wanted to get the flight manual for the true stall speeds, fuel consumption and more importantly C of G limits (mass/balance calcs). The instructor copied them for me and so i took them away to do my pre flight.
Arrived at the club on a beautiful 320/10kt CAVOK, 23/06 1025 day. I saw the a/c parked and thought i will check the fuel and last minute mass/balance. Fuel was 1/2 full. I noticed that i had reserved another a/c of the same type DR 400 but 140HP Kilo Charlie, Romeo Kilo was not available, the flight manual i had used was for check flight 160HP a/c Romeo Kilo. Stickered on the side was AVGAS 110L capacity. Not the 100 that the mass/balance graph had indicated ie 72kg.
2 problems had transpired. The Kilo Charlie flight man was not available to check the specific weights, even in the A/C the Romeo Kilo Flight man was used! Upon further investigation on the full flight man of the only available manual for type, Romeo Kilo, the text says MAX Fuel 110Litres, of which useable 109Litres. The graph for the mass balance fuel was maxed out at 72kgs, ie 100L. It was impossible to calculate max fuel of 110L ie 79.2. Even after discussion with various members of the club including instructors, who were also perplexed at the discrepancy. I was none of the wiser in coming to a decision about the flight. Should i go or not? The doubt was there, although i 'knew' that there would not be a problem considering the difference of 9.2kgs and the mass moment of the centre tank, practically along the pitch axis of the a/c, and only pilot and 1 light passenger and no bags. Surely the C of G was well within limits? I elected to cancel the flight, although annoyed and frustrated.
I would welcome comments critical or otherwise, or just general advice on this subject. As an additional note, a lot of the club members/instructors seemed a little blasé about the whole affair. Yes the a/c is capable of 4 passengers and full fuel and still remain in limits, and i have very little doubt that there would have been any problem, but there would have always have been that niggling thing whilst flying in the back of my mind about the mass balance calcs. I have read many accounts of accidents involving c of g errors even from professional pilots, and the all too well known case of, flying based on another pilot's view point or advice. ie the mentality of, sure it'll fly with 14 passengers and fuel no problem, i've done it thousands of time, and never had a problem. My luck would most likely dictate the opposite. Comments welcome.
NB after research i discovered that the DR 400 was previously certificated for useable fuel of 100L Max cap of 110L, then it was changed post '92 to 109L useable. Did somebody forget to update the graphs?
A brief background. I recently attained my PPL, this year and subsequently moved countries in the process having done my PPL in another JAA state. In the new country i found a flying club with seemingly reasonable machines and reasonable prices. Now here comes the interesting part.
Having low hours, around 60, I decided to get a check flight in one of the club's a/c, as it happens a Robin DR 400 160HP Romeo Kilo. The check ride was interesting to say the least as i hadn't flown this type before (Piper Cadet 161 was my training a/c) and it was little more responsive than the trainer i had used, it was also a stick as opposed to a yoke. But never the less i managed to get 1h:15mins on type with the club instructor. After the flight i wanted to go and take it for a spin at the weekend, so as i had been trained to do i wanted to get the flight manual for the true stall speeds, fuel consumption and more importantly C of G limits (mass/balance calcs). The instructor copied them for me and so i took them away to do my pre flight.
Arrived at the club on a beautiful 320/10kt CAVOK, 23/06 1025 day. I saw the a/c parked and thought i will check the fuel and last minute mass/balance. Fuel was 1/2 full. I noticed that i had reserved another a/c of the same type DR 400 but 140HP Kilo Charlie, Romeo Kilo was not available, the flight manual i had used was for check flight 160HP a/c Romeo Kilo. Stickered on the side was AVGAS 110L capacity. Not the 100 that the mass/balance graph had indicated ie 72kg.
2 problems had transpired. The Kilo Charlie flight man was not available to check the specific weights, even in the A/C the Romeo Kilo Flight man was used! Upon further investigation on the full flight man of the only available manual for type, Romeo Kilo, the text says MAX Fuel 110Litres, of which useable 109Litres. The graph for the mass balance fuel was maxed out at 72kgs, ie 100L. It was impossible to calculate max fuel of 110L ie 79.2. Even after discussion with various members of the club including instructors, who were also perplexed at the discrepancy. I was none of the wiser in coming to a decision about the flight. Should i go or not? The doubt was there, although i 'knew' that there would not be a problem considering the difference of 9.2kgs and the mass moment of the centre tank, practically along the pitch axis of the a/c, and only pilot and 1 light passenger and no bags. Surely the C of G was well within limits? I elected to cancel the flight, although annoyed and frustrated.
I would welcome comments critical or otherwise, or just general advice on this subject. As an additional note, a lot of the club members/instructors seemed a little blasé about the whole affair. Yes the a/c is capable of 4 passengers and full fuel and still remain in limits, and i have very little doubt that there would have been any problem, but there would have always have been that niggling thing whilst flying in the back of my mind about the mass balance calcs. I have read many accounts of accidents involving c of g errors even from professional pilots, and the all too well known case of, flying based on another pilot's view point or advice. ie the mentality of, sure it'll fly with 14 passengers and fuel no problem, i've done it thousands of time, and never had a problem. My luck would most likely dictate the opposite. Comments welcome.
NB after research i discovered that the DR 400 was previously certificated for useable fuel of 100L Max cap of 110L, then it was changed post '92 to 109L useable. Did somebody forget to update the graphs?