Vtoss or V2 is typically 10-15% above Vmca (regulatory minimum 1.1x Vmca). Most twins would struggle to meet ASDR with 600 m available (am thinking PA34 or C340), and if ASDR charts are published in the POH they are a limitation. Not sure what a lightly loaded C90 might need, but even going into full reverse (not great technique due to noise and propeller care) 600 m looks tight, even before public transport safety factors.
This comprehensive Australian accident report on a charter C90 EFATO states 1,300 m as the ASDR for the incident.
I have to apologise the runway at Sarlat LFDS is 747ft long. The guy who bought the C90 was based there. He owned a ULM agency, I think.
gallois wrote:
I have to apologise the runway at Sarlat LFDS is 747ft long.
did you kmean meters?
Oops I did🤪
Airborne_Again wrote:
Could you rotate after Vmca if taking off from such a short runway?
Quite a few twins have rotation speeds below Vmca on short field ops and take this into account. EFATO below Vmca would mean immediate reduction of power on BOTH engines and land straight ahead like with a single.
The time between rotation and Vmca is usually quite small, particularly if you lower the nose after unstick and get the speed first. It is a calculated risk.
I recall the King Air from my then FI in 1983 and it looked huge to this C150 pilot then. Yet, when I had the chance to fly it once, I was very surprised how pleasant it was to fly and comparatively easy too.
(Had a chance to try a Twin Bonanza too during that time. It later got sold for a song… I’d have picked it up if I had known. lovely airplane but also huge and tall. But very nice to fly and impressive performance. )
What I have heard quite good things about is the Cheyenne I when it comes to short field and even grass ops.
I have a few hours Baron 55 time and even less BE95 Travel Air. I liked both. They are great airplanes. The Baron is handicapped with +2T MTOW but the Travel Air is not. I suppose that is why the Senecas (1999 with STC) became the standard trainer for most schools.
Quite a few twins
I can only think of gravel ops in the Twin Otter, all twins can take off below Vmca but Vtoss is at least 1.1x Vmca
The early twin jets didn’t have Vtoss as Vmca was many seconds after lift off, hence the Meteor known as the Meat Box!
RobertL18C wrote:
all twins can take off below Vmca but Vtoss is at least 1.1x Vmca
If I remember correctly the short field take off ops with both the Seneca and Twin Com has Vr and lift off below Vmca.
What is Vtoss? I thought this speed applies to helicopters?
Take off safety speed – speed at which the aircraft will climb with one engine inoperative – should be the initial acceleration target; but of course operationally you always want Vyse
Most advice in a light twin is not to rotate before Vmca. Sometimes with a light load this can be difficult as you need to hold the aircraft on the ground without allowing it to wheelbarrow.
Mooney_Driver wrote:
If I remember correctly the short field take off ops with both the Seneca and Twin Com has Vr and lift off below Vmca.
Close, but actually the Seneca V has a Vmca of 66 KIAS and the short field technique has a Vr (technically a lift off speed for a puddle jumper) of 73 KIAS, so meeting the 1.1x requirement. Flapless the Vr is 81 KIAS, and the difference in Vr is due to the Vs is lower by 6 knots with flaps 25 (67 vs 61KIAS). My PA-30 POH is at home so will compare notes on that. Helpfully the PA-30 POH is paranoid about asymmetric operations (the revised PA-30 POH introduced the FAA concept of Vsse), with full page warnings on there be dragons there, etc
It is OK to allow lift off before Vmca and avoid ramping/wheelbarrowing, but you are expected to maintain level until achieving Vtoss.
